Researchers with the Durham Veterans Affairs Medical Center in Durham NC evaluated exercise levels for just over 300 men, average age 64, using a questionnaire that measured metabolic equivalent (MET) hours per week. MET is a physiological measure expressing the energy cost of physical activity. Less than three is considered sedentary, 3 through 8.9 is mildly active, 9 through 17.9 is moderately active, and 18 or more is considered highly active.
Lionel Banez MD and colleagues found that in Caucasian men, being at least moderately active had a lower risk of being diagnosed with prostate cancer. If they did have cancer, they were significantly less likely to have high-grade disease if they worked out regularly.
Unfortunately, there was no significant link between exercise and reduced prostate cancer among the black participants, Dr. Bañez and colleagues found. The reasons, however, are not clear for the racial discrepancy. Dr. Banez suggests that there are several possible mechanisms that may play a role, including hormonal profiles and genetic susceptibilities.
Per the National Cancer Institute, African American/Black men have the highest incidence rate for prostate cancer in the United States and are more than twice as likely as White men to die of the disease.
The researchers cautioned that the cohort was small, which raises the possibility that the findings are the result of chance. In addition, factors that were not measured, such as diet, might have played a role, they added. Previous studies have found that men who eat a diet high in fat, especially animal fat, are at a greater risk for developing prostate cancer.
Prostate cancer is the most common non-skin cancer in America, affecting 1 in 6 men. Age and family history are among the most prominent risk factors for the disease.
Singh AA, et al. "Association between exercise and primary incidence of prostate cancer: Does race matter?" Cancer 2013; DOI: 10.1002/cncr.27791.