The Epidemiology of Physical Activity in Canada

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Bryan, Shirley
Leisure-Time Physical Activity , Physical Activity Guidelines
The four studies of this thesis provide an overview of the epidemiology of physical activity in Canada. In the first study two methods of coding activities used in estimating leisure-time physical activity energy expenditure (LTPAEE), from a questionnaire including 21 specific activities, and up to three “other” activities were compared. The authors assessed whether the assignment of activity intensity for “other” activities has an effect on LTPAEE and the classification of respondents as physically active versus inactive. The results indicate that the population classification of activity level is not affected by the intensity code; however, individual level LTPAEE is under-estimated from light and vigorous activities and over-estimated from moderate activities using the current method. In study two the proportion of Canadians meeting Canada’s physical activity guidelines for moderate and vigorous activities was estimated. The prevalence of adults reporting no activity has not changed since 1994/95 and the prevalence of meeting the guidelines has increased by about 11%. Men, younger adults, those with higher income and lower body mass index (BMI) meet the guidelines more often than their peers. The epidemiology of walking among Canadians between 1994 and 2007 was assessed in the third study. Walking was the most popular activity, regardless of age, sex, BMI or income group; however, only 30% of walkers walked regularly. Women, older adults, those with lower BMI and lower household income walk regularly more often than their counterparts. Women, older adults and lower income Canadians tended to derive 100% of their total LTPAEE from walking. An evaluation of whether meeting the guidelines for physical activity was associated with lower odds of chronic conditions and reporting fair/poor health was undertaken in study four. After adjustment for covariates, the odds of type 2 diabetes, obesity and reporting fair/poor health were significantly higher among those not meeting the guidelines for both sexes and for high blood pressure among women. Together these findings provide an understanding of the limitations of estimating LTPAEE, provide estimates of the proportion of Canadians meeting the guidelines for physical activity and provide insight into the relationship between meeting the guidelines and chronic conditions.
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