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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. Copies of this publication are available from the Central Health Education Unit and from the website http://www.cheu.gov.hk. Printed by the Government Logistics Department (Printed with environmentally friendly ink on paper made from woodpulp derived from sustainable forests) 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 vi 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. 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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. 67 Tackling Obesity: Its Causes, the Plight and Preventive Actions