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Public Health Epidemiology in Ontario and Statistics Canada – Opportunities / Challenges / Questions. Michael Wolfson Statistics Canada October 15, 2007. Statistics Canada Provides:. a wide variety of data geographic data infrastructure various summary indicators

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public health epidemiology in ontario and statistics canada opportunities challenges questions

Public Health Epidemiology in Ontario and Statistics Canada – Opportunities / Challenges / Questions

Michael Wolfson

Statistics Canada

October 15, 2007

statistics canada provides
Statistics Canada Provides:
  • a wide variety of data
  • geographic data infrastructure
  • various summary indicators
  • analytical studies and reports
  • record linkage capacity
  • simulation modeling tools
ont web site
(ont web site)


ontario government tools
Ontario Government Tools
  • “The Health Analysts Toolkit”
  • “Ontario Health Planning Survey Guide”
  • “Ontario Health Planning Data Guide”
  • produced by Health Systems Intelligence Project of the Ontario MOHLTC – Jan 2006
  • provides an excellent review of many data sets, including those from Statistics Canada
  • cross-sectional survey (CCHS etc.)
    • provides a “snapshot” of a population at a certain point in time
  • longitudinal survey (NPHS)
    • surveys the same group of people repeatedly over time
    • provides dynamic information on the “trajectories” followed by a population
    • Permits examination of cause-effect relationships
cchs 1 s objectives
CCHS “.1’s” – Objectives
  • Support pan-Canadian health surveillance
    • nationally-comparable population health data for provinces and health regions
  • Support health research on small populations and rare characteristics 
  • Make information readily available to a diversified user community in a timely fashion
  • Offer a flexible survey instrument, including a rapid response option for emerging issues
cchs 1 design
CCHS “.1” Design
  • large sample: originally ~ 130,000 respondents per year, every other year
    • Stratified to produce estimates for sub-provincial health regions, provinces, territories & Canada
    • Residents of private households aged 12+
  • mix of personal and telephone interviews
    • Interview of 40-45 minutes
  • broad range of content
cchs 1 s content
CCHS “.1’s” – Content
  • household basics – demography, SES
  • common content (30 minutes)
    • asked of all respondents
    • Core content (20 minutes) included in questionnaire every year
    • Theme content (10 minutes) rotates according to consensus-based long-term plan
  • optional content (10 minutes)
cchs 1 survey redesign
CCHS “.1” - Survey Redesign
  • Continuous collection
    • started in Jan. 2007
    • ~65,000 respondents per year, every year
    • non-overlapping 2-month collection periods
  • Questionnaire / Content
    • Common content split into theme and core content
    • Long-term plan for theme content
    • Maintain optional content
    • Capacity to include a maximum of 2 min. of extra content “on the fly” (Rapid Response)
  • Data will be available more often
    • Annual data release
cchs 1 theme content long term plan
CCHS “.1” Theme Content Long-term plan

Rapid Response - $ (max of 2 minutes)

cchs 2 objectives
CCHS “.2” – Objectives
  • (originally in intervening years)
  • support in-depth research on specific topics or themes
    • cycle 1.2 (2002) → Mental Health and Well-being
    • cycle 2.2 (2004) → Nutrition
    • (cycle 3.2 → CHMS)
    • cycle 4.2 (2008) → Healthy Aging
  • provincial level (only) detail
cchs cycle 1 2 2002 mental health well being objectives
CCHS Cycle 1.2 (2002) Mental Health & Well-being – Objectives
  • estimate prevalence in the general population of selected mental health disorders
  • provide information on the utilization of mental health services and perceived health needs
  • provide data on the disability / impact associated with mental health problems to both individuals and society
  • examine links between mental health and social, demographic, geographic and economic characteristics
cchs cycle 1 2 2002 design
CCHS Cycle 1.2 (2002) – Design
  • Target population:
    • persons aged 15+ living in private dwellings in the ten provinces (excludes territories)
  • Sample size ~37,000 respondents
  • Personal interview
    • limited (14%) telephone follow-up
    • telephone, non-proxy only
  • Five mental health disorders assessed
    • major depression, mania disorder, panic disorder, social phobia and agoraphobia
    • as well as alcohol and illicit drug dependence
  • Supplement on Canadian Forces
    • also assessed GAD and PTSD
    • active members and reserves
cchs 1 2 mental health well being
Alcohol use & dependence

Chronic Conditions


Eating troubles


General health

Height & weight

Illicit drug use & dependence

Medication use

Physical activities

Psychological well-being

Restriction of activities


Social support



Two-week disability

Work stress

Screening (diagnostic modules)



Panic disorder

Social phobia




Labour force


CCHS 1.2 - Mental Health & Well Being
Results from the CCHS Cycle 1.2 (2002) - Measured Mental Disorders or Substance Dependence / Past 12 Months
cchs cycle 2 2 2004 nutrition objectives
CCHS Cycle 2.2 (2004) Nutrition – Objectives
  • estimate the distribution of usual dietary intake
    • in terms of food groups, dietary supplements, nutrients and eating patterns through a dietary recall computer application
    • for a representative sample of Canadians at provincial and national levels
  • measure the prevalence of household food insecurity among various population groups in Canada
  • gather anthropometric measurements
    • body height and weight
  • collect correlate information
    • physical activity
    • selected health conditions
    • socio-demographic characteristics
cchs cycle 2 2 2004 nutrition design
CCHS Cycle 2.2 (2004) Nutrition – Design
  • Target population
    • persons of all ages living in private dwellings in the ten provinces (excluding the territories)
  • Sample size ~35,000
  • 1/3 of respondents asked second dietary recall to provide information on usual intake
    • personal interview for the 1st interview
    • telephone interview for the 2nd recall interview
  • Stratified by 10 provinces and 15 age-sex groups corresponding to Dietary Reference Intake groupings
cchs cycle 2 2 2004 nutrition content
Food consumption

24-hour dietary recall

USDA Automated Multiple Pass Methodology

Modified for Canadian marketplace

All foods and beverages

5 steps - improve chances of recalling all foods eaten

Quick List

Forgotten Foods

Time and Occasion

Detail Cycle

Final Probe

2nd interview

10,000 of 35,000 respondents

24-hour recall only

Other topics

Alcohol Consumption (age 12+)

Children’s Physical Activity (age 6 to 11)

Chronic Conditions (all)

Fruit and Vegetable Consumption (age 6 mo.+)

General Health (age 12+)

Household Food Security (all)

Measured Height and Weight (age 2+)

Physical Activity (age 12+)

Sedentary Activity (age 12 – 17)

Self Reported Height and Weight (10% sample, age 18+)

Smoking (age 12+)

Vitamin and Mineral Supplements (all)

Women’s Health (women age 9+)

Socio-Demographics (all)

Labour Force (age 15 – 75)

Income (all)

CCHS Cycle 2.2 (2004) Nutrition – Content

Results from CCHS Cycle 2.2 (2004) % above upper end of recommended range of total calories from fat, by age group and sex, population aged 4+, Canada excluding territories

2. Significantly different from estimate for previous age group of same sex (p < 0.05) Notes : Estimates of energy intake include calories from alcoholic beverages. Based on usual consumption. Excludes women who were pregnant or breastfeeding. E = use with caution / F = too unreliable to be published

Data source : 2004 Canadian Community Health Survey: Nutrition

Results from CCHS Cycle 2.2 (2004) distribution of BMI, population aged 12 to 17, Canada excluding territories, 1978/79 and 2004
cchs cycle 4 2 healthy aging
CCHS Cycle 4.2 Healthy Aging


  • factors, influences and processes that contribute to healthy aging
  • health, social and economic determinants


  • respondents aged 55+
  • sample size – to be determined
  • collection July 2008 to May 2009
  • computer Assisted Personal Interview (CAPI)
  • possible link to CLSA / longitudinal survey
health services access survey hsas
Health Services Access Survey (HSAS)
  • Fill gap in “Quality of service” indicator area
    • Access to 24/7 first contact health services
    • Waiting times for key diagnostic and treatment services
  • HSAS 2001
    • Collected as follow-up supplement to CCHS (.1)
    • 14,210 respondents
    • representative national-level estimates
    • sample buy-ins (P.E.I., Alta., B.C.)
  • HSAS 2003 & 2005
    • Integrated in CCHS (.1): sub-sample of 32,000+ respondents
    • representative provincial-level estimates
  • HSAS 2007
    • CCHS (.1) 2007 annual theme
    • Asked of a sub-sample of 32,000+ respondents
  • Future uncertain….
joint canada united states survey of health jcush objectives
Joint Canada / United States Survey of Health (JCUSH) - Objectives


  • Examine Canada-US differences in health status and use of health care services
  • Identify possible areas for collaboration in questionnaire design / development


  • Conducted jointly by Statistics Canada (STC) and the National Center for Health Statistics (NCHS)
  • Target population 18+ in private dwellings
  • Collection: fall 2002 to spring 2003
  • All interviews by telephone, conducted from STC regional offices
  • Sample size ~3,500 Canada / ~5,200 US
  • Standard approach across both countries
canadian health measures survey chms background
Canadian Health Measures Survey (CHMS) – Background
  • high-priority topics – e.g. environmental toxins, metabolic syndrome, physical fitness, other CHD risk factors – can only be assessed through direct physical measures
  • other high priority health information collected through self-report surveys or administrative records is subject to reporting error – e.g. obesity, hypertension
  • directly measured attributes can be measured more precisely / reported on continuous scales
chms objectives
CHMS – Objectives
  • estimate the numbers of individuals in Canada with selected health conditions, characteristics, and elevated levels of major risk factors
  • estimate the distributional patterns of selected diseases, risk factors and protective characteristics
  • monitor trends, based to the extent possible on available historical data
  • ascertain relationships among risk factors, protective behaviours, and health status
  • explore emerging public health issues and new measurement technologies
  • assess the validity of prevalence estimates based on self- and proxy-reported information
  • collect a nationally representative sample of genetic material and other covariates for future genetic research
  • provide a potential platform and infrastructure for ongoing physical measures surveys and add-on studies
  • share our experience with others
chms parameters
CHMS – Parameters
  • combination of household interview + direct measures completed in mobile exam clinic
  • national estimates, n = 5,000 over 2 years
  • atypical sample design – 15 clusters selected from 97% of population (due to cost, logistics)
  • Ages 6-79 (6-11, 12-19, 20-39, 40-59, 60-79)
  • 2007-2009 in the field
national population health survey nphs objectives
National Population Health Survey (NPHS) – Objectives
  • Support research into the dynamic processes of health
    • Provide data for analytical studies that will assist in understanding the determinants of health
  • Evaluate the relationships between socio-economic and demographic characteristics of individuals with their health status and its evolution over time
  • Aid in the development of public health policy
nphs household component
NPHS – Household Component
  • Main component of NPHS
    • persons in private households in the ten provinces
    • first cycle in 1994-95 → every two years
  • Cross-sectional sample
    • served cross-sectional purposes: 1994, 1996, 1998
      • subset of questionnaire – all members of household
      • detailed health information – selected household respondent
  • Longitudinal sample
    • same selected household respondent revisited each cycle
    • 17,276 respondents initially
    • detailed health information from selected respondent
    • socio-demographic information on household each cycle
      • including household composition, income, education
nphs other components
NPHS – Other Components
  • Intended to complement main NPHS household component
  • Institutions component
    • Residents of long-term care institutions (4+ beds) in the ten provinces
    • 5 cycles of data: 1994-95 → every two years to 2002-03
    • Sample ~2,200 respondents → national level data
    • High mortality: ~1/3 of respondents each cycle
  • North component
    • Household residents in each territory
    • 3 cycles of data, 1994-95 → every two years to 1998-99
    • Sample ~2,000 respondents → territorial level data
    • Territories covered by the CCHS “.1’s” since 2000
cross sectional vs longitudinal findings shift work and the health of males

Cross-sectional vs longitudinal findingsShift work and the health of males


Longitudinal results: Working shift was associated with increased health risks over time. Working a non-standard schedule in 94/95 was predictive of developing chronic diseases over the next 4 years.

Cross-sectional results: The odds of having been diagnosed with a chronic disease did not differ for men who worked shift compared with those working a regular daytime schedule

N. B. bars represent 95% confidence intervals;

colour change occurs at mean relative risk

Source: NPHS

some other survey data sets
Some Other Survey Data Sets
  • population census – disability screener
  • major surveys
    • HALS / PALS – Health / Participation and Activity Limitations Surveys (post-censal)
    • NLSCY – National Longitudinal survey of Children and Youth
  • related surveys
    • SHS/FAMEX – Survey of Household Spending, formerly FAMily EXpenditure survey
    • GSS – General Social Survey
cancer registration in canada
Cancer Registration In Canada
  • Originated at varying times across country

Provincial level 1st : 1935 BC & Sask

  • NCIRS: 1969 - 1991 at Statistics Canada
  • 1992 : CCR established – new standards
canadian cancer registry ccr
CanadianCancer Registry (CCR)

Key Features

  • Reference Year - 1992
  • Person Oriented Data Set

- Person & Tumor Records

- Data Definitions/Standards

  • National Coverage
  • Internal Duplicate Protocol
  • CMDB Linkage & Clearance
ccr how it is used
CCR: How it is used
  • Calculate cancer incidence and survival statistics
  • Occupational, environmental and other medical follow-up studies
  • Production of the Canadian Cancer Statistics monograph
  • Research programs i.e. tobacco control, product safety, workplace health and safe environments
  • Assess the impact of new technologies and treatments
an almost familiar world map
An Almost Familiar World Map; cartogram algorithm: Mark Newman

health indicators
Health Indicators
  • joint Statistics Canada / CIHI set
    • equity dimension – needs development
  • Performance Indicators pursuant to First Ministers’ Health Accords
    • FPT process – moribund
  • note Ontario Indicators
  • QUESTION: what others?
data access
Data Access
  • print publications
  • web site – tables, studies, maps
  • microdata files (sometimes)
    • public use
    • via remote job submission
    • via the Research Data Centres
    • via the Ontario MOHLTC
  • QUESTION: what modes of access would be most useful
  • small area estimates
  • hypothesis testing
  • choice of content areas
  • measuring health status and health outcomes
  • comparability – beyond Canada?
  • beyond monitoring? (to causality / modeling)
definition health outcome

health status “before”

health status “after”

health intervention

other factors

Definition - Health Outcome

change in health status attributable to a health intervention (for an individual)

changes in life expectancy le and health adjusted life expectancy hale by cause canada
Changes in Life Expectancy (LE) and Health-Adjusted Life Expectancy (HALE) by Cause, Canada



(Source: Manuel et al, ICES and Health Canada, NPHS)

example of nphs analysis using lifepaths pohem
Example of NPHS Analysis Using LifePaths / POHEM
  • LifePaths and POHEM ( = Statistics Canada’s POpulation HEalth Model) – microsimulation-based projection tools
  • projecting disability prevalence
    • in the context of population aging, and
    • declining fertility rates,
    • rising divorce rates,
    • and recent trends in the levels of disability
    •  who will look after future frail elderly
disability definitions motivation
Disability Definitions – Motivation
  • define disability severity levels in terms of likely predictors of need for services
  • focus on activities commonly associated with use of home care services, e.g. everyday housework, grocery shopping, meal preparation, and personal care
  • use projections of these disability levels as rough proxy for inferred “population at risk” for service needs such as home care – if not from close relatives, then either purchased or from government
disability definitions specifics based on mcmaster hui3 most severe level
Disability Definitions – Specifics(based on McMaster HUI3, most severe level)
  • No disability
  • Mild disability
    • Mobility problem but do not need any help
    • Dexterity problem but do not need any help from someone else (may or may not use special equipment)
    • Somewhat forgetful and little difficulty in thinking
    • Moderate and/or severe pain prevents performing some or few activities
  • Moderate disability
    • Requires wheel chair or mechanical support to walk
    • Dexterity problem and need help to perform some tasks
    • Very forgetful and a lot of difficulty in thinking
    • Severe pain prevents performing most activities
  • Severe disability
    • Can not walk or need help from others to walk
    • Dexterity problem and need help for most or all tasks
    • Unable to remember or think
estimation of disability dynamics
Estimation of Disability Dynamics
  • data source: 1994, 1996, 1998 and 2000 waves of longitudinal NPHS (n = 287 to 12,733)
  • look at pairs of “triples” for dynamics – two overlapping sets of 3 waves for each individual
    • 1994 – 1996 – 1998, and 1996 – 1998 - 2000
    • recognizes a degree of duration dependence (i.e. nests and tests naïve first order Markov assumption)
    • allows assessment of unobserved person-specific factors
  • look at improvements or deteriorations only
    • not a limiting assumption given modeling in continuous time
  • use cross-validation to assess choice of specification (opportunistic, given bootstrap weights)
disability transition hazard regressions functional forms
Disability Transition Hazard Regressions – Functional Forms
  • age (cubic spline), prior disability
  • + (A) simple individual level variance
  • + (B) individual level variance covariates (education, nuptiality, immigration)
  • + (C) other covariates (year, sex, education, nuptiality, immigration)
  • results:
    • prior disability matters (i.e. 2nd order Markov)
    • (A) and (B) matter; (C) not
  • how to assess: use replicated “out of sample predictions” based on 500 bootstrap weight vectors
sub sample of 100 simulated life paths
Sub-Sample of 100 SimulatedLife Paths

vertical axis = 1.0 x years without disability + 0.8 x years with mild + 0.6 x moderate + 0.4 x severe + 0.2 x institutionalized

95life paths

4life paths

horizontal axis = 1.0 x years of age

projected canadian disability prevalences from 2001 to 2021
Projected Canadian Disability Prevalences from 2001 to 2021
  • darker blue = more severe disability, and ultimately institutionalization
  • triangles indicate (roughly) total 65+ population, and “healthy” 65+
concluding comments
Concluding Comments
  • Statistics Canada has a great deal of data
  • Ontario appears to be using much of it well
  • There are important areas of new development
    • evolution of CCHS
    • new CHMS
    • linkage of major surveys to provincial health care records
  • There are also questions
    • accessibility of data
    • priority content needs
    • potential of new tools – e.g. mapping, simulation models