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Tackling Obesity: Its Causes, the Plight and Preventive Actions
Tackling Obesity:
Its Causes, the Plight and Preventive Actions
Central Health Education Unit
Centre for Health Protection
Department of Health
2005
Tackling Obesity: Its Causes, the Plight and Preventive Actions
©
Department of Health
Copyright 2005
Produced and published by
Central Health Education Unit, Centre for Health Protection, Department of Health, Government of Hong Kong Special
Administrative Region, 7/F, Southorn Centre, 130 Hennessy Road, Wan Chai, Hong Kong.
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Tackling Obesity: Its Causes, the Plight and Preventive Actions
Foreword
Obesity is a major public health problem worldwide.
2.
encourage health promoters to adopt evidence-
Its rising trend is evident in both developed and
based initiatives in the management of obesity/
developing countries. There is also a significant
overweight in the population; and
increasing trend among the younger age groups to
3.
become obese.
facilitate planning and development of strategies
for managing obesity/overweight in the
population.
Hong Kong is also affected by the global epidemic
of obesity. Local data suggest that 20.1% of men
The contents of this document include:
and 15.9% of women are overweight, and 22.3% of
1.
men and 20.0% of women are obese.i
an overview of the problem of obesity and
overweight, and their consequences both locally
and globally;
Obesity threatens our health and creates an
2.
enormous burden to our society. It results in ill
health, reduced quality of life, premature deaths,
increased health care costs and reduced productivity.
a brief introduction of the different initiatives
conducted locally and overseas; and
3.
a summary of the effectiveness of various antiobesity initiatives.
Urgent actions are required to address the obesity
epidemic.
There are a number of ways to manage obesity. They
range from preventive measures that maintain healthy
The Department of Health of the HKSAR
weight and prevent weight gain to treatment options
Gover nment is committed to reducing the
such as dietary modification, physical activity,
prevalence of obesity in Hong Kong. However, to
behavioural therapy, drug therapy, combined
effectively manage the obesity epidemic, everyone
therapy and surgery. The discussion in this
in the community must take responsibility and
document, however, is confined to initiatives that
action. The synergy generated from our
prevent obesity/overweight. Treatment of obesity/
collaborative efforts will enable us to tackle the whole
overweight using medications and different therapies
range of factors that contribute to the obesity
is beyond the scope of this document. Furthermore,
epidemic.
this document mainly makes reference to initiatives
known to the Department of Health.
This document serves as the first step in our
campaign against obesity. It aims to:
1.
increase awareness of the problem of obesity/
Dr Ray Y L CHOY
overweight among health promoters and
Head, Central Health Education Unit,
relevant stakeholders;
i
Department of Health
Department of Health. Population Health Survey 2003/2004 (provisional data). Hong Kong: Department of Health.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
i
Tackling Obesity: Its Causes, the Plight and Preventive Actions
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Tackling Obesity: Its Causes, the Plight and Preventive Actions
Contents
i
iv
iv
v
v
Foreword
List of Tables
List of Charts
List of Diagrams
Abbreviations
CHAPTER 1
HOW DO WE MEASURE OBESITY?
Adulthood Obesity
Childhood Obesity
CHAPTER 2
WHY SHOULD WE BE CONCERNED ABOUT OBESITY?
Physical Problems
Psychosocial Problems
Deaths
Childhood and Adolescence Obesity
Economic Costs
7
8
9
9
9
10
CHAPTER 3
HOW COMMON IS OBESITY?
Global Situation
Obesity in Hong Kong
Obesity Related Diseases in Hong Kong
Dietary Habits and Physical Activity of Hong Kong People
11
12
12
15
15
CHAPTER 4
WHO ARE AT RISK?
Biological Factors
Nutrition
Physical Activity
Environmental Factors
Micro-environments
Macro-environments
17
18
18
19
20
20
21
CHAPTER 5
INITIATIVES TO PREVENT OVERWEIGHT AND OBESITY
Infancy
Childhood and Adolescence
Adulthood
Old Age
General (all age)
Environment and Policy
23
24
27
31
33
35
36
CHAPTER 6
RECOMMENDATIONS
41
References
Appendices
Resources Link
Glossary
1
2
5
46
60
65
66
Tackling Obesity: Its Causes, the Plight and Preventive Actions
iii
List of Tables
List of Charts
List of Tables
1.1 Classification of BMI and risk of co-morbidities
3
1.2 Co-morbidities risk associated with different levels of BMI and ranges of waist circumference
in adult Asians in 2000
3
1.3 Recommended sex-specific cut-off points of waist circumference by WHO and WHO WPRO
5
2.1 Relative risk of health problems associated with obesity
9
3.1 Prevalence of obesity by gender in Hong Kong, 1995-1996
12
3.2 Prevalence of obesity by gender in Hong Kong, 2003 (self-reported data)
13
3.3 Prevalence of obesity by gender in Hong Kong, 2003/2004 (provisional data)
13
5.1 Ten steps to successful breastfeeding
25
5.2 Summary of the International Code of Marketing of Breastmilk Substitutes
26
5.3 Definition of one serving size of fruit and vegetable
29
5.4 Items for sale at tuckshops (extract of guidelines on meal arrangements in schools)
38
5.5 Lunch box ingredients (extract of guidelines on meal arrangements in schools)
40
List of Charts
1.1 Median BMI by age and gender in six nationally representative datasets
2.1 Relationship between BMI and relative risk of mortality
6
10
3.1 Prevalence of overweight and obesity (BMI ≥ 23) by age group and sex in Hong Kong, 2003/2004 14
iv
3.2 Prevalence of childhood obesity in primary schools by gender and school year in
Hong Kong, 1997-2002
14
3.3 Prevalence of childhood obesity in secondary schools by gender and school year in
Hong Kong, 1997-2002
14
Tackling Obesity: Its Causes, the Plight and Preventive Actions
List of Diagrams
Abbreviations
List of Diagrams
1.1 Measuring tape position for waist circumference in adults
4
5.1 An advertisement of promoting breastfeeding in MTR station in 2003
26
5.2 Promoting breastfeeding - Baby Expo 2003
27
5.3 “Healthy Eating Movement” for kindergartens and nurseries in 1999
30
5.4 An example of exercise prescription prescribed by doctors
31
5.5 Posters and stickers of point-of-decision prompts in public housing estates
35
5.6 Consultation paper on labelling scheme on nutrition information, issued by Health,
Welfare and Food Bureau in November 2003
39
Abbreviations
The following abbreviations are used in this report:
AIDS
Acquired Immune Deficiency Syndrome
BFHI
Baby-friendly Hospital Initiative
BMI
Body Mass Index
DH
Department of Health
EMB
Education and Manpower Bureau
IASO
International Association for the Study of Obesity
IOTF
International Obesity Task Force
NCD
Non-Communicable Disease
NGO
Non-Governmental Organisation
PE
Physical Education
SES
Socio Economic Status
UNICEF
United Nations Children’s Fund
WHO
World Health Organization
WPRO
Western Pacific Regional Office
Tackling Obesity: Its Causes, the Plight and Preventive Actions
v
Chapter 1
How do we measure obesity?
1.1 Overweight refers to an abnormally high body
simple and inexpensive tools for obesity
weight which may come from bone, lean
assessment. Reference criteria have been set
muscle, fat tissue and water. Obesity is a
up for the purposes of defining obesity and
condition in which the body stores an excessive
identifying associated health risks. It should,
amount of fat to such an extent that health may
however, be noted that they are only guidelines
be adversely affected.1-3
and should not be the sole cr iter ion to
determine whether an individual is overweight
1.2 A certain amount of fat is necessary for normal
or obese.
body functions such as energy storage, heat
insulation, protection of vital organs and carrier
Adulthood Obesity
for fat-soluble vitamins, etc.
Body mass index
1.6 Body mass index (BMI) is an internationally
1.3 Our body can normally regulate overall energy
recognised measurement of obesity for adults
intake with overall energy expenditure without
based on weight and height. It is calculated by
a persistent change in body weight. It is only
dividing a person’s weight in kilograms by the
when energy intake exceeds energy used for a
square of his/her height in metres (BMI=
considerable period of time that obesity is likely
weight in kg/ (height in m)2).
to develop.
1.7 BMI is the most commonly used method of
1.4 Overweight and obesity can be measured by
obesity classification among scientific
assessing weight and height as well as the
researchers and health institutes of different
amount and distr ibution of body f at.
countries. It is economical and highly practical
Computerised tomography (CT), dual-energy
because height and weight can be easily
X-ray absorptiometry (DEXA) and magnetic
obtained without demanding sophisticated skills
resonance imaging (MRI) are examples of body
and equipment. Moreover, BMI is strongly
fat measurement but they are usually not the
correlated with the degree of fatness and
preferred methods by health professionals
obesity-related health risks (co-morbidities).
because of high cost and sophisticated
Therefore, it is used by the World Health
equipment required.
Organization (WHO) as the international
s t a n d a rd o f o b e s i t y d e f i n i t i o n . T h e
1.5 Instead of direct measurement of body fat,
recommended BMI classifications and
body mass index (BMI), waist circumference,
associated risk of co-morbidities are shown in
waist-to-hip ratio and growth charts serve as
table 1.1.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
2
How do we measure obesity?
Table 1.1
Classification of BMI and risk of co-morbidities2
Classification
BMI (kg/m2)
Risk of co-morbidities
Underweight
< 18.50
Low (with increased risk of clinical problems
related to underweight)
Normal range
18.50-24.99
Average
Overweight
Pre-obese
Obese class I
Obese class II
Obese class III
≥ 25.00
25.00-29.99
30.00-34.99
35.00-39.99
≥ 40.00
Increased
Moderate
Severe
Very severe
1.8 As the risk of co-morbidities in relation to
cut-off point for the Asian populations. These
BMI differs among different ethnic groups,
recommendations were based on studies
different cut-off values have been proposed to
suggesting that obesity-related health risks
classify overweight and obesity for different
occur red at lower BMI in certain Asian
populations. In 2000, a joint expert panel of
populations (including Hong Kong Chinese)
the Regional Office for the Western Pacific
which were prone to general and central
(WPRO) of the WHO, the International
obesity. 4 Table 1.2 shows the proposed
O b e s i t y Ta s k Fo rc e ( I OT F ) a n d t h e
re f e re n c e r a n g e s f o r B M I a n d wa i s t
International Association for the Study of
circumferences and their related co-
Obesity (IASO) recommended a lower BMI
morbidities risk in adult Asians.
Table 1.2
Co-morbidities risk associated with different levels of BMI and ranges of waist circumference in
adult Asians in 2000 4
Classification
3
Risk of co-morbidities
Waist circumference
2
BMI (kg/m )
< 90 cm (men)
< 80 cm (women)
≥ 90 cm (men)
≥ 80 cm (women)
Underweight
< 18.5
Low (with increased risk
of clinical problems
related to underweight)
Average
Normal range
18.5 - 22.9
Average
Increased
Overweight
At risk
Obese I
Obese II
≥ 23
23 - 24.9
25 - 29.9
≥ 30
Increased
Moderate
Severe
Moderate
Severe
Very severe
Tackling Obesity: Its Causes, the Plight and Preventive Actions
How do we measure obesity?
1.9
Although the WHO experts did not
the elderly) may be classified as normal even
recommend re-defining BMI cut-off points for
when they are overweight.
different populations after reviewing the
proposal, they suggested Asian countries define
Waist circumference and waist-to-hip ratio
obesity-related health risks for their populations
1.11 The health risk associated with obesity is
based on national data and considerations. A
determined not only by the amount of
few Asian countries such as mainland China
excessive fat being stored in the body but also
and Japan have developed their own BMI cut-
where it is stored.2;5 Excess abdominal fat
off points for obesity classifications.
(central obesity) is as great a risk factor for
developing diseases as excess body fat itself. It
1.10 Despite its wide acceptance, BMI has its
can be identified by measur ing waist
limitations. BMI is neither age-nor sex-
circumference or calculating waist-to-hip ratio.
specific. It does not provide a direct
estimation of body fat accumulation. Thus it
1.12 Waist circumference correlates closely with
may not be suitable for certain population
BMI6 and is a rough estimation of the amount
groups. For example, athletes and individuals
of abdominal fat7-8 and total body fat9 that a
with large body frame and muscle bulk may
body holds. It is measured at the midpoint
wrongly fall into the obese group, while those
between the lower border of the rib cage and
who have reduced lean muscle mass (such as
the iliac crest (Diagram 1.1).
Diagram 1.1 Measuring tape position for waist circumference in adults
Tackling Obesity: Its Causes, the Plight and Preventive Actions
4
How do we measure obesity?
1.13 People of different sexes and ethnic origins
differ in the level of risk associated with a
particular waist circumference. Table 1.3
shows the international recommendations
made by WHO and the recommendations for
adult Asians by WHO WPRO.
Table 1.3
Gender
Recommended sex-specific cut-off points of waist circumference by WHO and WHO WPRO 2;4
WHO recommendations
WHO Western Pacific Region Office
(1998)
recommendations for adult Asians (2000)
Men
< 94 cm
< 90 cm
Women
< 80 cm
< 80 cm
1.14 The waist-hip ratio (WHR) is another
measure of abdominal obesity. It correlates
9
Growth charts
1.16 Reference charts for growth based on weight-
closely with waist circumference. WHR is
for-age and height-for-age have been
calculated by dividing the waist measurement
produced in different countries. However,
(taken at its narrowest point) by the hip
the charts only compare the size of a child
measurement (taken at its widest point). For
with that of other children of the same age.
example, a woman with a 76 cm waist and
They do not take into account the variation
94 cm hip would have a WHR of 0.81 (76
in growth among these children. Therefore,
divided by 94 = 0.81). A WHR value greater
an index of weight adjusted for height can
than 1.0 in men or 0.85 in women indicates
provide a better measure of fatness.
an excess in abdominal fat accumulation and
an increased health risk.10
1.17 In the Hong Kong Growth Survey 1993, sexspecific reference charts of weight-for-height
Childhood Obesity
1.15 Measuring overweight and obesity in children
5
(Appendix 1) along with a series of growth
charts were developed for local references. 11-
and adolescents is difficult because their rates
12
in gaining weight and height vary during
sectional growth survey which covered
developmental stages. At present, there is no
around 25,000 Hong Kong Chinese children
universally accepted method to measure
from birth to 18 years of age. Childhood
childhood obesity.
obesity in this survey was defined as weight
Tackling Obesity: Its Causes, the Plight and Preventive Actions
The survey was a territory-wide cross-
How do we measure obesity?
> median weight for height x 120%. For
1.19 An international BMI-for-age reference curve
example, if the height of a child is 140 cm,
for defining overweight and obesity in
the corresponding median weight-for-height
children 2 to 18 years of age has been
is 35kg. If his/her weight is greater than 42kg
developed jointly by the US National Center
(35kg x 120%), then he/she is defined as
for Health Statistics, Centers for Disease
obese.
Control and Prevention and the IOTF in
2000 (see Appendix 2). The reference
BMI-for-age reference curves
population was obtained from six large
1.18 As for adults, BMI provides a useful measure
nationally representative cross-sectional
of fatness in children. However, BMI in
growth surveys in the US, the UK, the
children varies substantially with age. It rises
Netherlands, Brazil, Hong Kong and
steeply in infancy, falls during the pre-
Singapore. These surveys had over 10,000
school year s and r ises again dur ing
subjects each and together covered 97,876
adolescence. Therefore, BMI in children
males and 94,851 females from birth to 25
needs to be assessed using age-related
years of age (Chart 1.1).13 This may help
reference curves.2
provide internationally comparable prevalence
rates of overweight and obesity in children.
Chart 1.1
Median BMI by age and gender in six nationally representative datasets (from Brazil, Hong Kong,
Netherlands, Singapore, the UK and the US) from an international growth survey in 200013
Body mass index (kg/m2)
Brazil
Great Britain
Hong Kong
Netherlands
23
Singpore
United States
23
Males
Females
22
22
21
21
20
20
19
19
18
18
17
17
16
16
15
15
14
14
0
2
4
6
8
10
12
Age (years)
14
16
18
20
0
2
4
6
8
10
12
Age (years)
14
16
18
20
For adults, the most widely accepted criteria for obesity are based on BMI.
For children, there is no universally agreed method to measure obesity.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
6
Chapter 2
Why should we be concerned
about obesity?
2.1 Obesity poses a growing threat to public health
2.5 Obesity is associated with the development of
all over the world. It is prevalent in both
musculoskeletal problems, e.g. osteoarthritis at
developed and developing countries, and
major weight-bearing joints in the knees, hips and
affects men as well as women, children as well
lower back may be caused by extra weight. Gout
as adults. Gradually replacing the more
is also more common among overweight people.
traditional public health concerns such as
under-nutrition and infectious diseases, obesity
2.6 In women, obesity is related to several
has become one of the most significant
reproductive disorders including infertility,
contributors to ill health.
general menstrual disorders and poor pregnancy
outcome.
Obesity brings about health consequences that
range from physical to psychosocial problems
2.7 Sleep apnoea is a sleeping disorder suffered by
and results in conditions that vary from non-
many obese people. The airway at the back of
fatal conditions affecting the quality of life to
the throat collapses as an individual breathes in
premature death.
during his/her sleep. It can cause daytime
sleepiness, pulmonary hypertension, heart
failure and even sudden death.
Physical Problems
2.2 Health problems associated with obesity have
been studied in various industrialised countries.
There is strong and consistent evidence on the
relationship between obesity and risk of ill
health. Alarmingly, the association begins at a
not very high level of BMI.2
2.3 Obesity is associated with lipid disorders termed
dyslipidaemia and through which, it makes an
individual more vulnerable to a number of
cardiovascular and cerebrovascular diseases
including coronary heart disease, hypertension
and stroke.
2.4 Overweight and obese people are more likely
to develop type II diabetes mellitus which is a
major cause of early death, heart diseases, kidney
diseases, stroke and blindness.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
8
Why should we be concerned about obesity?
Table 2.1
Relative risk of health problems associated with obesity2
Greatly increased by
more than three-fold
Moderately increased by
two- to three-fold
Slightly increased by
one- to two-fold
• Diabetes mellitus
• Gall bladder diseases
• Abnormal lipid or
cholesterol levels
• Sleep apnoea
• Coronary heart diseases
• Hypertension
• Osteoarthritis
• Gout
• Certain forms of cancers (breast
cancer in postmenopausal
women and colon cancer)
• Reproductive hormonal
abnormalities
• Low back pain
• Impaired fertility
2.8 Table 2.1 summarises the increase in risk of
health problems associated with obesity.
psychosocial functioning.
Studies
consistently showed an inverse relationship
between body weight and both overall self-
2.9 The WHO estimates that globally approximately
esteem and body image among adolescents.15
58% of diabetes mellitus, 21% of ischaemic heart
Overweight in adolescence may also be
disease and 8 to 42% of certain cancers are
associated with social and economic
2 1
attributable to BMI greater than 21 kg/m .
problems in adulthood.14
Psychosocial Problems
2.10 Obesity is associated with a number of
Deaths
2.13 The death rate increases with rising degree
psychosocial problems including body shape
of overweight, as measured by BMI. The
dissatisfaction and eating disorders. People
increase in death rate with rising BMI is
with obesity are often confronted with social
steeper for both men and women under the
bias, prejudice and discrimination.14
age of 50. Moreover, the overweight effect
persists well into the ninth decade of life.16-18
2.11 The mechanisms leading to impaired
The death rate increases greatly at a BMI
psychological well-being are different from
above 30kg/m2 (Chart 2.1).19 Studies for all
those leading to physical illness. It is
adults implied a similar relationship between
important to acknowledge that undesirable
BMI and risk of mortality.2
psychosocial consequences of obesity are
derived from labelling effect that regards
fatness as “unhealthy” and “ugly”.
Childhood and Adolescence Obesity
2.14 Studies have shown a tendency for obese
children to remain obese in adulthood. 21
9
2.12 A common consequence of obesity in
Childhood obesity is also associated with
childhood and adolescence relates to
elevated r isk factors for cardiovascular
Tackling Obesity: Its Causes, the Plight and Preventive Actions
Why should we be concerned about obesity?
Chart 2.1
Relationship between BMI and relative risk of mortality 20
Average risk
Moderate risk
High risk
2.5
Relative risk
2.0
1.5
1.0
0.5
20
25
30
35
BMI
dyslipidaemia, insulin resistance and elevated
Economic Costs
2.17 Overweight and obesity, together with their
fasting glucose; all these factors can continue
associated health problems, have substantial
diseases such as raised blood pressure,
21-22
In particular, childhood
economic impact on the health care system by
obesity is associated with early development
bringing about both direct and indirect costs.
of type II diabetes mellitus.
Direct costs refer to those incurred by the
into adulthood.
preventive, diagnostic and treatment services
2.15 Childhood obesity can lead to orthopaedic
related to overweight and obesity (for example,
complications due to excessive weight bearing
doctor consultations, hospitalisation and nursing
upon joints.2 The most serious conditions
home care). Indirect costs refer to the loss in
include slipped capital femoral epiphyses in
wages for people unable to work because of
which the hip joint is forced out of the
illness or disabilities as well as the loss in future
alignment, and bone growth deformities such
earnings caused by premature death. Little data
as Blount’s disease.
are available for quantifying the economic
consequences of obesity in Asian countries.
2.16 Obstructive sleep apnoea is another important
complication of childhood obesity and can
Obesity not only causes human sufferings from ill
lead to hypoventilation, daytime sleepiness
health, but also creates significant economic burden
2
and in rare cases, sudden death.
to the society. Direct economic costs of obesity
assessed in several developed countries are in the
range of 2 to 7% of total health care costs.2
Tackling Obesity: Its Causes, the Plight and Preventive Actions
10
Chapter 3
How common is obesity?
Global Situation
3.1 The WHO estimated that more than one billion
Obesity in Hong Kong
3.4 The severity of the problem of obesity in Hong
adults are overweight and at least 300 million
Kong has not yet reached that in developed
of them are clinically obese which is defined
countries such as the US. Table 3.1 shows the
by BMI greater than or equal to 30. Moreover,
percentage of overweight and obesity in Hong
childhood obesity is already epidemic in some
Kong from a local study conducted in 1995 to
areas and on the rise in others. Around 22
1996.29 The prevalence of overweight and
million children under five are estimated to be
obesity was also found to increase with age in
23
overweight worldwide.
women. Nearly 50% of women aged above 45
were overweight and nearly 10% of them were
3.2 The prevalence of obesity is rising rapidly in
obese. For men, however, the prevalence of
developed countries. In the US, the UK and
overweight and obesity was similar among
Japan, the prevalence of adult obesity has nearly
different age groups.
doubled or even more since the 1980s. 2;24-26 A
similar trend is also seen in adolescents.27-28
3.5 A telephone survey commissioned by the
Department of Health (DH) was conducted in
3.3 In general, obesity is more prevalent in urban
early 2003 to assess the prevalence of overweight
than in rural areas. In developing countries,
and obesity, as well as related health behaviours.
obesity is more common in people of higher
Among 1,700 subjects aged 20 to 64, 19.7% of
socioeconomic status and in those living in
men and 13.8% of women were overweight,
urban areas. In developed countries, it is
while 23.4% of men and 12.7% of women were
common in people, especially in women, of
obese (Table 3.2).30 While the prevalence of
lower socioeconomic status, and among people
overweight and obesity are higher than that of
2
the study described in paragraph 3.4,29 it should
living in rural areas.
Table 3.1
Prevalence of obesity by gender in Hong Kong, 1995-199629
Classification
Underweight
Normal
Overweight
Obese
BMI (kg/m2)
Male
Female
< 20
9.2%
12.9%
20 - 25
52.8%
53.4%
25.1 - 30
32.6%
26.7%
> 30
5.4%
7.0%
Tackling Obesity: Its Causes, the Plight and Preventive Actions
12
How common is obesity?
be noted that the study conducted in 1995-
the obesity prevalence (BMI ≥ 30.0) in both
1996 was based on actual measurements. The
sexes (males 22.3%, female 20.0%).31
survey conducted in 2003 collected selfreported values for height and weight. The cut-
3.7 The same study showed that the prevalence of
off points for defining weight status differed
overweight and obesity generally increased with age
between the two studies as well.
(Chart 3.1). In males, the problem was most prevalent
among those aged 55-64 (55.4%), followed by those
3.6 The Population Health Survey 2003/2004
aged 45-54 (52.7%) and 35-44 (51.2%). In females,
commissioned by the Department of Health
the prevalence was highest among those aged 55-64
(DH) estimated that 17.8% of the population
(53.9%). The prevalence decreased for both males
aged 15 and above were overweight and 21.1%
and females who are aged 75 and above. However, as
were obese (Table 3.3). Overall, overweight
mentioned in section 1.10, the reduced lean muscle
was more common among males than females
mass in elderly may lead to underestimation of the
(20.1% vs.15.9%). Similar trend was found for
degree of overweight.31
Table 3.2
Prevalence of obesity by sex in Hong Kong, 2003 (self-reported data)30
BMI (kg/m2)
Male
Female
Overall
< 18.5
8.2%
15.8%
12.5%
Normal
18.5 - 22.9
48.7%
57.7%
53.7%
Overweight
23.0 - 24.9
19.7%
13.8%
16.4%
Obese
Above 25.0
23.4%
12.7%
17.4%
Classification
Underweight
Table 3.3
Prevalence of obesity by sex in Hong Kong 2003/2004 (provisional data)31
BMI (kg/m2)
Male
Female
Overall
< 18.5
7.8%
12.4%
10.3%
Normal
18.5 - 22.9
46.8%
48.8%
47.9%
Overweight
23.0 - 24.9
20.1%
15.9%
17.8%
Obese
Above 25.0
22.3%
20.0%
21.1%
–
3.0%
2.9%
3.0%
Classification
Underweight
Unknown/ missing
13
Tackling Obesity: Its Causes, the Plight and Preventive Actions
How common is obesity?
Prevalence of obesity (%)
Chart 3.1
Prevalence of overweight and obesity (BMI ≥23) by age group and sex in Hong Kong, 2003/200431
60%
50%
40%
Female
Male
Total
30%
20%
10%
0%
15-24
25-34
35-44
45-54
55-64
65-74
75+
Age (Years)
Prevalence of childhood obesity
Chart 3.2
Prevalence of childhood obesity in primary schools by gender and school year in Hong Kong, 1997-200232
25%
Male
20%
Female
Total
15%
10%
5%
0%
97/98
98/99
99/00
00/01
01/02
Year
Prevalence of childhood obesity
Chart 3.3
Prevalence of childhood obesity in secondary schools by gender and school year in Hong Kong, 1997-200233
25%
Male
20%
Female
Total
15%
10%
5%
0%
97/98
98/99
99/00
00/01
01/02
Year
Tackling Obesity: Its Causes, the Plight and Preventive Actions
14
How common is obesity?
3.8 The Student Health Service of the DH found
of males and 9.8% of females had diabetes
that the prevalence of obesity among local
mellitus (either already on medication to
pr imary and secondary school students
treat diabetes or had a glucose level
increased gradually from 12.1% in 1997/1998
≥11.1mmol/L after a 75g oral glucose
to 14.1% in 2000/2001, and dropped slightly
tolerance test); another 14.2% of males and
afterwards using the definition of obesity as
17.1% of females had impaired glucose
having a weight > median weight for height x
tolerance which was an early sign of
120%. The problem was more serious in
diabetes mellitus (plasma glucose level two
primary school students than in secondary
hours after the 75g glucose load was in
school students. The prevalence remained
range 7.8-11.0mmol/L).29
higher among boys with the difference
between boys and girls widening slightly over
the years (Charts 3.2 and 3.3).
32-33
Dietary Habits and Physical Activity
of Hong Kong People
Dietary habits
Obesity Related Diseases in Hong Kong
3.9 The majority of obesity-related diseases are
3.12 Healthy Living Survey 2001 found that only
multi-factorial. Given the strong association
at least twice a day and only 49% consumed
between increasing BMI and type II diabetes
vegetables at least twice a day. The mean
mellitus, cardiovascular and cerebrovascular
quantity of daily fr uit and vegetable
diseases, it is reasonable to attribute a significant
consumption for those who ate fruit or
proportion of these diseases to obesity.
vegetable at least once a day was 1.4 fruit and
21% of adult respondents consumed fresh fruit
1.2 bowls. Only 3% of respondents consumed
3.10 Heart diseases (coronary heart disease being the
major component) and cerebrovasular diseases
high-fat food at least once a day and 10% ate
all visible fat in their food.35
account for 14.6% and 9.5% respectively of the
total deaths in 2003 in Hong Kong.34
3.13 A telephone survey commissioned by the DH
in 2004 estimated that the daily average
3.11 A local prevalence study of 2,800 adults aged
consumption of fruits and vegetables was 3.3
25 to 74 in 1995/1996 found that 1 in 10
servings per person and less than one in five
men and 1 in 9 women had definite
(17.7%) of respondents reported consuming
hypertension (systolic blood pressure (SBP)
five or more servings of fruits and vegetables
≥160mm/Hg and/or diastolic blood pressure
per day. Females (21.3%) were more likely than
(DBP) ≥95mmHg), and 1 in 12 men and 1
males (13.8%) to consume five or more servings
in 16 women had borderline hypertension
of fruits and vegetables per day. In females,
(SBP 140-159mm/Hg and/or DBP 90-
the proportion who consumed five or more
29
94mmHg). The study also found that 9.5%
15
Tackling Obesity: Its Causes, the Plight and Preventive Actions
servings of fruits and vegetables per day
How common is obesity?
increased with age, from 15.2% for those aged
3.16 The Population Health Survey in 2003/2004
18-24 to 38.2% for those aged 55-64. In males,
commissioned by the DH estimated that
the proportions were the lowest in the 35-44
33.3% of the Hong Kong population aged
age group and the highest for those aged 55-64
15-64 (33.0% for males and 33.5% for
36
(11.2% and 17.3% respectively).
f e m a l e s ) we re p hy s i c a l l y i n a c t ive.
Comparatively, the 25-34 age group was the
Low intake of fruits and vegetables is estimated
mostly sedentary age group (37.9%), followed
to cause about 19% of gastrointestinal cancers,
by the 35-44 age group. Analyzed by
31% of ischaemic heart disease and 11% of stroke
occupation, the mostly sedentary occupation
worldwide. The WHO recommends 400 g daily
was clerks (42.8%).31
intake of fruits and vegetables for adults per day
for the prevention of chronic diseases such as heart
The recommendation for individuals to accumulate
diseases, cancer, diabetes and obesity.37
at least 30 minutes of moderate-intensity physical
activity on most days is largely aimed at reducing
Physical activity
cardiovascular diseases and overall mortality.The
3.14 In Hong Kong, sedentary lifestyle is prevalent
amount needed to prevent unhealthy weight gain
among the local population and television
is uncertain. Recommendation made by consensus
viewing is a very popular pastime. A survey
during two international conferences stated that
found that more than 80% of children
about 45 to 60 minutes of moderate-intensity
watched TV at leisure time, while only 33%
physical activity is needed on most days or every
chose to exercise.38 Moreover, nearly half of
day to prevent unhealthy weight gain.37
the children (45%) watched TV for over 3
hours per day. In 2001, Hong Kong people
on average spent 2.4 hours daily on watching
television,35 although this figure is 18 minutes
less than that noted in 1999.39
3.15 A survey conducted in 2001 found that 55%
of local adults had done exercise within the
previous month. Around 40% and 12% of
these respondents exercised 1 to 7 times and 8
to 11 times respectively within the preceding
month for duration of over 30 minutes each
time.35 Another study conducted in 2001
showed that children in Hong Kong exercised
less than those in other developed countries.40
Tackling Obesity: Its Causes, the Plight and Preventive Actions
16
Chapter 4
Who are at risk?
4.1 Obesity results from an imbalance between
members of the same family also share the same
energy intake and energy expenditure. Energy
diet and similar lifestyle which contribute to
derived from food is used to sustain body mass,
obesity.
to fuel metabolic functions and to perform
physical activity. When we take in more dietary
Ethnic origin
energy than we can consume, the excess is
4.5 Certain ethnic groups are more susceptible
to the development of obesity and its
stored in the body as fat.
complications, and the effects become
Biological Factors
apparent when the individuals are exposed
Age
to a more affluent lifestyle. For the majority,
4.2 In general, obesity in both sexes becomes more
t h i s p ro bl e m s e e m s t o re s u l t f ro m a
prevalent as age increases up to at least 50 to 60
combination of genetic tendency and a
41
years old. The older population has a higher
change from a traditional to a more affluent
tendency of being overweight or obese because
and sedentary lifestyle and its accompanying
of the decreased lean muscle mass, metabolic
dietary pattern.2
rate and physical activity that occur along with
the ageing process.
Biological factors may help to explain why obesity
occurs in certain individuals but not the others.
Sex
These irreversible factors are relatively less
4.3 Women generally have higher rates of obesity
2
important than the reversible ones such as
while men have higher rates of overweight. It
nutrition and physical activity, from the health
is widely recognised that women usually have a
promotion point of view.
higher percentage of body fat and a lower resting
metabolic rate than men, which may predispose
women to obesity. The difference of obesity
prevalence in women and men may also be
Nutrition
4.6 Modern diet has changed from one consisting
attributed to their difference in hormonal
of more complex carbohydrates, whole grains
regulation and fat metabolism which are not
and fibres to one with high animal fats and
fully understood.
proteins, refined carbohydrates, sugars and few
fruits and vegetables.
Genetic susceptibility
4.4 Obesity tends to run in families. The risk of
4.7 Taking into account all developing countries,
developing obesity is one- to two-fold for the
the per capita consumption of meat and dairy
first-degree relatives of an overweight person,
products rose by an average of 50% per person
and about two- to three-fold for those of an
between 1973 and 1996.43 Traditional cuisines
obese person.42 While genes influence weight,
and homemade food are increasingly saving
Tackling Obesity: Its Causes, the Plight and Preventive Actions
18
Who are at risk?
naturally present in honey,
syrups and fruit juices”,
increase the energy density
of diet without providing
much specific nutrients and
result in a positive balance
of total energy intake. In
the expert consultation
commissioned by the
WHO, and the Food and
Agriculture Organization
(FAO) in 2003, a set of
guidelines was developed as
population nutrient intake
goals for the prevention of
diet-related chronic diseases
replaced by high-fat, energy-dense fast foods
such as cardiovascular diseases, cancers, diabetes
and soft drinks.
and obesity. One recommendatio n is that
consumption of free sugars should not exceed
4.8 People choose energy-dense, nutr ient-
10% of total energy intake.37
poor fast foods because they are cheap,
t a s t y, w i d e l y p ro m o t e d a n d r e a d i l y
4.10 Eating habit has a bearing on the development
available. Energy-dense foods tend to be
of obesity. Skipping breakfast may lead to
high in fat (such as butter, oil and fr ied
over-consumption later in the day.44 Besides,
foods), sugar or starch, while energy-
those who eat out more, on average, have a
dilute foods have high water content (such
higher BMI than those who eat at home more
a s f r u i t s a n d ve g e t a b l e s ) . T h e r e i s
often.44-45
convincing evidence that a high intake of
energy-dense foods induces weight gain,
whereas a high dietary fibre intake helps
protect against weight gain. 37
Physical Activity
4.11 Studies have revealed an inverse relationship
between BMI and physical activity. 46-49
People in developed countries lead a more
19
4.9 There are evidences suggesting that free sugars,
sedentary lifestyle because of increasing use
which are defined as sugars “added to foods by
of public transport coupled with affordability
manufacturer, cook or consumer, plus sugars
of cars, automation of work, use of labour-
Tackling Obesity: Its Causes, the Plight and Preventive Actions
Who are at risk?
devices both at home and at work, and more
activity patterns have overwhelmed our
sedentary leisure pursuits such as TV viewing.
body’s regulatory processes that keep weight
50
stable in the long term.
The global estimate for the prevalence of
physical inactivity among adults is 17%.
Estimates for prevalence of some, but
Obesity is not just a problem of the individual.
insufficient physical activity (<2.5 hours per
It is a population problem and should be tackled
week of activities of moderate intensity) range
as such.
from 31% to 51%.
51
4.12 It is suggested that a total of one hour per
Micro-environments
day of moderate intensity activity, such as
Home environment
brisk walking, on most days of the week is
4.15 The home environment is the most important
needed to maintain a healthy body weight,
setting in shaping children’s eating behaviours
particularly for people with sedentary
and physical activity patterns which may
occupations.
42
promote the development of obesity. It has
been shown that food consumption by
Regular exercise raises the resting metabolic rate.52
children is influenced by the food availability
People who perform regular moderate levels of
and accessibility, parents’ nutr ition
physical activity increase their capacity to utilise
knowledge, attitudes and practices, TV
fat.53
viewing and child-parent interactions
concerning food. For example, using foods
as rewards and restricting access to foods
Environmental Factors
4.13 The rapid increase in obesity rate over recent
increase children’s preferences for and intake
of those foods.54-57
years has occurred in too short a time for
significant genetic changes to take place
within populations. This suggests that the
rapid global rise in obesity is likely attributable
to a changing environment that causes overconsumption of food and promotes a
sedentary lifestyle.
4.14 Environmental and social factors exist to
influence individual lifestyle and behaviours.
Their effects on food intake and physical
Tackling Obesity: Its Causes, the Plight and Preventive Actions
20
Who are at risk?
School environment
TV advertisement
4.16 Schools are the key setting for influencing
4.18 Fast food restaurants and energy-dense foods and
children’s behaviour. Hence, tackling obesity-
drinks are among the most advertised products
promoting elements in schools is important to
on television. These
prevent childhood obesity. For example, soft
commercials are often
drink vending machines are increasingly
targeted at children.
available in schools. A study has shown that
M o r e ove r, t h e
excessive consumption of high-sugar soft
amount of TV
drinks is associated with obesity in children.
58
viewing
was
associated with
Fast food restaurants
children’s demand for
4.17 Fast food outlets which provide high-fat,
the highly advertised
energy-dense foods and soft drinks are
foods.60
increasingly popular throughout the world.
An average fast food restaurant meal provides
Macro-environments
1,000-2,000 kilocalories, i.e., up to 100% of
Socio-economic environment
the recommended daily intake for adults, and
4.19 Obesity is more prevalent in individuals with
59
Their
high socio-economic status (SES) in
popularity is further enhanced by mass
developing countries than individuals with
advertising and low price.
low SES in developed countr ies. In
the portion size is also increasing.
developed countries, high SES protects
people from becoming obese as these
individuals are better educated and live in
less obesity-promoting environment with
more physical recreational facilities and less
fast food outlets.61 They are thus more likely
to follow dietary guidelines, eat healthily and
engage in physical activity.
Urbanisation
4.20 With urbanisation, food is more abundant and
TV penetration is increased. With more
women working, the demand for high-fat,
energy-dense and low-nutrient ready-to-eat
food and labour-saving devices such as
washing machine is increased. Also, less time
21
Tackling Obesity: Its Causes, the Plight and Preventive Actions
Who are at risk?
is allocated to cooking. All these have
in the last three decades. A slim figure in
profound effects on the dietary habit and
women has come to symbolise competence,
physical activity level of the population.
success, control and sexual attractiveness,
while obesity represents laziness, self-
Cultural environment
indulgence and a lack of will power.2 These
4.21 Throughout most of human histor y,
values are reinforced by television and popular
increased weight has been viewed as a sign
magazines 62-63 that lure people to adopt
of health and wealth. This is still the case in
unhealthy weight control practices such as
many cultures, especially where conditions
inappropriate dieting, which very often
make it hard to gain weight or where
results in weight cycling, eating disorders and
thinness in babies is associated with increased
failure to achieve weight goals.64-66 Men do
risk of infectious diseases.2
not generally recognise being overweight or
obese as a problem. This phenomenon raises
4.22 On the other hand, in many industrialised
concern because men are more at risk of
countries, there has been a marked change
abdominal fat accumulation and yet tend to
in the expectation of body shape and weight
ignore it.2
Tackling Obesity: Its Causes, the Plight and Preventive Actions
22
Chapter 5
Initiatives to prevent
overweight and obesity
5.1 This section will discuss the initiatives which
growth and development of infants. 67 It is
aim at preventing overweight and obesity mainly
recommended that inf ants should be
through lifestyle measures, chang ing
exclusively breastfed for the first 6 months of
environment and setting policy. Literature
life to achieve optimal growth, development
review was conducted by means of EBSCO
and health.68
research database. Initiatives quoted in several
obesity prevention review papers are also
5.5 There is growing evidence suggesting that
included in this section. Both initiatives either
breastfeeding can prevent subsequent childhood
with or without BMI/body weight change as
overweight and that longer breastfeeding period
the outcome measurements are covered. For
gives greater protection for children though the
example, studies aiming at increasing intake of
mechanism of this protection is not clear.69-72
fruits and vegetables and decreasing sedentary
Besides, breastfeeding has a lot of other benefits
activities are also included. However, specific
to mothers and children. The continued
treatments for obesity (e.g., drug treatment,
protection, promotion and suppor t of
surgical treatment) are excluded. A life-course
breastfeeding remain a major health priority.
approach is adopted to summarise the initiatives
to prevent overweight and obesity.
5.6 The US Government has included breastfeeding
as a key objective in its national prevention
Infancy
5.2 Infancy is an important stage of growth and
agenda - Healthy People 2010. The agenda
development. During infancy, nutrition is the
75% during early postpartum period, 50% at 6
most important factor that affects growth of
months and 25% at 1 year by 2010.73
aims to attain a breastfeeding rate of at least
infants. Therefore, this stage plays a key role
in controlling obesity. The level of physical
5.7 Three types of initiatives have been shown to
activity of infants should normally be within
be useful in promoting breastfeeding when
a limited range.
delivered as a single initiative. They include
small group health education, peer support
5.3 Infancy is also a stage of dependency. Parents
programmes and one-to-one health education.
and carers are the key providers of nutrition for
Packages of initiatives have also been shown to
infants. Hence, it is important that they choose
be effective at increasing the initiation and, in
suitable food for infants in order to maintain
most cases, extending the duration of
their normal growth and development.
breastfeeding in developed countries. Effective
packages include a peer support programme
Breastfeeding
and/or a media campaign combined with policy
5.4 The WHO recommends breastfeeding as the
changes in the health sector.74
way of providing ideal food for the healthy
Tackling Obesity: Its Causes, the Plight and Preventive Actions
24
25
Initiatives to prevent overweight and obesity
5.8 The WHO and the United Nations Children’s
5.9 Breastfeeding rate in Hong Kong is still relatively
Fund (UNICEF) launched the Baby-Friendly
low but a rising trend has been noted since
Hospital Initiative (BFHI) in 1991 as a key
1991.78 A local study found that from 1987 to
strategy for promoting breastfeeding.75 Under
1997, the breastfeeding initiation rate increased
the BFHI, hospitals and maternity facilities can
by 6.7% (from 26.8% to 33.5%).79 Moreover,
be designated “baby-friendly” when they do not
the rate of breastfeeding for more than 3 months
accept free or low-cost breastmilk substitutes,
increased from 3.9% in 1987 to 10.3% in 1997.
feeding bottles or teats, and have implemented
Annual breastfeeding surveys conducted by the
the “Ten Steps to Successful Breastfeeding”
DH reveal that both the prevalence and the
76
Moreover, the WHO and the
duration of breastfeeding in Hong Kong have
UNICEF have jointly developed the
increased since 1997. The percentage of babies
“International Code of Marketing of Breastmilk
ever breastfed increased from 50% in 1997 to
Substitutes” to guide appropriate marketing
62% in 2000.78
(Table 5.1).
practices and to protect breastfeeding
(Table 5.2).77
Table 5.1
Ten steps to successful breastfeeding76
Every facility providing maternity services and care for newborn infants should:
1.
Have a written breastfeeding policy that is routinely communicated to all health care staff.
2.
Train all health care staff in skills necessary to implement this policy.
3.
Inform all pregnant women about the benefits and management of breastfeeding.
4.
Help mothers initiate breastfeeding within half an hour of birth.
5.
Show mothers how to breastfeed, and how to maintain lactation even if they should be separated
from their infants.
6.
Give newborn infants no food or drink other than breast milk, unless medically indicated.
7.
Practise rooming-in - that is, allow mothers and infants to remain together - 24 hours a day.
8.
Encourage breastfeeding on demand.
9.
Give no artificial teats or pacifiers (also called dummies or soothers) to breastfeeding infants.
10. Foster the establishment of breastfeeding support groups and refer mothers to them on discharge
from the hospital or clinic.
25
Tackling Obesity: Its Causes, the Plight and Preventive Actions
Initiatives to prevent overweight and obesity
Table 5.2
Summary of the International Code of Marketing of Breastmilk Substitutes77
The Code includes these 10 important provisions:
1.
No advertising of all breastmilk substitutes* to the public.
2.
No free samples to mothers.
3.
No promotion of products in health care facilities, including no free or low-cost formula.
4.
No company representatives to contact mothers.
5.
No gifts or personal samples to health workers. Health workers should never pass products on to
mothers.
6.
No words or pictures idealizing artificial feeding, including pictures of infants, on the labels.
7.
Information to health workers must be scientific and factual.
8.
All information on artificial infant feeding must explain the benefits and superiority of breastfeeding,
and the costs and hazards associated with artificial feeding.
9.
Unsuitable products, such as sweetened condensed milk should not be promoted for babies.
10. Manufacturers and distributors should comply with the Code’s provisions even if countries have
not acted to implement the Code.
* Breastmilk substitutes include: infant formula, follow-up formula, feeding bottles, teats, baby food and beverages etc.
5.10 Various efforts have been made to promote
7th of August), the DH organised a publicity
breastfeeding in Hong Kong. Since the early
campaign to raise public awareness of
1980s, a designated team has been set up by
breastfeeding in 2003 and 2004 (Diagram 5.1
the former Medical and Health Department
and 5.2).
to promote breastfeeding. Promoting work
includes running antenatal classes at Maternal
and Child Health Centres and public hospitals
Diagram 5.1
An advertisement of promoting
breastfeeding in MTR station in 2003
for expectant mothers, visiting postnatal wards
and providing counselling and active support
for those who chose to breastfeed. In 2000,
the Family Health Service of the DH
formalised the existing breastfeeding guidelines
into a written breastfeeding policy.80 The main
points in the “Ten Steps to Successful
Breastfeeding” and the “International Code of
Marketing of Breastmilk Substitutes” have been
incorporated into the policy. In support of
the annual World Breastfeeding Week (1st to
Tackling Obesity: Its Causes, the Plight and Preventive Actions
26
Initiatives to prevent overweight and obesity
Diagram 5.2 Promoting breastfeeding - Baby Expo 2003
dur ing childhood and adolescence is
associated with obesity in adulthood. 82-83
A study reported that obese children will
have a risk as high as 80% of developing
adult obesity (BMI > 28) when they are 35
years old. 84
5.13 School-based programmes for obesity
prevention are attractive for several reasons,
including the large amount of contact time
with school children; the utilisation of the
existing organisational, social and
communication structures; and the ability
Childhood and Adolescence
5.11 Childhood and adolescence are the stages of
to reach a large percentage of children in
maximal physical development. Both
been controversies about banning the sale
nutrition and physical activity are crucial for
of unhealthy food and drinks in schools.
normal development, as well as the prevention
However, increasing the availability of more
of overweight and obesity in children and
healthy food and dr inks in schools,
adolescents. Unlike infants, the nutritional
especially at lower prices, could be an
intake of children and adolescents is only
alternative.86
the population at a low cost.85 There have
partially controlled by their parents. Many
of them purchase snacks and lunch
5.14 Many school-based obesity preventive
themselves. Thus, health education is
prog rammes do not target at obesity
important to increase their knowledge and
specifically but rather at reducing risk factors
alter their attitudes towards healthy eating.
of non-communicable diseases (NCD) such
On the other hand, nutritional adequacy for
as cardiovascular diseases and diabetes. Such
normal growth and development must be
programmes focus on improving diet and
ensured in any childhood obesity prevention
increasing physical activity level in general.
effort.
81
These initiatives generally include classroom
components that teach students about and
5.12 BMI begins to increase rapidly after a period
motivate them to acquire healthier habits.87-100
of reduced adiposity during preschool years.
These programmes are usually successful in
Children at the age of around 5 to 7 will
increasing healthy behaviours such as physical
easily get fat, a phenomenon known as
activity and consumption of fruits and
adiposity rebound.
27
2
Moreover, obesity
Tackling Obesity: Its Causes, the Plight and Preventive Actions
vegetables.
Initiatives to prevent overweight and obesity
5.15 Although obesity is common among school
three mechanisms: (1) reduced energy
children, it is not considered to be a top
expenditure due to the displacement of
priority in the school agenda. The issue of
physical activity by TV viewing, (2)
obesity has to compete with many other
increased energy intake from eating during
health issues, such as anti-smoking,
viewing or consuming extra food bought
sexuality and other non-health topics
after watching food advertisements, and (3)
including environmental protection, fire
decreased resting metabolic rate during
safety, etc.
101
viewing.105
5.16 The concept of health-promoting school is
5.18 Two school-based programmes aiming at
an extension of the Ottawa Charter for Health
reducing the amount of time spent on
Promotion initiated by the WHO in 1986.
sedentary behaviour showed a consistent and
In a health-promoting school, students are
sizable decrease in TV viewing among
encouraged to enjoy healthy school life,
children. One of these programmes showed
promote healthy living in their families and
a significant decrease in the participants’
102
communities, and protect their own health.
BMI, skinfold thickness, waist circumference
Different health education and promotional
and waist-to-hip ratio, 106 while the other
activities on various health topics, including
showed a 24% reduction in the prevalence
healthy lifestyles, are organised by the school
of obesity among girls but no change among
to create a healthy school environment that
boys. 107 These prog rammes included
facilitates the healthy development of students.
instructions in behavioural management
For example, a large-scale health promotion
techniques or strateg ies such as self-
campaign called “The Biggest Healthy
monitoring of viewing behaviour, limiting
Breakfast Day” was organised in 2002 to
access to TV and video games, and limiting
promote healthy eating habit to students,
the time for watching TV and playing video
parents and teachers.103
games.
M o re ove r, l e s s o n s o n s e l f -
monitoring and reduction of TV and video
School-based programmes to reduce sedentary activities
game usage were incorporated into the
5.17 Wa t c h i n g T V i s t h e m o s t c o m m o n
c u r r i c u l u m f o r s t u d e n t s . Pa r e n t a l
sedentary activity of children, which is one
involvement was also a prominent part of
of the most modifiable causes for obesity
the programme. Newsletters that were
in children. Young people have become
designed to motivate parents to help their
more physically inactive in the last 30 years,
children adhere to their time schedules and
largely because they spend much time
provide suggested strategies for limiting TV,
watching TV.
104
TV viewing is believed to
have caused obesity by one or more of the
videotape and video game use for the whole
family were distributed to parents.106
Tackling Obesity: Its Causes, the Plight and Preventive Actions
28
Initiatives to prevent overweight and obesity
School-based programmes on physical education (PE)
project, rope skipping, etc). The DH has also
5.19 School-based PE programmes promote physical
promoted physical activity in kindergartens
activity by modifying curricula or policies in
through the use of kid songs. Short-term results
schools. These programmes increase the amount
showed that over 60% of children continued to
of time students spent on moderate and/or
exercise 20 minutes each day for at least 20 days
vigorous activities. This can be done in a variety
after the programme.116
of ways, including having more PE classes,
lengthening existing PE classes, or increasing
School-based programmes on dietary modification
the intensity level of physical activity of students
5.22 Many school-based programmes advocate
dur ing PE classes without necessar ily
healthy eating as a means of preventing
lengthening class time. 108 Some schools
obesity. Increasing the intake of fruits and
encourage extracurricular activities such as sports
vegetables, and decreasing the amount of fat
days and outings to increase physical activity time
intake have been the main aims of many
and levels among students.
programmes. The WHO recommends that
the consumption of fruits and vegetables be
5.20 There is strong evidence that school-based
increased for both adults and children. Adults
PE is effective in increasing levels of physical
and children should consume at least five
activity and improving physical fitness among
servings of fruits and vegetables each day (for
students. However, BMI measurements
the definition of one serving size of fruits and
mostly show small decreases or no
vegetable, see Table 5.3).117 However, the
change.109-115 The varied results may be due
adoption of the recommended standard by
to limited efforts being put on dietary
the American children and adolescents has
education.115 However, increasing physical
been unsuccessful. A study showed that
activity levels can bring about many benefits,
among American children aged 6 to 11, only
such as reducing the risk of cardiovascular
16% of them ate 5 or more servings of fruits
diseases, diabetes and certain forms of cancers,
and vegetables per day.118
and improving musculoskeletal health.
Table 5.3 Definition of one serving size of fruit and vegetable119
5.21 Compared with other countries where daily PE
• 3/4 cup (6 oz.) 100 percent fruit or vegetable juice
Hong Kong generally allocate only two 35-
• 1/2 cup cut-up fruit
minute lessons per week to PE. To fill the gap,
• 1/4 cup dried fruit (e.g., raisins, apricots, mango)
the Education and Manpower Bureau (EMB)
• 1 cup raw, leafy vegetables
and other organisations have organised many
• 1/2 cup raw or cooked vegetables
school-based physical activity programmes
• 1/2 cup cooked or canned peas or beans
(e.g., morning exercise, comprehensive dance
29
• One medium fruit (e.g., apple, orange, banana, pear)
classes are recommended, primary schools in
Tackling Obesity: Its Causes, the Plight and Preventive Actions
Initiatives to prevent overweight and obesity
5.23 Educational programmes on nutrition have
s c h o o l s a n d “ H e a l t hy L u n c h We e k
been implemented worldwide and are
Competition” in secondary schools were
successful in increasing the knowledge of
conducted by the DH to promote healthy
healthy eating among students. Changes in
eating among students. The programmes
120-122
attitude and behaviour are noted.
aimed at increasing the knowledge of healthy
eating among teachers, parents, students and
5.24 School-based programmes aimed at educating
tuckshop operators, and improving the
students to reduce intake of carbonated drinks
availability of healthy food in schools.124-125 All
were shown to be effective. A cluster
of the three movements were co-organised
randomised controlled trial conducted in the
with non-governmental organisations (NGO)
UK found that consumption of soft drinks
and academic institutions. Healthy eating was
was reduced among the students by an
promoted through various channels, e.g.,
educational programme to discourage them
pamphlets, posters, exhibitions, health talks,
from consuming carbonated dr inks.
etc. Parents, teachers and tuckshop owners
Moreover, the percentage of overweight and
were involved. A teaching kit was developed
obese children decreased in the intervention
for each healthy eating movement to facilitate
group, compared with an increase in control
sustainability of the programme in schools.124-125
group.123
Similar programmes were also conducted in
kindergartens and nurseries to promote healthy
5.25 Similar programmes have been tried out in
birthday parties. All of these healthy eating
Hong Kong. Three movements, namely,
programmes had favourable short term results
“ H e a l t h y E a t i n g M ove m e n t ” f o r
in improving the knowledge of children, but
kindergartens/nurseries (Diagram 5.3),
they did not show any behavioural change in
“Healthy Tuckshop Movement” in primary
the eating habits of children.126
Diagram 5.3 “Healthy Eating Movement” for kindergartens and nurseries in 1999
Tackling Obesity: Its Causes, the Plight and Preventive Actions
30
Initiatives to prevent overweight and obesity
5.26 The EMB has incorporated teaching of
verbal advice, written materials, assessment,
healthy eating into the school curriculum.
etc.) concluded that the effect is uncertain.127
In primary schools, knowledge and correct
It was suggested in the review that single-
attitudes towards healthy eating are taught in
facet initiatives targeted to patients in primary
the General Studies curriculum. The teaching
care to address physical activity alone could
becomes more advanced in secondary schools.
not achieve significant results. The
In addition to learning the importance of a
programmes had to be incorporated into
balanced diet in the classes of biology, social
multi-faceted, community-wide strategies to
education and home economics, students also
become effective. However, examples to
explore the issue of obesity in their science
elaborate on details of such strategies were
and technology subjects.
not included.
Adulthood
5.27 Adulthood is a stage in which growth has been
Exercise prescription (Diagram 5.4) is a piece of
stabilised and degeneration gradually sets in,
to patients, like medication prescription. It
especially in late adulthood. Caloric intake
clearly indicates the type, frequency and duration
needs to be reduced as metabolic rate
of exercises that the patient needs to do.
advice on physical activity prescribed by doctors
decreases. In Hong Kong, adults are often
occupied with work and lack time for regular
Diagram 5.4 An example of exercise prescription
exercise. According to the 2001 Healthy
prescribed by doctors
Living Survey, around 45% of the respondents
had not exercised for at least 30 minutes in
the month before the study took place.35 This
lifestyle predisposed them to obesity.
Promoting physical activity in primary care settings
5.28 Doctors working in primary care settings are
ideally placed to provide health education to
the general adult population. They have the
opportunity to inform and influence patients
on measures that enhance health at a time
when patients are generally receptive to health
advice dur ing medical consultation.
However, a systematic review of the initiatives
to promote physical activity in primary care
settings (including exercise prescription,
31
Tackling Obesity: Its Causes, the Plight and Preventive Actions
Initiatives to prevent overweight and obesity
5.29 A randomised controlled trial on exercise
Workplace initiatives on physical activity and/or
prescription was conducted in 2003 by the
dietary modification
DH. General practitioners were recruited
5.31 Workplaces are ideal community settings to
from government and private clinics to
implement health promotion initiatives.
participate in the study. The results showed
They offer not only the ready access to a
that exercise prescription brought about
large proportion of the adult population who
significant changes in stage progression in
spend over half of the day there, but also the
Prochaska’s Stages of Change Model.
use of existing organisational structures for
However, concomitant changes in physical
delivering these initiatives.133
activity levels were not noted. This
indicates that the intervention could have
5.32 Workplaces initiatives to promote physical
an impact to motivate sedentary patients
activity are generally about providing easy
to exercise but the intensity is not strong
access to facilities (e.g. gymnasium) where
enough to bring about a change in physical
people can do exercise. 134-135 They also
activity level. Developing methods to
provide training and health education to
reinforce the programme used in this study
participants. 136-140 These programmes are
is a future challenge. Reinforcement can
effective in getting people to exercise more.
be provided by a conducive environment
O t h e r wo r k s i t e i n i t i a t ive s p rov i d e
for the patients to exercise or following up
comprehensive health promotion activities
the exercise prescription recommendations
to target behavioural risk factors such as low
by d o c t o r s i n s u b s e q u e n t m e d i c a l
level of physical activity and unhealthy diet.
consultations.
The prog rammes mainly consist of
workshops, educational classes, support
Tailor-made physical activity programmes
g ro u p s , e x h i b i t i o n s a n d s o m e t i m e s
5.30 Tailor-made physical activity programmes are
environmental modifications. These
designed to suit each participant’s interests and
programmes can effect a positive change of
preferences, and incorporate physical activity
lifestyle habits.
into daily routines. Programme components
usually include skills such as goal-setting and
Promoting physical activity using social support initiatives
self-monitoring of progress towards the
5.33 Programme sustainability is an important
128-132
These programmes are generally
consideration for effective promotion of
effective in increasing physical activity level
physical activity. This can be achieved
among both men and women, and in a variety
through social support, which is defined as
of settings.108 A decrease in body weight128
the presence of interpersonal liking, attraction
goal.
or percentage of body fat
some studies.
132
was reported in
and group cohesiveness among individuals
exercising together. Initiatives of social
Tackling Obesity: Its Causes, the Plight and Preventive Actions
32
Initiatives to prevent overweight and obesity
support include making a “contract” with
adults. Despite this, many old people remain
other participants to achieve specified levels
active and enjoy a good quality of life.
of physical activity or setting up walking
groups to provide companionship and
5.37 The 2001 Healthy Living Survey found that
support. Project staff will also phone
compared to younger adults, more older
participants to monitor prog ress and
people had exercised in the month prior to
encourage continuation of activities.108
the study.35 Older people had a participation
rate of 63.5%, which was higher than that of
5.34 Most social support initiatives are effective in
people aged 40 to 49 at 45.3%.
getting people to become more physically
active. 141-145 The programmes enhance
5.38 Older people usually do not engage in
participants’ fitness levels, knowledge about
vigorous exercise. Most of them prefer
exercise and confidence in exercising. These
stretching exercise or mild aerobic exercise,
initiatives are effective in various settings and
such as “morning walks” and Tai Chi. These
among adults of different sexes, ages and
exercises provide an opportunity for social
interests to exercise.
108
gatherings as well as benefiting their health.
To prevent obesity in elderly, physical activity
Commercial services or products for weight control
plays an equally important role as nutrition.
5.35 There are many commercial companies in
Hong Kong providing a range of services and
Nutritional education classes
products for slimming and maintaining
5.39 Group nutritional education classes are
“fitness”. Slimming has become a popular
commonly held in different settings, such as
trend in recent years. Many slimming or
elderly centres, clinics, etc. Many elderly acquire
beauty centres have been established in Hong
nutritional knowledge through these classes.
Kong. They claimed that they help clients
These classes provide a social environment for
reduce weight in a very short period of time.
the elderly, where their problems can be shared
However, most of these services and products
and addressed collectively. However, effects of
lack scientific evidence for their effectiveness
nutritional programmes on older people are
in weight loss or weight control.
inconclusive. For dietary practices, one study
showed no significant improvement,146 while
33
Old Age
5.36 From a physiological perspective, old age is
another study showed improvement in the short
the stage of degeneration. Because of the
the 6-month interval.147 However, there are
physiological changes associated with aging,
no standardised instruments currently available
elderly usually have slower and much more
that assess eating behaviours and nutrition
restricted range of movements than younger
knowledge in older adults.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
term though the effects were not maintained at
Initiatives to prevent overweight and obesity
5.40 The Elderly Health Services of the DH often
Physical activity groups (“morning walk”)
organise health talks and support groups for
5.41 “Morning walk” is popular in Hong Kong.
the elderly. Some of these activities are
Every morning, there are hundreds of small to
organised in collaboration with other
large groups of people (usually elderly)
community service units. The objectives of
gathering to do exercise. These groups are
the health talks are to motivate elderly to
organised by government organisations and
adopt healthy lifestyles and to increase their
NGOs, or initiated by the group members
health knowledge on common health
themselves. The types of exercise they do are
problems such as weight control. Support
mostly stretching exercises of mild to moderate
groups for weight reduction and healthy
intensity (e.g., Tai Chi). There are successful
eating are also organised.
overseas examples which have increased the
physical activity level (especially for walking)
among the elderly by using programmes such
as walking training sessions and personal
reinforcement by telephone follow-up.148-149
Tackling Obesity: Its Causes, the Plight and Preventive Actions
34
Initiatives to prevent overweight and obesity
General (all age)
loss rather than to health benefits. However,
Point-of-decision prompts to promote physical activity
the effects were mainly short-term. The
5.42 Point-of-decision prompts are signs placed
percentage of people using stairs dropped
near escalators and elevators to encourage
when the prompts were removed.150
people to use stairs for health benefits or
weight loss. This programme is shown to be
5.43 In 2003, the DH launched a point-of-
effective in various settings including subways,
decision prompts pilot programme to
train and bus stations, shopping malls,
promote stair use in selected public housing
university libraries, and among various
estates (Diagram 5.5). Twelve blocks were
population subgroups including men and
selected for the study, in which 9 were
women, both obese and not obese. 150-154
assigned as the intervention group and the
Studies showed that point-of-decision
remaining 3 as the control group.The results
prompts were effective in increasing the level
showed that the stair utility of the
of physical activity, as measured by an increase
intervention group increased from 2.9% at
in the percentage of people choosing to use
the baseline level to 3.5% 3 weeks after the
the stairs. More people would use the stairs
implementation of the programme. The
when these signs were posted. Tailor-made
increment was significant when compared
prompts to describe specific benefits or to
to that of the control group. Moreover, a
appeal to population subgroups may increase
survey found that both environmental and
the initiative’s effectiveness. For example, one
personal factors were cited as the major
study found that obese people used the stairs
enabling and disabling factors for the
more if the signs linked stair use to weight
respondents to use the stairs.155
Diagram 5.5 Posters and stickers of point-of-decision prompts in public housing estates
35
Tackling Obesity: Its Causes, the Plight and Preventive Actions
Initiatives to prevent overweight and obesity
Community-wide campaigns to reduce risk factors of non-
Campaign” in 2000 to promote regular
communicable diseases (NCD)
exercise to the public. This campaign
5.44 Over the last 20 years, several large-scale,
comprised both health education and a mass
community-wide and multi-component
media publicity programme.
programmes aiming at reducing the risk
factors for NCD like cardiovascular diseases
5.47 In 2001, 55% of the respondents of the
were conducted in many developed countries
Healthy Living Survey reported to have
including the US, Denmark, Finland, and so
exercised in the month prior to the study.
on. 156-162 The initiatives used in these
This figure is significantly higher than that
programmes adopted a multidisciplinary
found in 1999 (47%).35 However, whether
approach and required multisectoral
the increase is related to the campaign cannot
collaboration. Campaign messages were
be ascertained.
disseminated through mass media including
TV, radio, newspaper, mails , billboards and
5.48 The DH has also conducted other physical
advertisement to reach the target population.
activity campaigns of smaller scale targeting
Results showed that these campaigns were
special community groups, such as the
successful in increasing the level of physical
“Exercise with Your Neighbours” project.
activity of participants and changing their diet
The short-term results, such as increase in
towards healthy eating.
the proportion of active participants, were
found in the campaign.163
5.45 Community-wide educational campaigns
social networking in the community. These
Environment and Policy
5.49 Environmental and societal changes in recent
campaigns, however, require careful planning
years have improved the living standard of
and coordination, well-trained staff and
the population. Unfortunately, they have
sufficient resources for smooth
also brought about undesirable changes in
implementation. Poor planning and
the food supply and consumption.
insufficient resources generally result in ill-
Nowadays fast food and snacks which are
developed messages and weak campaigns that
high in fat and low in complex carbohydrates
are inadequate to achieve the “dosage”
are available almost everywhere in the world.
necessary to change the knowledge, attitude
A local study revealed that most of the fast
or behaviour of the people.
food available in Hong Kong contained too
may produce additional benefits of increasing
much fat, carbohydrate and cholesterol.164
5.46 The DH and the Leisure and Cultural
It is widely perceived that obesity has
Services Department of Hong Kong jointly
increased in industrialised society as people
launched the “Healthy Exercise for All
consume more fast food.2
Tackling Obesity: Its Causes, the Plight and Preventive Actions
36
Initiatives to prevent overweight and obesity
Reducing prices or increasing availability of healthy food
obesity. These drinks and foods contain
choices in vending machines or cafeterias
large amounts of calories and sugar. Some
5.50 In today’s schools, students can purchase
schools in the US have taken actions to limit
food from the tuckshops, vending machines
students’ access to unhealthy food. A school
and canteens. Several studies were
in San Francisco has banned the sales of
conducted to see whether changes in the
soft drinks and gradually replaced junk food
cafeterias and vending machines at schools
with healthy food choices in its student
and workplaces, including reducing the
cafe.169 Preliminary data showed that such
price or increasing the availability of healthy
actions did not bring financial loss to the
food, would increase healthy eating.86;165-168
school or complaints to the cafe. Moreover,
It was found that increasing availability of
the School Board of the Los Angeles
healthy food was associated with an increase
Unified School District planned to ban the
of healthy food sales, especially when the
sale of carbonated dr inks and other
food item was labelled as healthy. Some
nutrition-poor beverages in 2004.170 The
studies showed a two-fold to three-fold
new regulations will apply to all 677 schools
increase in purchase of healthy food when
within the district, with more than 700,000
the prices of these food were reduced by
students.
50%.86;166-167
5.52 At present, there is no compulsory regulation
37
Restricting sale of soft drinks and unhealthy snacks in
concerning the nutritional content of food
school tuckshops
sold at school tuckshops in Hong Kong. The
5.51 Consumption of soft drinks and unhealthy
EMB issued a set of guidelines on meal
snacks is a factor contributing to childhood
ar rangement to all schools in 2002
Tackling Obesity: Its Causes, the Plight and Preventive Actions
Initiatives to prevent overweight and obesity
(Table 5.4).171 The guidelines recommended
promoting unhealthy food in children and
school tuckshops to reduce the sale of
exposure affected food preference. Direct
unhealthy foods such as potato chips, candies
regulation on food advertisement is one way
and soft drinks. Instead, mineral water, low-
to tackle the problem. A more feasible
fat milk and healthy snacks such as fresh or
alternative is allotting equal amount of time
dried fruit and breakfast cereal are encouraged
to promoting nutrition messages.101
to be sold to students.
Tax on unhealthy food
Regulation on food advertisement for children
5.54 A study in the US found that taxes placed on
5.53 It has been estimated that an average American
unhealthy snacks and soft drinks. A number
child sees 10,000 food advertisements on TV
of the taxes which are now in effect, are
each year, and more than 90% of these
acceptable to consumers and could increase
advertisements are about sugared cereals, fast
general revenue. Some or all of the revenues
food, soft drinks and candies. 172 There is
collected are earmarked for special purposes,
evidence that their content aimed at
although not for nutritional programmes. For
Table 5.4
Items for sale at tuckshops (extract of guidelines on meal arrangements in schools)171
Items for Sale at Tuckshops
Schools should be careful in the choice of food items available for sale at the tuckshops as they directly
influence pupils’ eating habits. Schools should therefore consider the nutritional value of items to be
sold and advise staff and tuckshop operators to:
i.
reduce selling junk food such as potato chips and candies, which are of little nutritional value
other than fat and sugar;
ii.
sell mineral water and unflavoured and low fat milk, and reduced selling carbonated drinks;
iii. sell more healthy snacks such as fresh or dried fruit, soya milk, breakfast cereal, high fibre biscuits,
pre-packaged plain cakes, buns and sandwiches; and
iv. reduce selling food with overpackaging.
In addition, schools should not sell:
(1) items which involve too much preparation and washing up afterwards, e.g. noodles and porridge;
(2) items which are unsuitable for children, e.g. beer, alcoholic drinks and cigarettes; and
(3) items of cooked food which may easily be contaminated, e.g. fish meat balls, rich rolls and rice
dumplings.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
38
Initiatives to prevent overweight and obesity
example, one US state uses its soft drink tax
items on pre-packaged food. On the other hand,
revenue to support its medical, dental and
the UK manufacturers are required to specify
nursing schools.173
only 4 to 5 items on the label.
5.55 It is still unclear whether sales taxes have a
5.58 In Hong Kong, the Food and Environmental
significant effect on the sale and consumption of
Hygiene Department examined the feasibility
unhealthy food. The soft drink and snack
of nutrition labelling in Hong Kong. It is
industries oppose this suggestion and have
recommended that Hong Kong develop a
organised campaigns against special taxes on their
labelling scheme on nutritional information.
products. As a result, some states, cities or
The labelling system is proposed to be
counties, have reduced or repealed their snack
implemented in two stages. After an initial phase
taxes in recent years. One problem with taxing
of voluntary compliance, the phase of
unhealthy food is how to define “unhealthy
compulsory adoption will follow. Consultation
food”.173 Moreover, it is still not known how
was carried out in December 2003 to collect
high the taxes must be to affect consumption.101
comments and views from the general public
and the trade on the proposal (Diagram 5.6).177
Nutrition labelling
5.56 Nutrition labelling on pre-packaged food
Diagram 5.6 Consultation paper on labelling scheme
provides information about the nutrition
on nutrition information, issued by
composition, such as energy, protein,
Health, Welfare and Food Bureau in
carbohydrate, fat, and so on.
174
Nowadays,
consumers are more concer ned about
nutritional content of the food they purchased.
A local survey found that 65% of the
respondents read the nutrition labels on prepackaged food. Over 60% of the respondents
would buy healthier products (like low-fat,
cholesterol-free).175 However, suppliers of prepackaged food devote attention on attractive
packaging, rather than providing adequate
nutritional information for consumers.176
5.57 Different countries have different regulations on
nutrition labelling. Both Canada and the US
have strict regulations requiring manufacturers
to specify the amount of more than 10 nutrient
39
Tackling Obesity: Its Causes, the Plight and Preventive Actions
November 2003
Initiatives to prevent overweight and obesity
Working with the food industry
Students have to bring or purchase their
5.59 The co-operation of the food industry is
lunch and many of them order lunch boxes
essential in modifying eating behaviours in the
through their schools. A guideline on
society. However, choices of healthy food
choosing healthy lunch boxes has been
available in restaurants and markets are limited.
developed and disseminated to all schools by
There is an increasing interest to involve food
the EMB (Table 5.5).171
companies in promoting healthy products.
5.61 A summar y of the above-mentioned
5.60 Many half-day primary schools in Hong
Kong have changed to whole-day schools.
Table 5.5
initiatives to prevent overweight and obesity
can be found in Appendix 3.
Lunch box ingredients (extract of guidelines on meal arrangements in schools)171
Lunch Box Ingredients
The quality of lunch boxes depends very much on the choice of ingredients and the cooking methods
used. The following are some simple rules for choosing lunch boxes:
(1) The lunch boxes should be able to meet pupils’ nutritional and energy requirements.
(2) Lean meat and poultry without skin should be used. Leafy vegetables and fruit should always be
included.
(3) Grilled, steamed, boiled or baked food or stir-fried with less oil can lower the fat content.
(4) Fatty or highly processed food (e.g. deep fried food, sausages, canned luncheon meat) should be
avoided.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
40
Chapter 6
Recommendations
are associated with ill health. Many places are
Infancy
6.2 Breastfeeding promotion should remain a major
working hard to address this issue. As
health priority. Exclusive breastfeeding for the
highlighted in previous chapters, obesity and
first six months of life should be protected,
overweight are the result of energy imbalance
promoted and supported.
6.1 It is beyond doubt that obesity and overweight
with energy intake exceeding energy output.
approach to prevent and control the obesity
Childhood and Adolescence
6.3 School-based prog rammes for obesity
problem is to attain nutritional balance, that is,
prevention should produce the greatest effect
to limit energy intake from food consumption
because of the prolonged contact time with
and increase energy expenditure through
students in the school environment, utilisation
physical activity promotion or sedentary lifestyle
of the existing organisational, social and
reduction. At the societal level, however,
communication structures, and the ability of
obesity is no longer an issue requiring medical
the educational system to reach a large
solutions per se. It is a public health problem
proportion of children in the population at a
requiring solutions beyond the health sector.
low cost. That said, parental involvement stands
It is an issue best addressed through formulation
out as a prominent part of any successful school-
of healthy public policies, creation of supportive
based programme.
On the individual level, the logical and healthy
environments, enhancement of community
support, reorientation of health services, and
6.4 ‘Healthy eating’ should continue to be an
not least, development of personal skills.
integrated part of the school curriculum for
Furthermore, as risk factors for overweight
primary and secondary levels.
prevail, anti-obesity action must start early,
starting from infancy, through children and
6.5 Outside the school curriculum, successful
adolescence, to adulthood, and old age.
programmes that aim to increase physical activity
Recommended below are some health
level, promote consumption of fruits and
promotion actions found in the literature, which
vegetables, or reduce sedentary behaviours such
are considered more likely to yield positive
as watching TV and videotape, and playing video
health effects locally, especially when
games should be considered for implementation.
implemented in a well-planned, systematic and
coordinated manner. In connection with this,
6.6 Schools, including preschool institutions, should
the relevance of good surveillance data and
introduce school-based programmes such as kid
importance of programme evaluation cannot
songs for exercise, mor ning exercise,
be emphasised more, as these will help strategy
comprehensive dance projects, rope skipping,
formulation and determination of the best mix
etc. on top of regular physical education classes
of health promotion actions to deploy.
specified in the curriculum.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
42
Recommendations
6.7 Educational prog rammes on nutr ition,
6.12 Workplace initiatives that provide training and
including those teaching students to cut down
health education, participatory classes and
on intake of carbonated drinks, should be
environmental modifications should be
implemented, as they are shown to be effective
implemented to bring about positive changes
in improving the knowledge, attitude and
in lifestyles habits of employees.
behaviour of healthy eating among students.
6.13 Social support initiatives working through
6.8 Game-based experiential learning should be
peer groups, ‘contract-making’ and regular
considered for producing favourable short term
reminders are useful and should be used to
results on knowledge gain. Their effectiveness
encourage continuation of physical activity.
is optimised when coupled with other health
promotion actions.
Old Age
6.14 Group education commonly conducted in
Adulthood
6.9 Most adults are preoccupied with work. They
social or welfare settings should best be
are prone to develop a sedentary lifestyle marked
as walking, Tai Chi or stretching classes. Peer
by an unbalanced diet e.g. overeating, lack of
support should be promoted and encouraged.
combined with physical activity groups, such
fruits and vegetables, and high fat content from
acknowledge special circumstances of
Policy and Environment
6.15 Environmental modifications are conducive
individuals and make use of their social
to people’s choosing a healthy diet and taking
infrastructure should be considered for use.
part in regular physical activity. Everyone
processed food. Hence, measures that
has a part to play in creating this supportive
6.10 Doctors working in primary care settings have
environment. Large-scaled, well-planned
the opportunity to interact and influence a
community wide campaigns, supported by
large number of persons who are generally
social marketing means should be organised
receptive of health advice when they are ill.
to raise community awareness of the health
Every attempt should be made to counsel and
risks of overweight and obesity.
advise patients to consume a balanced diet
and undertake an increased amount of
physical activity.
6.16 Point-of-decision prompts, strategically
located in public premises and places, will
encourage more people to take the stairs
43
6.11 Health professionals should deploy skills such
instead of elevators and escalators. Building
as goal-setting and self-monitor ing to
managers should consider wider adoption of
encourage and support individuals in tailor-
this approach in helping to raise physical
made physical activity programmes.
activity levels of their users.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
Recommendations
6.17 Food sale outlets, such as school tuckshops
and canteens, and vending machines should
promotion initiatives for all ages to tackle
the obesity issue and its risk factors.
increase the availability of healthy food items
at cheaper prices.
6.22 New initiatives to be launched in 2005
include the stair climbing programme,
6.18 The education author ity and school
exercise prescription project,“2+3” campaign
administration are best placed to discourage
(to promote at least 2 servings of fruits and 3
sale of unhealthy food items e.g. candies,
servings of vegetables per day) and a school-
chips, soft drinks, to school children using
based research on fruit and vegetable
administrative measures. Parents and teachers
promotion.
should be mobilised to support this course.
6.23 O t h e r i m p o r t a n t d r ive s i n c l u d i n g
6.19 The food author ity should work more
breastfeeding promotion, the Healthy
closely with food suppliers and
Exercise for All Campaign and community-
manufacturers to promote a wider choice
based programmes are ongoing.
and consumption of healthy food products.
Specifically, introduction of nutr ition
6.24 The DH’s Central Health Education Unit
labelling on pre-packaged food will enable
re g u l a r l y l o o k s f o r a n d we l c o m e s
the consumers to make healthier choices
collaborative partnerships to promote
more easily.
population health. Support in the form of
surveillance data, research documents,
6.20 The impact and effectiveness of more
health promotion project planning,
innovative means of obesity control outside
implementation and evaluation advice and
Hong Kong, including regulation of food
joint action on innovative projects as
advertisements for children and imposition
appropriate can be offered.
of tax on unhealthy food, should be appraised
for their relevance and applicability to the
local situation.
Central Health Education Unit, DH
6.21 The Department of Health (DH) takes the
l e a d a n d wo r k s c l o s e l y w i t h o t h e r
g ove r n m e n t d e p a r t m e n t s , n o n g ove r n m e n t a l o r g a n i s a t i o n s , h e a l t h
professionals, academic institutions and the
community on a wide spectrum of health
Tackling Obesity: Its Causes, the Plight and Preventive Actions
44
50
References
1. World Health Organization. The world health report 2002: reducing risks, promoting healthy life. Geneva:
WHO; 2002.
2. World Health Organization. Obesity: preventing and managing the global epidemic. Report of a WHO
consultation on obesity. Geneva: WHO; 2000.
3. Garrow JS. Obesity and related diseases. London: Churchill Livingstone; 1988.
4. World Health Organization. The Asia-Pacific perspective: redefining obesity and its treatment. Sydney: Health
Communications Australia Pty Limited; 2000.
5. McKeigue PM. Metabolic consequences of obesity and body fat pattern: lessons from migrant
studies. In: Shetty P.S., McPherson K., editors. The origins and consequences of obesity. Chichester:
John Wiley & Sons; 1996.
6. Lean ME, Han TS, Morrison CE. Waist circumference as a measure for indicating need for weight
management. BMJ 1995; 311(6998):158-61.
7. Pouliot MC, Despres JP, Lemieux S, Moorjani S, Bouchard C, Tremblay A et al. Waist circumference
and abdominal sagittal diameter: best simple anthropometric indexes of abdominal visceral adipose tissue
accumulation and related cardiovascular risk in men and women. Am J Cardiol 1994; 73(7):460-8.
8. Ross R, Leger L, Morris D, de Guise J, Guardo R. Quantification of adipose tissue by MRI: relationship
with anthropometric variables. J Appl Physiol 1992; 72(2):787-95.
9. Lean ME, Han TS, Deurenberg P. Predicting body composition by densitometry from simple
anthropometric measurements. Am J Clin Nutr 1996; 63(1):4-14.
10. Han TS, Seidell JC, Currall JE, Morrison CE, Deurenberg P, Lean ME.The influences of height and age
on waist circumference as an index of adiposity in adults. Int J Obes Relat Metab Disord 1997; 21(1):83-9.
11. Leung SF. Hong Kong Growth Survey 1993. Hong Kong: The Chinese University of Hong Kong.
1996. Available at: http://www.cuhk.edu.hk/proj/growthstd/index.htm. Accessed 15 March, 2005.
12. Leung SS, Lau JT, Tse LY, Oppenheimer SJ. Weight-for-age and weight-for-height references for
Hong Kong children from birth to 18 years. J Paediatr Child Health 1996; 32(2):103-9.
13. Cole TJ, Bellizzi MC, Flegal KM, Dietz WH. Establishing a standard definition for child overweight
and obesity worldwide: international survey. BMJ 2000; 320(7244):1240-3.
14. Gortmaker SL, Must A, Perrin JM, Sobol AM, Dietz WH. Social and economic consequences of
overweight in adolescence and young adulthood. N Engl J Med 1993; 329(14):1008-12.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
46
References
15. French SA, Story M, Perry CL. Self-esteem and obesity in children and adolescents: a literature
review. Obes Res 1995; 3(5):479-90.
16. Lindsted K, Tonstad S, Kuzma JW. Body mass index and patterns of mortality among Seventh-day
Adventist men. Int J Obes 1991; 15(6):397-406.
17. Sidney S, Friedman GD, Siegelaub AB. Thinness and mortality. Am J Public Health 1987; 77(3):317-22.
18. Gordon T, Doyle JT. Weight and mortality in men: the Albany Study. Int J Epidemiol 1988; 17(1):77-81.
19. Jung RT. Obesity as a disease. Br Med Bull 1997; 53(2):307-21.
20. Manson JE, Willett WC, Stampfer MJ, Colditz GA, Hunter DJ, Hankinson SE et al. Body weight and
mortality among women. N Engl J Med 1995; 333(11):677-85.
21. Guo SS, Roche AF, Chumlea WC, Gardner JD, Siervogel RM. The predictive value of childhood
body mass index values for overweight at age 35 y. Am J Clin Nutr 1994; 59(4):810-9.
22. Must A, Jacques PF, Dallal GE, Bajema CJ, Dietz WH. Long-term morbidity and mortality of
overweight adolescents. A follow-up of the Harvard Growth Study of 1922 to 1935. N Engl J Med
1992; 327(19):1350-5.
23. World Health Organization. Global strategy on diet, physical activity and health. Obesity and overweight.
Facts. Available at: http://www.who.int/dietphysicalactivity/publications/facts/obesity/en/. Accessed
15 March, 2005.
24. Nutritional and Physical Activity Task Forces. Obesity: reversing the increasing problem of obesity in England.
London: Department of Health; 1995.
25. Health Survey for England 2003. London: Department of Health. Available at: http://www.dh.gov.
uk/assetRoot/04/09/89/14/04098914.pdf. Accessed 15 March, 2005.
26. Kuczmarski RJ, Flegal KM, Campbell SM, Johnson CL. Increasing prevalence of overweight among
US adults. The National Health and Nutrition Examination Surveys, 1960 to 1991. JAMA 1994; 20;
272(3):205-11.
27. Freedman DS, Srinivasan SR,Valdez RA, Williamson DF, Berenson GS. Secular increases in relative
weight and adiposity among children over two decades: the Bogalusa Heart Study. Pediatrics 1997; 99
(3):420-6.
47
Tackling Obesity: Its Causes, the Plight and Preventive Actions
References
28. Kotani K, Nishida M,Yamashita S, Funahashi T, Fujioka S, Tokunaga K et al. Two decades of annual
medical examinations in Japanese obese children: do obese children grow into obese adults? Int J Obes
Relat Metab Disord 1997; 21(10):912-21.
29. Janus ED, Cockram C, Fielding R, Hedley A, Ho P, Lam K et al. Hong Kong cardiovascular risk factor
prevalence study 1995-1996. Hong Kong: University of Hong Kong; 1997.
30. Kwok P, Tse LY. Overweight and obesity in Hong Kong - What do we know? Public Health &
Epidemiology Bulletin 2004; 13(4):53-60.
31. Department of Health. Population Health Survey 2003/2004 (provisional data). Hong Kong: Department
of Health; 2005.
32. Department of Health. Prevalence of childhood obesity in primary schools, 1997-2002. Hong Kong:
Department of Health.
33. Department of Health. Prevalence of childhood obesity in secondary schools, 1997-2002. Hong Kong:
Department of Health.
34. Department of Health. Annual Report 2003/2004. Hong Kong: Department of Health; 2005.
35. Lam TH, Chan B, Ho SY. A report on the Healthy Living follow-up survey 2001. Hong Kong; 2002.
36. Department of Health. Behavioral risk factor survey 2004. Hong Kong: Department of Health; 2005.
37. World Health Organization/ FAO consultation. Diet, nutrition and the prevention of chronic diseases.
Geneva: WHO; 2003.
38. The Boys’ & Girls’ Clubs Association of Hong Kong. Taipei, Hong Kong and Shanghai children’s living
survey; 2003.
39. Lam TH, Chan B, Ho SY, Chan SK. Report on Healthy Living Survey 1999. Hong Kong; 2000.
40. Hui SC, Chan CM, Wong SHS, Ha ASC, Hong Y. Physical activity levels of Chinese youths and its
association with physical fitness and demographic variables: The Hong Kong youth fitness study.
Research Quarterly for Exercise and Sport 2001; 72 (Supplement): A92-3.
41. International Agency for Research on Cancer. IARC handbooks of cancer prevention. Volume 6: Weight
control and physical activity. Lyon: IARC Press; 2002.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
48
References
42. Allison DB, Faith MS, Nathan JS. Risch’s lambda values for human obesity. Int J Obes Relat Metab
Disord 1996; 20(11):990-9.
43. The unfinished agenda: perspectives on overcoming hunger, poverty, and environmental degradation. Washington
(DC): International Food Policy Research Institute; 2001.
44. Holt S, Brand J, Soveny C, Hansky J. Relationship of satiety to postprandial glycaemic, insulin and
cholecystokinin responses. Appetite 1992; 18(2):129-41.
45. Binkley JK, Eales J, Jekanowski M. The relation between dietary change and rising US obesity. Int J
Obes Relat Metab Disord 2000; 24(8):1032-9.
46. Davies PS, Gregory J, White A. Physical activity and body fatness in pre-school children. Int J Obes
Relat Metab Disord 1995; 19(1):6-10.
47. Rising R, Harper IT, Fontvielle AM, Ferraro RT, Spraul M, Ravussin E. Determinants of total daily
energy expenditure: variability in physical activity. Am J Clin Nutr 1994; 59(4):800-4.
48. Schulz LO, Schoeller DA. A compilation of total daily energy expenditures and body weights in
healthy adults. Am J Clin Nutr 1994; 60(5):676-81.
49. Westerterp KR, Goran MI. Relationship between physical activity related energy expenditure and
body composition: a gender difference. Int J Obes Relat Metab Disord 1997; 21(3):184-8.
50. Ferro-Luzzi A, Martino L. Obesity and physical activity. In: Chadwick DJ, Cardew GC, editors. The
origins and consequences of obesity. Chichester: Wiley; 1996. 207-27.
51. World Health Organization. Global Strategy on Diet, Physical Activity and Health. Chronic disease information
sheets. Physical activity. Available at: http://www.who.int/dietphysicalactivity/publications/facts/obesity/
en/. Accessed 15 March, 2005.
52. Westerterp KR, Meijer GA, Schoffelen P, Janssen EM. Body mass, body composition and sleeping
metabolic rate before, during and after endurance training. Eur J Appl Physiol Occup Physiol 1994;
69(3):203-8.
53. Hurley BF, Nemeth PM, Martin WH, Hagberg JM, Dalsky GP, Holloszy JO. Muscle triglyceride
utilization during exercise: effect of training. J Appl Physiol 1986; 60(2):562-7.
54. Campbell K, Crawford D. Family food environments as determinants of preschool-aged children’s
eating behaviours: implications for obesity prevention policy: a review. Aust J Nutr Diet 2001; 58
(1):19-25.
49
Tackling Obesity: Its Causes, the Plight and Preventive Actions
References
55. Gibson EL, Wardle J, Watts CJ. Fruit and vegetable consumption, nutritional knowledge and beliefs in
mothers and children. Appetite 1998; 31(2):205-28.
56. Hearn MD, Baranowski T, Baranowski J. Environmental influences on dietary behaviour among
children: availability and accessibility of fruits and vegetables enable consumption. J Health Educ 1998;
29(1):26-32.
57. Skinner J, Carruth BR, Moran J, Houck K, Schmidhammer J, Reed A et al.Toddler’s food preferences:
concordance with family member’s preferences. J Nutr Educ 1998; 30:17-22.
58. Ludwig DS, Peterson KE, Gortmaker SL. Relation between consumption of sugar-sweetened drinks
and childhood obesity: a prospective, observational analysis. Lancet 2001; 357(9255):505-8.
59. Jacobsen MF, Nestle M. Halting the obesity epidemic: a public health approach. Public Health Reports
2000; 115: 12-21.
60. Taras HL, Sallis JF, Patterson TL, Nader PR, Nelson JA. Television’s influence on children’s diet and
physical activity. J Dev Behav Pediatr 1989; 10(4):176-80.
61. Subramania SV, Kawachi I, Kennedy BP. Does the state you live in make a difference? Multilevel
analysis of self-rated health in the US. Soc Sci Med 2001; 53(1):9-19.
62. Nemeroff CJ, Stein RI, Diehl NS, Smilack KM. From the Cleavers to the Clintons: role choices and
body orientation as reflected in magazine article content. Int J Eat Disord 1994; 16(2):167-76.
63. Silverstein B, et al.The role of the mass media in promoting a thin standard to bodily attractiveness for
women. Sex roles 1986; 14:519-32.
64. Craig PL, Caterson I.D. Body size, age, ethnicity, attitudes and weight loss. In: Alhaud G et al, editor.
Obesity in Europe. London: John Libbey; 1991. 421-6.
65. Craig PL, Swinburn BA, Matenga-Smith T, Matangi H,Vaughn G. Do Polynesians still believe that
big is beautiful? Comparison of body size perceptions and preferences of Cook Islands, Maori and
Australians. N Z Med J 1996; 109(1023):200-3.
66. Hamilton K, Waller G. Media influences on body size estimation in anorexia and bulimia. An
experimental study. Br J Psychiatry 1993; 162:837-40.
67. World Health Organization. Infant and young child nutrition. Global strategy on infant and young child
feeding. Fifty-fifth World Health Assembly provisional agenda item 13.10; 2002.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
50
References
68. Kramer MS, Kakuma R. Optimal duration of exclusive breastfeeding. Cochrane Database Syst Rev
2002; (1):CD003517.
69. Armstrong J, Reilly JJ. Breastfeeding and lowering the risk of childhood obesity. Lancet 2002; 359
(9322):2003-4.
70. von Kries R, Koletzko B, Sauerwald T, von Mutius E, Barnert D, Grunert V et al. Breast feeding and
obesity: cross sectional study. BMJ 1999; 319(7203):147-50.
71. Gillman MW, Rifas-Shiman SL, Camargo CA, Jr., Berkey CS, Frazier AL, Rockett HR et al. Risk of
overweight among adolescents who were breastfed as infants. JAMA 2001; 285(19):2461-7.
72. Dietz WH. Breastfeeding may help prevent childhood overweight. JAMA 2001; 285(19):2506-7.
73. U.S. Department of Health and Human Services. Healthy people 2010 online documents. USA; 2000.
Available at: http://www.healthypeople.gov/document/. Accessed 15 March, 2005.
74. Fairbank L, O’Meara S, Renfrew MJ, Woolridge M, Sowden AJ, Lister-Sharp D. A systematic review
to evaluate the effectiveness of interventions to promote the initiation of breastfeeding. Health Technol
Assess 2000; 4(25):1-171.
75. United Nations Children’s Fund. The baby-friendly hospital initiative. 2004. Available at: http://www.
unicef.org/programme/breastfeeding/baby.htm. Accessed 15 March, 2005.
76. World Health Organization. Evidence for the ten steps to successful breastfeeding. Geneva: WHO; 1998.
77. World Health Organization. International code of marketing of breast-milk substitutes. Geneva: WHO;
2004.
78. Khin PP, Cheung SL, Loh T. Support and promotion of breastfeeding: where are we now? Public
Health & Epidemiology Bulletin 2002; 11(3):25-32.
79. Leung GM, Ho LM, Lam TH. Breastfeeding rates in Hong Kong: a comparison of the 1987 and 1997
birth cohorts. Birth 2002; 29(3):162-8.
80. Department of Health. Breastfeeding policy. Hong Kong: Department of Health; 2004.
81. Schmitz MK, Jeffery RW. Public health interventions for the prevention and treatment of obesity.
Med Clin North Am 2000; 84(2):491-512.
82. Serdula MK, Ivery D, Coates RJ, Freedman DS, Williamson DF, Byers T. Do obese children become
obese adults? A review of the literature. Prev Med 1993; 22(2):167-77.
51
Tackling Obesity: Its Causes, the Plight and Preventive Actions
References
83. Stark O, Atkins E, Wolff OH, Douglas JW. Longitudinal study of obesity in the National Survey of
Health and Development. Br Med J (Clin Res Ed) 1981; 283(6283):13-7.
84. Guo SS, Chumlea WC.Tracking of body mass index in children in relation to overweight in adulthood.
Am J Clin Nutr 1999; 70(1):145S-8S.
85. Schmitz MK, Jeffery RW. Public health interventions for the prevention and treatment of obesity.
Med Clin North Am 2000; 84(2):491-512.
86. Jeffery RW, French SA, Raether C, Baxter JE. An environmental intervention to increase fruit and
salad purchases in a cafeteria. Prev Med 1994; 23(6):788-92.
87. Bush PJ, Zuckerman AE, Theiss PK, Taggart VS, Horowitz C, Sheridan MJ et al. Cardiovascular risk
factor prevention in black schoolchildren: two-year results of the “Know Your Body” program. Am J
Epidemiol 1989; 129(3):466-82.
88. Coates TJ, Jeffery RW, Slinkard LA. Heart healthy eating and exercise: introducing and maintaining
changes in health behaviors. Am J Public Health 1981; 71(1):15-23.
89. Sahota P, Rudolf MC, Dixey R, Hill AJ, Barth JH, Cade J. Randomised controlled trial of primary
school based intervention to reduce risk factors for obesity. BMJ 2001; 323(7320):1029-32.
90. Muller MJ, Asbeck I, Mast M, Langnase K, Grund A. Prevention of obesity—more than an intention.
Concept and first results of the Kiel Obesity Prevention Study (KOPS). Int J Obes Relat Metab Disord
2001; 25 Suppl 1:S66-74.
91. Simonetti DA, Tarsitani G, Cairella M, Siani V, De Filippis S, Mancinelli S et al. Prevention of obesity
in elementary and nursery school children. Public Health 1986; 100(3):166-73.
92. Harrell JS, McMurray RG, Bangdiwala SI, Frauman AC, Gansky SA, Bradley CB. Effects of a schoolbased intervention to reduce cardiovascular disease risk factors in elementary-school children: the
Cardiovascular Health in Children (CHIC) study. J Pediatr 1996; 128(6):797-805.
93. Holcomb JD, Lira J, Kingery PM, Smith DW, Lane D, Goodway J. Evaluation of Jump Into Action:
a program to reduce the risk of non-insulin dependent diabetes mellitus in school children on the
Texas-Mexico border. J Sch Health 1998; 68(7):282-8.
94. Alexandrov AA, Maslennikova GY, Kulikov SM, Propirnij GA, Perova NV. Primary prevention
of cardiovascular disease: 3-year intervention results in boys of 12 years of age. Prev Med 1992;
21(1):53-62.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
52
References
95. Petchers MK, Hirsch EZ, Bloch BA. A longitudinal study of the impact of a school heart health
curriculum. J Community Health 1988; 13(2):85-94.
96. Puska P,Vartiainen E, Pallonen U, Salonen JT, Poyhia P, Koskela K et al. The North Karelia youth
project: evaluation of two years of intervention on health behavior and CVD risk factors among 13to 15-year old children. Prev Med 1982; 11(5):550-70.
97. Killen JD, Robinson TN, Telch MJ, Saylor KE, Maron DJ, Rich T et al. The Stanford Adolescent
Heart Health Program. Health Educ Q 1989; 16(2):263-83.
98. Prevention of obesity in American Indian children: the Pathways study. Am J Clin Nutr 1999; 69(4
Suppl):745S-824S.
99. Homel PJ, Daniels P, Reid TR, Lawson JS. Results of an experimental school-based health
development programme in Australia. Int J Health Educ 1981; 24(4):263-70.
100. Neumark-Sztainer D, Story M, Hannan PJ, Rex J. New Moves: a school-based obesity prevention
program for adolescent girls. Prev Med 2003; 37(1):41-51.
101. Wadden TA, Brownell KD, Foster GD. Obesity: responding to the global epidemic. J Consult Clin
Psychol 2002; 70(3):510-25.
102. Health promoting school & school curriculum. Hong Kong: Education and Manpower Bureau;
2004.
103. Lee A, Tsang C, Tso C, Ho M, Ng P, Yue S et al. Healthy breakfast campaign: Guinness record. J
Primary Care & Health Promotion 2004; 1(1):10-6.
104. Centers for Diseases Control and Prevention. Preventing obesity among children. Chronic Disease
Notes & Reports 2000; 13(1):1-6.
105. Robinson TN.Television viewing and childhood obesity. Pediatr Clin North Am 2001; 48(4):1017-25.
106. Robinson TN. Reducing children’s television viewing to prevent obesity: a randomized controlled
trial. JAMA 1999; 282(16):1561-7.
107. Gortmaker SL, Peterson K, Wiecha J, Sobol AM, Dixit S, Fox MK et al. Reducing obesity via a
school-based interdisciplinary intervention among youth: Planet Health. Arch Pediatr Adolesc Med 1999;
153(4):409-18.
108. Kahn EB, Ramsey LT, Brownson RC, Heath GW, Howze EH, Powell KE et al. The effectiveness of
interventions to increase physical activity. A systematic review. Am J Prev Med 2002; 22(4 Suppl):73-107.
53
Tackling Obesity: Its Causes, the Plight and Preventive Actions
References
109. Dale D, Corbin CB. Physical activity participation of high school graduates following exposure to
conceptual or traditional physical education. Res Q Exerc Sport 2000; 71(1):61-8.
110. Sallis JF, McKenzie TL, Alcaraz JE, Kolody B, Hovell MF, Nader PR. Project SPARK. Effects of
physical education on adiposity in children. Ann N Y Acad Sci 1993; 699:127-36.
111. Mo-suwan L, Pongprapai S, Junjana C, Puetpaiboon A. Effects of a controlled trial of a school-based
exercise program on the obesity indexes of preschool children. Am J Clin Nutr 1998; 68(5):1006-11.
112. Ewart CK,Young DR, Hagberg JM. Effects of school-based aerobic exercise on blood pressure in
adolescent girls at risk for hypertension. Am J Public Health 1998; 88(6):949-51.
113. Flores R. Dance for health: improving fitness in African American and Hispanic adolescents. Public
Health Rep 1995; 110(2):189-93.
114. Duncan B, Boyce WT, Itami R, Puffenbarger N. A controlled trial of a physical fitness program for
fifth grade students. J Sch Health 1983; 53(8):467-71.
115. Sallis JF, McKenzie TL, Alcaraz JE, Kolody B, Hovell MF, Nader PR. Project SPARK. Effects of
physical education on adiposity in children. Ann N Y Acad Sci 1993; 699:127-36.
116. Lee PM. Exercise kid songs program: promote regular physical activities in pre-school children.
Health Promotion Workforce Capacity Building Project 2001-2002. Hong Kong: Department of Health;
2002.
117. Department of Health and Human Services. Nutrition and your health: dietary guidelines for Americans.
Fourth edition. Washington, DC: Department of Agriculture; 2000.
118. Krebs-Smith SM, Cook A, Subar AF, Cleveland L, Friday J, Kahle LL. Fruit and vegetable intakes
of children and adolescents in the United States. Arch Pediatr Adolesc Med 1996; 150(1):81-6.
119. Centers for Disease Control and Prevention. Nutrition and physical activity. 5 A day. 2004. Available
at http://www.cdc.gov/nccdphp/dnpa/5ADay/faq/size_1.htm. Accessed 15 March, 2005.
120. Perry CL, Bishop DB, Taylor G, Murray DM, Mays RW, Dudovitz BS et al. Changing fruit and
vegetable consumption among children: the 5-a-Day Power Plus program in St. Paul, Minnesota.
Am J Public Health 1998; 88(4):603-9.
121. Reynolds KD, Franklin FA, Binkley D, Raczynski JM, Harrington KF, Kirk KA et al. Increasing
the fruit and vegetable consumption of fourth-graders: results from the high 5 project. Prev Med
2000; 30(4):309-19.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
54
References
122. Manios Y, Moschandreas J, Hatzis C, Kafatos A. Evaluation of a health and nutrition education
program in primary school children of Crete over a three-year period. Prev Med 1999; 28(2):
149-59.
123. James J, Thomas P, Cavan D, Kerr D. Preventing childhood obesity by reducing consumption of
carbonated drinks: cluster randomised controlled trial. BMJ 2004; 328(7450):1237.
124. Department of Health. Report on the healthy tuckshop movement for primary schools 1999-2001. Hong
Kong: Department of Health; 2003.
125. Department of Health. Report on the healthy eating movement for kindergartens and nursery schools 19992001. Hong Kong: Department of Health; 2004.
126. Department of Health. Healthy birthday party. Hong Kong: KLW/KLC/KT District Health
Committee DoH; 2000.
127. Smith BJ, Merom D, Harris P, Bauman A. Do primary care interventions to promote physical activity
work? A systematic review of the literature. Sydney: NSW Centre for Physical Activity and Health;
2002.
128. Blair SN, Smith M, Collingwood TR, Reynolds R, Prentice MC, Sterling CL. Health promotion
for educators: impact on absenteeism. Prev Med 1986; 15(2):166-75.
129. Cardinal BJ, Sachs ML. Prospective analysis of stage-of-exercise movement following mail-delivered,
self-instructional exercise packets. Am J Health Promot 1995; 9(6):430-2.
130. Chen AH, Sallis JF, Castro CM, Lee RE, Hickmann SA, William C et al. A home-based behavioral
intervention to promote walking in sedentary ethnic minority women: project WALK. Womens
Health 1998; 4(1):19-39.
131. Dunn AL, Marcus BH, Kampert JB, Garcia ME, Kohl HW, III, Blair SN. Comparison of lifestyle
and structured interventions to increase physical activity and cardiorespiratory fitness: a randomized
trial. JAMA 1999; 281(4):327-34.
132. Coleman KJ, Raynor HR, Mueller DM, Cerny FJ, Dorn JM, Epstein LH. Providing sedentary
adults with choices for meeting their walking goals. Prev Med 1999; 28(5):510-9.
133. Patterson RE, Kristal AR, Biener L,Varnes J, Feng Z, Glanz K et al. Durability and diffusion of the
nutrition intervention in the Working Well Trial. Prev Med 1998; 27(5 Pt 1):668-73.
134. Heirich MA, Foote A, Erfurt JC, Konopka B. Work-site physical fitness programs. Comparing the
impact of different program designs on cardiovascular risks. J Occup Med 1993; 35(5):510-7.
55
Tackling Obesity: Its Causes, the Plight and Preventive Actions
References
135. King AC, Carl F, Birkel L, Haskell WL. Increasing exercise among blue-collar employees: the
tailoring of worksite programs to meet specific needs. Prev Med 1988; 17(3):357-65.
136. Bertera RL. Behavioral risk factor and illness day changes with workplace health promotion: twoyear results. Am J Health Promot 1993; 7(5):365-73.
137. Barratt A, Reznik R, Irwig L, Cuff A, Simpson JM, Oldenburg B et al. Work-site cholesterol
screening and dietary intervention: the Staff Healthy Heart Project. Steering Committee. Am J
Public Health 1994; 84(5):779-82.
138. Cook C, Simmons G, Swinburn B, Stewart J. Changing risk behaviours for non-communicable
disease in New Zealand working men-is workplace intervention effective? N Z Med J 2001; 114
(1130):175-8.
139. Gomel M, Oldenburg B, Simpson JM, Owen N. Work-site cardiovascular risk reduction: a
randomized trial of health risk assessment, education, counseling, and incentives. Am J Public Health
1993; 83(9):1231-8.
140. Sorensen G, Thompson B, Glanz K, Feng Z, Kinne S, DiClemente C et al. Work site-based cancer
prevention: primary results from the Working Well Trial. Am J Public Health 1996; 86(7):939-47.
141. King AC, Frederiksen LW. Low-cost strategies for increasing exercise behavior. Relapse preparation
training and social support. Behavior Modification 1984; 8(1):3-21.
142. Simmons D, Fleming C,Voyle J, Fou F, Feo S, Gatland B. A pilot urban church-based programme
to reduce risk factors for diabetes among Western Samoans in New Zealand. Diabet Med 1998;
15(2):136-42.
143. Lombard DN, Lombard TN,Winett RA.Walking to meet health guidelines: the effect of prompting
frequency and prompt structure. Health Psychol 1995; 14(2):164-70.
144. King AC, Taylor CB, Haskell WL, Debusk RF. Strategies for increasing early adherence to and
long-term maintenance of home-based exercise training in healthy middle-aged men and women.
Am J Cardiol 1988; 61(8):628-32.
145. Wankel LM, Yardley JK, Graham J. The effects of motivational interventions upon the exercise
adherence of high and low self-motivated adults. Can J Appl Sport Sci 1985; 10(3):147-56.
146. Bedell BA, Shackleton PA. The relationship between a nutrition education program and nutrition
knowledge and eating behaviors of the elderly. J Nutr Elder 1989; 8(3-4):35-45.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
56
References
147. Lalonde B, Hooyman N, Blumhagen J. Long-term outcome effectiveness of a health promotion
program for the elderly: The Wallingford Wellness Project. J Gerontological Social Work 1988; 13
(1/2):95-112.
148. Kriska AM, Bayles C, Cauley JA, LaPorte RE, Sandler RB, Pambianco G. A randomized exercise
trial in older women: increased activity over two years and the factors associated with compliance.
Med Sci Sports Exerc 1986; 18(5):557-62.
149. Jarvis KL, Friedman RH, Heeren T, Cullinane PM. Older women and physical activity: using the
telephone to walk. Womens Health Issues 1997; 7(1):24-9.
150. Andersen RE, Franckowiak SC, Snyder J, Bartlett SJ, Fontaine KR. Can inexpensive signs encourage
the use of stairs? Results from a community intervention. Ann Intern Med 1998; 129(5):363-9.
151. Blamey A, Mutrie N, Aitchison T. Health promotion by encouraged use of stairs. BMJ 1995; 311
(7000):289-90.
152. Brownell KD, Stunkard AJ, Albaum JM. Evaluation and modification of exercise patterns in the
natural environment. Am J Psychiatry 1980; 137(12):1540-5.
153. Kerr J, Eves F, Carroll D. Posters can prompt less active people to use the stairs. J Epidemiol Community
Health 2000; 54(12):942.
154. Russell WD, Dzewaltowski DA, Ryan GJ.The effectiveness of a point-of-decision prompt in deterring
sedentary behavior. Am J Health Promot 1999; 13(5):257-9, ii.
155. Department of Health. Guidebook on organizing stair climbing campaign. Hong Kong: Department of
Health; 2004.
156. Fortmann SP, Williams PT, Hulley SB, Haskell WL, Farquhar JW. Effect of health education on
dietary behavior: the Stanford Three Community Study. Am J Clin Nutr 1981; 34(10):2030-8.
157. Jeffery RW, Gray CW, French SA, Hellerstedt WL, Murray D, Luepker RV et al. Evaluation of
weight reduction in a community intervention for cardiovascular disease risk: changes in body mass
index in the Minnesota Heart Health Program. Int J Obes Relat Metab Disord 1995; 19(1):30-9.
158. Puska P, Tuomilehto J, Salonen J, Neittaanmaki L, Maki J,Virtamo J et al. Changes in coronary risk
factors during comprehensive five-year community programme to control cardiovascular diseases
(North Karelia project). BM J 1979; 2(6199):1173-8.
57
Tackling Obesity: Its Causes, the Plight and Preventive Actions
References
159. Tudor-Smith C, Nutbeam D, Moore L, Catford J. Effects of the Heartbeat Wales programme over
five years on behavioural risks for cardiovascular disease: quasi-experimental comparison of results
from Wales and a matched reference area. BMJ 1998; 316(7134):818-22.
160. Osler M, Jespersen NB. The effect of a community-based cardiovascular disease prevention project
in a Danish municipality. Dan Med Bull 1993; 40(4):485-9.
161. Goodman RM, Wheeler FC, Lee PR. Evaluation of the Heart To Heart Project: lessons from a
community-based chronic disease prevention project. Am J Health Promot 1995; 9(6):443-55.
162. Taylor CB, Fortmann SP, Flora J, Kayman S, Barrett DC, Jatulis D et al. Effect of long-term
community health education on body mass index. The Stanford Five-City Project. Am J Epidemiol
1991; 134(3):235-49.
163. Ho CL. To study the effects of a structured community-based intervention programme on physical
activity of adult women in a public housing estate in Hong Kong. Health Promotion Workforce Capacity
Building Project 2001-2002. Hong Kong: Department of Health; 2002.
164. 15 popular fast food. Choices 2003; 323:22-7.
165. Perlmutter CA, Canter DD, Gregoire MB. Profitability and acceptability of fat- and sodium-modified
hot entrees in a worksite cafeteria. J Am Diet Assoc 1997; 97(4):391-5.
166. French SA, Story M, Jeffery RW, Snyder P, Eisenberg M, Sidebottom A et al. Pricing strategy to
promote fruit and vegetable purchase in high school cafeterias. J Am Diet Assoc 1997; 97(9):1008-10.
167. French SA, Jeffery RW, Story M, Hannan P, Snyder MP. A pricing strategy to promote low-fat
snack choices through vending machines. Am J Public Health 1997; 87(5):849-51.
168. French SA, Jeffery RW, Story M, Breitlow KK, Baxter JS, Hannan P et al. Pricing and promotion
effects on low-fat vending snack purchases: the CHIPS Study. Am J Public Health 2001; 91(1):
112-7.
169. Ishibashi L, Woldow D, Grannan G. K-12 at a crossroads: one school’s uncanny success with junk-food
ban. San Francisco: Chronicle; 2003.
170. Urban & Environmental Policy Institute. Challenging the soda companies: The Los Angeles Unified
School District Soda Ban. Available at: http://departments.oxy.edu/uepi/cfj/resources/SodaBan.htm.
Accessed 15 March, 2005.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
58
References
171. Education and Manpower Bureau. Meal arrangements in schools. Hong Kong: Education and
Manpower Bureau. Available at http://www.emb.gov.hk/FileManager/EN/Content_2501/
guidelinemealarrangement_e.pdf. Accessed 15 March, 2005.
172. Horgen KB, Choate M, Brownell KD. Handbook of children and the media. Thousand Oak: Sage
Publications; 2001
173. Jacobson MF, Brownell KD. Small taxes on soft drinks and snack foods to promote health. Am J
Public Health 2000; 90(6):854-7.
174. Irwin T. Nutrition labelling-the DAA perspective. Nutr Diet 2002; 59:48-51.
175. Democratic Party. Nutrition labelling survey. Hong Kong: Democratic Party. Available at: http://
www.dphk.org/2003/images/thumbphoto/envir030315.doc. Accessed 15 March, 2005.
176. Consumer Council. Competition policy study. Submission from the Consumer Council to Legislative Council
Panel on food safety and environmental hygiene on nutrition labelling and the regulation of genetically modified
food. Hong Kong; 2003.
177. Health, Welfare and Food Bureau. Consultation paper on labelling scheme on nutrition information. Hong
Kong: Health, Welfare and Food Bureau; 2003.
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Tackling Obesity: Its Causes, the Plight and Preventive Actions
Appendices
Appendix 1
Weight-for-height reference chart for boys and girls.
Obesity defined as weight > median weight-for-height x 120%.
Wasting defined as weight < median weight-for-height x 80%.11
Weight for Height (Boys)
kg
100
90
%
97
80
90
70
75
60
50
25
Weight
10
50
3
40
30
20
10
0
55
65
75
85
95
105
115
125
Height
135
145
155
165
170
CM
Tackling Obesity: Its Causes, the Plight and Preventive Actions
60
Appendices
Weight for Height (Girls)
kg
80
%
97
70
90
60
75
50
50
25
10
3
Weight
40
30
20
10
0
55
65
75
85
95
105
115
Height
61
Tackling Obesity: Its Causes, the Plight and Preventive Actions
125
135
145
155
165
CM
Appendices
Appendix 2
International cut-off points for BMI for overweight and obesity by sex between 2 and 18 years
of age, defined to pass through BMI of 25 and 30 kg/m2 at age 18, obtained by averaging data
from Brazil, Hong Kong, the Netherlands, Singapore, the UK and the US.13
Age (years)
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
7
7.5
8
8.5
9
9.5
10
10.5
11
11.5
12
12.5
13
13.5
14
14.5
15
15.5
16
16.5
17
17.5
18
BMI 25 kg/m2
Male
Female
18.4
18.0
18.1
17.8
17.9
17.6
17.7
17.4
17.6
17.3
17.5
17.2
17.4
17.1
17.5
17.2
17.6
17.3
17.7
17.5
17.9
17.8
18.2
18.0
18.4
18.3
18.8
18.7
19.1
19.1
19.5
19.5
19.8
19.9
20.2
20.3
20.6
20.7
20.9
21.2
21.2
21.7
21.6
22.1
21.9
22.6
22.3
23.0
22.6
23.3
23.0
23.7
23.3
23.9
23.6
24.2
23.9
24.4
24.2
24.5
24.5
24.7
24.7
24.8
25
25
BMI 30 kg/m2
Male
Female
20.1
20.1
19.8
19.5
19.6
19.4
19.4
19.2
19.3
19.1
19.3
19.1
19.3
19.2
19.5
19.3
19.8
19.7
20.2
20.1
20.6
20.5
21.1
21.0
21.6
21.6
22.2
22.2
22.8
22.8
23.4
23.5
24.0
24.1
24.6
24.8
25.1
25.4
25.6
26.1
26.0
26.7
26.4
27.2
26.8
27.8
27.2
28.2
27.6
28.6
28.0
28.9
28.3
29.1
28.6
29.3
28.9
29.4
29.1
29.6
29.4
29.7
29.7
29.8
30
30
Tackling Obesity: Its Causes, the Plight and Preventive Actions
62
Appendices
Appendix 3
Summary of evidence on preventing obesity interventions
Stage
Intervention
Evidence
Infancy
Breastfeeding
Breastfeeding has been shown to have protective
effect against obesity as well as other benefits
to mothers and infants. The continued
protection, promotion and support of
breastfeeding remain a major health priority.
Childhood/
Adolescence
School-based programmes to
reduce sedentary activities
Some initiatives to reduce sedentary activities
resulted in decreases in reported TV-watching
time.
School-based programmes on
physical education
There was strong evidence in increasing
physical activity levels and improving physical
fitness among students.
School-based programmes on
dietary modification
Initiatives increased health knowledge and
consumption of fruit and vegetables by the
students.
Promoting physical activity in
primary care settings
As a sole initiative, it was not sufficient enough
to increase physical activity levels. It needs to
be incorporated within multi-faceted,
community-wide strategies.
Tailor-made physical activity with
behavioural components
Initiatives proved generally effective in
increasing physical activity levels. A decrease
in body weight or percentage of body fat has
been reported in some studies.
Workplace initiatives on physical
activity and/or dietary
modification
Initiatives were effective in getting people
to exercise more.
Promoting physical activity using
social support initiatives
Most were effective in getting people to be
more physically active.
Commercial services and products
for weight control
There is a lack of scientific evidence for the
effectiveness in losing weight or decreasing BMI.
Adulthood
63
Tackling Obesity: Its Causes, the Plight and Preventive Actions
Appendices
Old Age
General
Environment
and Policy
Nutritional education classes
Effect of nutrition programmes on older people
is still controversial.
Physical activity groups
They were effective in increasing the physical
activity levels among the elderly.
Point-of-decision prompts to
promote physical activity
They were effective in increasing levels of
physical activity.
Community-wide campaigns to
reduce risk factors of
non-communicable diseases
Campaigns were successful in increasing the
levels of physical activity and changing the
diet towards healthier eating.
Reducing price or increasing the Increasing the availability of healthy foods was
availability of healthy food choices associated with an increase in healthy food sales.
in vending machines or cafeterias
Restricting sale of soft drinks and
unhealthy snacks in school tuckshops
Further research will be needed to evaluate the
effects of this initiative.
Regulating food advertisements
for children
Further research will be needed to evaluate the
effects of this initiative.
Tax on unhealthy foods
Further research will be needed to evaluate the
effects of this initiative.
Nutrition labelling
Further research will be needed to evaluate the
effects of this initiative.
Working with the food industry
Further research will be needed to evaluate the
effects of this initiative.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
64
Resources Link
Central Health Education Unit,
Department of Health, HKSAR
http://www.cheu.gov.hk/eng/resources/exercise2_boards.htm
Childhood Obesity,
NSW Health
http://www.health.nsw.gov.au/obesity/
Food and Nutrition Information Center,
National Agricultural Library/USDA
http://www.nal.usda.gov/
International Association for the Study of Obesity
http://www.iaso.org/
International Obesity Task Force
http://www.iotf.org/
Resource Guide for Nutrition and Physical Activity Interventions to Prevent Obesity and Other Chronic Diseases,
National Centre for Chronic Disease Prevention and Health Promotion
http://www.cdc.gov/nccdphp/dnpa/obesityprevention.htm
World Health Organization (WHO)
http://www.who.int/health_topics/obesity/en/
The Surgeon General’s call to action to prevent and decrease overweight and obesity,
The Surgeon General
http://www.surgeongeneral.gov/topics/obesity/
68
65
Tackling Obesity: Its Causes, the Plight and Preventive Actions
Glossary
Adiposity: The state of being fat.
Cardiovascular diseases (CVD): Any abnormal condition characterised by dysfunction of the heart and
blood vessels.
Cerebrovascular disease: Damage to blood vessels in the brain.Vessels can burst and bleed or become clogged
with fatty deposits.When blood flow is interrupted, brain cells die or are damaged, resulting in a stroke.
Cholesterol: A lipid unique to animal cells that is used in the construction of cell membranes and as a
building block for some hormones.
Coronary heart disease: A condition in which the coronary arteries narrow from an accumulation of
plaque (atherosclerosis) and cause a decrease in blood flow.
Cross-sectional study: In a cross-sectional study, a defined population is observed for the presence or
absence of an outcome of interest and possible risk factors at a single point in time or time interval.
Diabetes mellitus: A disorder that prevents the body from converting digested food into the energy needed
for daily activities due to a deficiency of insulin. It is characterised by excess sugar in the blood and urine.
Fasting glucose test: A method for learning how much glucose (sugar) there is in a blood sample taken
after an overnight fast. The fasting blood glucose test is commonly used in the detection of diabetes
mellitus.
Gallbladder: A small pear-shaped organ situated directly under the liver in the right upper quadrant of
the abdomen. Its main function is to collect and concentrate the bile that the body uses to digest fats.
Gout: Condition characterised by abnormally elevated levels of uric acid in the blood, recurring attacks of
joint inflammation (arthritis), deposits of hard lumps of uric acid in and around the joints, and decreased
kidney function and kidney stones.
Hypertension: A common disorder in which blood pressure remains abnormally high.
Infertility: The state of being unable to produce offspring .
Initiative: Specific services, activities or products developed and implemented to change or improve
programme participants’ knowledge, attitudes, behaviour or awareness.
Insulin: A hormone in the body that helps move glucose (sugar) from the blood to muscles and other
tissues. Insulin controls blood sugar levels.
Lipid: A fatty substance in the blood.
Metabolism: Metabolism is the sum of all the chemical and physical changes that take place within the
body to enable its continued growth and functioning.
Tackling Obesity: Its Causes, the Plight and Preventive Actions
66
Glossary
Mortality: A measure of the frequency of occurrence of death in a defined population during a specified
interval of time.
Musculoskeletal system: The soft tissue and bones in the body. The parts of the musculoskeletal system
are bones, muscles, tendons, ligaments, cartilage, nerves and blood vessels.
Osteoarthritis: A joint disease that is characterised by a breakdown of the cartilage and a deterioration of
the fluid in a joint. Symptoms of osteoarthritis include pain and stiffness.
Postpartum: The period immediately after a woman gives birth.
Prevalence: The number or proportion of cases or events or conditions in a given population.
Prochaska’s Stages of Changes Model: It is a model of intentional changes which focuses on the
decision making of the individual. Six stages of change are included in this model, namely precontemplation,
contemplation, preparation or determination, action, maintenance, and termination.
Prospective study: A study in which participants are initially enrolled, examined or tested for risk factors,
and then followed up at subsequent time(s) to determine their status with respect to the disease or condition
of interest.
Randomised controlled trial: Experiments in which individuals are randomly assigned into groups
called study and control groups. The study group receives the initiative while the control group does not
receive the initiative.
Stroke: The sudden disruption of blood flow to the brain.
Systematic review: A review of studies in which evidence has been systematically searched for, studied,
assessed, and summarised according to predetermined criteria. It often uses meta-analysis to summarise
results of comparable studies.
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Tackling Obesity: Its Causes, the Plight and Preventive Actions