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Canadian Public Health Association Conference
2008 Annual Conference
Public Health in Canada: Reducing Health Inequalities
through Evidence and Action
Halifax, Nova Scotia
June 1-4, 2008
The Prevalence of Depressive
Symptoms in Canadians at Midlife
Conita Ip, M.A. PhD Student
Jian Kang, PhD Candidate
University of Calgary
Introduction
• Depression is a common health problem
affecting 121 million people worldwide.
• By 2020, it is projected that depression would
become the second leading cause of global
disability and premature death (WHO, 2002).
Prevalence of Major Depressive Episode
in Canada
• 1 in 7 adults (13.4%) identified symptoms that met the
criteria for a mood disorder at some point during their
lifetime.
• The lifetime prevalence for depression in adults aged 15
and over was 12.2% while the 12-month prevalence was
4.8% (men: 3.7%, women: 5.9%).
(The human face of mental health and mental illness in Canada
2006 using data from the 2002 Mental Health and Well-being Survey
(CCHS 1.2))
Suicide Rates in Canada
• Statistics Canada reported that suicide is one of the
leading causes of death for both sexes from
adolescence to middle age.
• In 2003, 3,765 Canadians died due to suicide. Among
them, 1,337 were midlife adults aged 45-64, constituting
35.5% of all suicidal deaths.
(Centre for Chronic Disease Prevention and Control, Public Health
Agency of Canada using data from the Mortality File, Statistics
Canada)
Rationale for the Current Study
• Midlife is a crisis stage during which people begin to detach from
well-ordered life and experience changes in unanticipated ways
(Levinson, 1978; Vaillant, 1977) or an opportunity for growth ?
• It is a period the middle-aged adults negotiate with a wide range of
challenges in family, work and individual domains (Bumpass &
Aquilino, 1995).
• Despite the challenges facing midlife adults, the rising mid-aged
suicides and the fact that they constitute the largest subpopulation in
the country, research effort focusing on midlife psychological
wellbeing in Canada is limited.
• As such, an examination of the factors associated with midlife
depression is warranted.
Recent Research on
Midlife & Psychological Well-being
• Personality traits (low instrumentality, anger-in,
pessimism and anxiety traits) and life course
perspective/life events (becoming widowed, becoming a
caregiver, having undergone surgical menopause,
stressful life events and poor health status, having HIV
infection or AIDS, having personal perception of risk of
pandemic infection) are among the mainstream
explanations (Bromberger & Matthews, 1996a; 1996b;
Dennerstein et al., 2004; Kalichman et al, 2000; Klohnen,
Vandewater & Young, 1996; Turner, Killian & Cain, 2004; Woods,
Mitchell, 1997; Yu et al., 2005)
Limitations of Recent Research Studies
• Do not address the complex interplay of the individual
differences and their relationship with the socio-structural
environment.
• Almost all of the studies focused on middle-aged women
instead of looking at both sexes, thus cannot extend its
generalizability to the entire population.
• Sample bias – sample from higher socio-economic group
or lack of ethnic diversity
Theoretical Framework for the Current Study
• Individual factors and aspects of one’s social environment are key
elements related to health status (Keller-Olaman et al, 2004)
• Population health perspective has become significant in academic
and health policy discourse (Hayes & Dunn, 1998).
• It refers to the health of a population as measured by health status
indicators and as influenced by factors, including income and social
status, social support network, education and literacy, employment
and working condition, social environments, physical environments,
personal health practices and coping skills, healthy child
development, biology and genetic endowment, gender and culture
(Hayes and Dunn, 1998; Health Canada, 2002; Marmot & Wilkinson,
1999).
• There is a growing body of evidence that social environments are
crucially important for a healthy population. However, a systematic
review of the social determinants of mental health in middle-aged
Canadians is lacking.
Methods
• Canadian Community Health Survey (CCHS Cycle 2.1)
is a cross-sectional survey that collects information on
health status, health determinants and health care
utilization for the Canadian population aged 12 or older,
living in private dwellings.
• Data was collected between January 2003 and
December 2003, for 126 health regions, covering all
provinces and territories.
• In this study, we undertook an analysis of the cohort of
42,006 midlife subjects aged 40 to 59.
• After deletion of cases with missing values, the total
sample for analysis was reduced to 13,565.
• 12-month prevalence was estimated using logistic
regression analysis.
Measurement
• Composite International Diagnostic Interview-Short Form
(CIDI-SF) is a comprehensive, fully-standardised
diagnostic instrument designed tp provide a 12-month
prevalence estimates of depressive episodes in general
population based on the definitions and criteria of ICD-10
(International Classification of Diseases, version 10) and
DSM-III-R (Diagnostic and Statistical Manual of Mental
Disorders, 3rd ed., revised)
Variables
• Dependent/Outcome Variable: depression
• Independent Variables:
Gender
Age
Marital Status
Education
Income
Immigrant Status
Chronic Health Conditions
Results (1)
MDD Prevalence in relation to Demographic Variables
Variable
Category
Annual Prevalence(%)
Sex
Male
Female
7.5
12.3
Age
40-49
50-59
(Male)
8.8
6
(Female)
13.1
11.6
Marital Status
Married
Separated/Divorced/
Widowed
Single
5.9
12.9
9.6
17.5
9
16.5
Born in Canada
Immigrant
8
4.9
12.9
9.5
Ethnicity
Results (2)
MDD Prevalence in relation to Demographic Variables
Variable
Category
Annual Prevalence(%)
(Male) (Female)
Education
Less than Secondary
Secondary or above
8.6
7.3
13.6
12.1
Annual Income
Less than $15,000
$15,000-29,000
$30,000-49,000
$50,000 or above
13.7
8.2
7.3
6.1
14.3
11.7
12.6
9.4
Chronic Illness
Has a chronic condition
No chronic condition
3.2
9.3
3.9
14.4
Discussions
• Consistent with previous research, those who are
women, with less education, less income, chronic illness,
and being widowed, separated, divorced and single have
higher prevalence of depressive symptoms.
• Immigrants experience lower prevalence of depressive
episodes probably because the pre-entry process has
screened out individuals with health problems, as well
the cultural differences in expression of emotions.
Recommendations
• Structural Level –
-Creating supportive environment
-Reorienting health care delivery models (e.g. customeroriented, training of GPs in identification of negative emotions)
-Reorienting public policy
• Individual Level –
-Enhancing personal capacity on recovery and
reintegration into community.
Limitations
• CCHS 2.1 is a cross-sectional survey, does not reflect
the causal relationship between variables.
• CIDI-SF is a non-clinical diagnostic instrument used by
trained lay interviewers, lacks clinical judgement.
• Lots of missing data in the variables of work stress and
social support which are two crucial areas for explaining
the prevalence of depression.
Thank You