Leisure-time sedentary behavior is an emerging modifiable risk factor for cancer. We estimated the proportion of cancers attributed to leisure-time sedentary behavior as a separate risk factor from physical activity in Canada for 2015. We projected numbers of future avoidable cancers by 2042 using various assumed levels of reduced leisure-time sedentary behavior in the population. We calculated population attributable risks (PAR) for associated cancers and all-cancers associated with leisure-time sedentary behavior. Our analysis used pooled data on leisure-time sedentary behavior from the Canadian Community Health Survey (CCHS), and incident cancer data from the Canadian Cancer Registry (CCR). Survey respondents were categorized into three levels of leisure-time sedentary behavior, “<3 h/day”, “≥3–<6 h/day”, and “≥6 h/day”. Estimates for the future burden of leisure-time sedentary behavior were calculated using the potential impact fractions framework (PIF) and counterfactual scenarios, from 10% to 50% decreases in leisure-time sedentary behavior. The estimated prevalence of leisure-time sedentary behavior at the highest level (≥6 h/day) in Canada during the 2000s was 9.9% among both sexes combined across age-groups. The total attributable burden due to leisure-time sedentary behavior was estimated to be 10.3% for associated cancers and 6.5% for all-cancers in 2015. A 50% reduction in leisure-time sedentary behavior across the Canadian population could avoid 4054 cancers by 2042. We estimated that over 3000 cancer cases in Canada were attributable to leisure-time sedentary behavior in 2015, and that that 4054 incident cancer cases could be prevented by 2042 with meaningful reductions in leisure-time sedentary behavior.

Cancer risk, Population attributable risk, Potential impact fraction, Prevention, Sedentary behavior
Preventive Medicine
Department of Health Sciences

Friedenreich, C.M. (Christine M.), Pader, J. (Joy), Barberio, A.M. (Amanda M.), Ruan, Y. (Yibing), Poirier, A.E. (Abbey E.), Grevers, X. (Xin), … Brenner, D.R. (Darren R.). (2019). Estimates of the current and future burden of cancer attributable to sedentary behavior in Canada. Preventive Medicine. doi:10.1016/j.ypmed.2019.03.009