physical activity of baby boomers compared to older and younger generations in canada:

Physical activity of baby boomers compared to older and younger

generations in Canada: An age-period-cohort analysis

Mayilee Canizares, 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 AssociationMay 2014

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.

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.

Objectives

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 timePeriod 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

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

Year of Birth

Age at baseline

World War II (WW) 1935 – 1944 50-59Older baby boomer (OBB) 1945 – 1954 40-49Younger baby boomer (YBB): 1955 – 1964 30-39Generation X (GenX): 1965 – 1974 20-29

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. Leisure time physical activity(LTPA): at least moderateModerate 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)

Dimensions of physical activity

Statistical Analysis

Multilevel growth models

Age-trajectory of LTPA by cohort: o Not including periodo Including period

Added usual activities to the APC model of LTPA previously fitted, controlling for sex, education, income, and BMI

Results

GenX YBB OBB WW0

10

20

30

40

50

1994 2010

Prop

ortio

n (%

)Leisure time physical activity

Predicted age- trajectory by cohort

LTPA: age trajectories by cohort

0

10

20

30

40

50

60

70

GenX YBBOBB WW

Age (years)

Pred

icted

pro

porti

on (%

)

Cohort effect: p<0.0001Age effect: p<0.0001Period effect: -

Predicted age- trajectory by cohort holding period constantPredicted age- trajectory by cohort

LTPA: age trajectories by cohort

0

10

20

30

40

50

60

70

GenX YBBOBB WW

Age (years)

Pred

icted

pro

porti

on (%

)

Cohort effect: p=0.015Age effect: p<0.0001Period effect: p<0.0001

Usual activities

GenX YBB OBB WW0

10

20

30

40

50

1994 2010

Prop

ortio

n (%

)

Leisure time physical activity : effect of changes in usual activities

Odd Ratio (95% CI)

Usual activities: sedentary

0.73**

(0.71 – 0.74)

**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

0

20

40

60

80

Pred

icted

LTPA

(%)

0

20

40

60

80

Pred

icte

d LT

PA (%

)

0

20

40

60

80

Pred

icted

LTPA

(%)

0

20

40

60

80Pr

edic

ted

LTPA

(%)

GenX YBB

OBB WWII

Leisure time physical activity : by categories of usual activities by sex

Solid/Dashed: Not Sedentary/ Sedentary in usual day

Dark/Light: Women/Men

Physical activity measured in the NPHS Self-reported nature of the data Attrition due to drop-outs and mortality,

particularly in the older cohort

Limitations

In all cohorts, individuals are increasingly participating in LTPA as they grow older and this growth is due to period effecto 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 o 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

Summary and Conclusions

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

Acknowledgements

0

5

10

15

20

25

30

Age (years)

Pred

icte

d pr

opor

tion

(%)


WCE: age trajectories by cohort

WCE: age trajectories by cohort

0

5

10

15

20

25

30

Age (years)

Pred

icte

d pr

opor

tion

(%)


20 24 28 32 36 40 44 48 52 56 60 64 68 72 760

5

10

15

20

25

30

Age (years)

Pred

icted

pro

porti

on (%

)


Usually sedentary: age trajectories by cohort

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