Being more physically active may reduce men’s risk of prostate cancer, according to a study in the International Journal of Epidemiology in December 2019.
British researchers analyzed data from 140,000 men, about 80,000 of whom had been diagnosed with prostate cancer. They used a research technique called Mendelian randomization, which uses genetic variations as proxies for lifestyle factors (or “exposures”) such as dietary habits, nutrient intake, and physical activity. That is, rather than relying on men’s subjective reports of what they ate or how much they exercised, the study looked at certain genes that are linked to specific nutrient levels or levels of activity.
Men who had a DNA variant associated with higher levels of physical activity were about 50 percent less likely to develop prostate cancer than men who didn’t have that variant—the largest effect of any of the 22 genetically influenced risk factors examined in the study. Unlike other observational studies, which can establish only associations (not causalities), the relationship between physical activity and prostate-cancer risk in the current study is likely causal, the authors wrote, since genes are randomly assigned at birth.
Some earlier, observational research linked vigorous exercise with a reduced risk of dying from prostate cancer.