Physical activity does not increase risk of urological cancer
No association exists between physical activity and the risk of urological cancer, according to a population-based prospective study in Japan.
The authors enrolled a total of 76,795 Japanese adults (aged 45–74 years) and evaluated the participants’ physical activity using a self-administered questionnaire. Cox proportional hazards models were generated to calculate the hazard ratios (HRs) and 95 percent CIs of the urological cancer risk.
There were 202 kidney, 373 bladder and 83 upper urinary tract cancer cases recorded over a follow-up period of 15.1 years. Physical activity did not significantly correlate with kidney (HR, 1.05; 95 percent CI, 0.74–1.49), bladder (HR, 1.06; 0.81–1.39) and upper urinary tract (HR 0.80; 0.48–1.35) cancer risks.
A previous study including 79,771 Japanese men and women (aged 45–74 years) found that increased daily physical activity significantly reduced the risk of cancer in both sexes. The risk decrease was more clearly seen in women than in men, particularly among elderly adults and those who regularly engaged in leisure-time sports or exercise. [Am J Epidemiol 2008;168:391-403]
Furthermore, another study claimed increased physical activity lowers the risk for all-cause death in a Japanese population. [J Epidemiol 2009;19:24-7]
Analysis by site revealed that the reduced risks were observed for cancers of the colon, liver and pancreas in men and for cancer of the stomach in women. Researchers suggested that increased daily physical activity confers a protective effect against cancer in a relatively lean population.