Physical activity of baby boomers compared to older and younger generations in Canada:

1. Physical activity of baby boomers compared to older and younger generations in Canada: An age-period-cohort analysis MayileeCanizares, Elizabeth Badley, Monique Gignac, Sheilah Hogg-Johnson, and Anthony Perruccio University Health Network, Toronto, Canada, University of Toronto, Toronto, Canada, Institute for Work and Health, Toronto, Canada Canadian Public Health Association May 2014

2. Background • Physical activity has well-documented health benefits. • Studies using repeated cross-sectional surveys indicate that participation in leisure time physical activities (LTPA) has increased over time. • Also being sedentary in usual activities has increased over time. • Cross-sectional studies suggest that participation in LTPA decline with age and is also lower in younger birth cohorts. • It is not well documented if these changes in LTPA over time differ by birth cohorts.

3. Objectives • To examine birth cohort and/or period effects (secular changes) in the age-trajectories of LTPA over 16 years among Canadian adults. • To examine whether the age-trajectories of LTPA were associated with changes in usual activities after controlling for sex, educational attainment, income, and BMI.

4. What are age, period, and cohort effects? • Age effects are the consequences of growing older. • How things change with age irrespective of birth cohort and calendar time • Period effects are the consequences of influences that vary through time. • Changes that affect the entire population irrespective of age and birth cohort (e.g. new treatments, environmental disasters, changes in policies, the economy etc.) • Cohort effects are the consequences of being born and growing up at different times. • Changes according to year of birth, irrespective of age and calendar time Blackwell encyclopedia of sociology, Ed, Ritzer G. 2007

5. Data Sources • Canadian National Population Health Survey (NPHS) • National representative longitudinal household survey • Biennial interviews from 1994/95 to 2010/11 • 9 cycles spanning 16 years • Sample of 8,570 participants in one of the birth cohorts

6. Dimensions of physical activity 1. Usual activities ‘Thinking back over the past 3 months, which of the following best describes your usual activities or work habits?’ ‘Sit during the day and don’t walk much’, ‘Stand or walk quite a lot’, ‘Lift/carry light loads’ , ‘Heavy work or carry heavy loads’ 2. Leisuretime physical activity(LTPA): at least moderate Moderate active: >1.5 kcal/kg/day1 3. Walking/cycling for commuting and errands (WCCE): at least moderate ‘In a typical week in the past 3 months, how many hours did you usually spend walking (cycling) to work or school or while doing errands?’ 1 Katzmarzyk and Tremblay (2007)

7. Statistical Analysis • Multilevel growth models • Age-trajectory of LTPA by cohort: • Not including period • Including period • Added usual activities to the APC model of LTPA previously fitted, controlling for sex, education, income, and BMI

8. Results

9. Leisure time physical activity

10. LTPA: age trajectories by cohort Cohort effect: p<0.0001 Age effect: p<0.0001 Period effect: - Predicted age- trajectory by cohort

11. LTPA: age trajectories by cohort Cohort effect: p=0.015 Age effect: p<0.0001 Period effect: p<0.0001 Predicted age- trajectory by cohort Predicted age- trajectory by cohort holding period constant

12. Usual activities

13. Leisure time physical activity : effect of changes in usual activities **Significant at p<0.001. Models included age terms, cohort, period. aAlso included sex, education, income and BMI Further analysis show a significant interaction between usual activities and sex

14. Leisure time physical activity : by categories of usual activities by sex GenX YBB Solid/Dashed: Not Sedentary/ Sedentary in usual day Dark/Light: Women/Men OBB WWII

15. Limitations • Physical activity measured in the NPHS • Self-reported nature of the data • Attrition due to drop-outs and mortality, particularly in the older cohort

16. Summary and Conclusions • In all cohorts, individuals are increasingly participating in LTPA as they grow older and this growth is due to period effect • health promotion initiatives have been somewhat successful • Members of the younger cohorts are more likely to be physically active during leisure time than their older counterparts • Generally, those who are sedentary in their usual activities are less likely to participate in LTPA • particularly women in all cohorts and men in the two oldest cohorts • The results indicate that efforts to address LTPA also need to take into account usual activities

17. Acknowledgements Canadian Institutes of Health Research Operating Grant - Secondary Analysis of Databases ‘In sickness or in health? How well are the baby boomers aging compared to older generations: an analysis of age, period and cohort effects.’ P.I. Elizabeth Badley

18. WCE: age trajectories by cohort Predicted age- trajectory by cohort

19. WCE: age trajectories by cohort Predicted age- trajectory by cohort Predicted age- trajectory by cohort holding period constant

20. Usually sedentary: age trajectories by cohort Predicted age- trajectory by cohort

21. Usually sedentary: age trajectories by cohort Predicted age- trajectory by cohort Predicted age- trajectory by cohort holding period constant