Background: The possible benefit of lifetime physical activity (PA) in reducing prostate cancer incidence and mortality is unclear.
Methods: A prospective cohort of 45,887 men aged 45-79 years was followed up from January 1998 to December 2007 for prostate cancer incidence (n=2735) and to December 2006 for its subtypes and for fatal (n=190) prostate cancer.
Results: We observed an inverse association between lifetime (average of age 30 and 50 years, and baseline age) total PA levels and prostate cancer risk. Multivariate-adjusted incidence in the top quartile of lifetime total PA decreased by 16% (95% confidence interval (CI)=2-27%) compared with that in the bottom quartile. We also observed an inverse association between average lifetime work or occupational activity and walking or bicycling duration and prostate cancer risk. Compared with men who mostly sit during their main work or occupation, men who sit half of the time experienced a 20% lower risk (95% CI=7-31%). The rate ratio linearly decreased by 7% (95% CI=1-12%) for total, 8% (95% CI=0-16%) for localised and 12% (95% CI=2-20%) for advanced prostate cancer for every 30 min per day increment of lifetime walking or bicycling in the range of 30 to 120 min per day.
Conclusions: Our results suggest that not sitting for most of the time during work or occupational activity and walking or bicycling more than 30 min per day during adult life is associated with reduced incidence of prostate cancer.