Case-control study of lifetime total physical activity and prostate cancer risk.

A population-based case-control study of physical activity and prostate cancer risk was conducted in Alberta, Canada, between 1997 and 2000. A total of 988 incident, histologically confirmed cases of stage T2 or greater prostate cancer were frequency matched to 1,063 population controls. The Lifetime Total Physical Activity Questionnaire was used to measure occupational, household, and recreational activity levels from childhood until diagnosis. Multivariable logistic regression analyses were conducted. No association for total lifetime physical activity and prostate cancer risk was found (odds ratio (OR) for > or =203 vs. <115 metabolic equivalent-hours/week/year=0.87, 95% confidence interval (CI): 0.65, 1.17). By type of activity, the risks were decreased for occupational (OR=0.90, 95% CI: 0.66, 1.22) and recreational (OR=0.80, 95% CI: 0.61, 1.05) activity but were increased for household (OR=1.36, 95% CI: 1.05, 1.76) activity when comparing the highest and lowest quartiles. For activity performed at different age periods throughout life, activity done during the first 18 years of life (OR=0.78, 95% CI: 0.59, 1.04) decreased risk. When activity was examined by intensity of activity (i.e., low, <3; moderate, 3-6; and vigorous, >6 metabolic equivalents), vigorous activity decreased prostate cancer risk (OR=0.70, 95% CI: 0.54, 0.92). This study provides inconsistent evidence for the association between physical activity and prostate cancer risk.