According to a new study, exercise may reduce the risk of prostate cancer; however, the benefits vary by age and ethnicity. Researchers affiliated with Duke University and Veterans Affairs Medical Center, both in Durham, North Carolina, published their findings online on February 11 in the journal cancer.
The researchers noted that previous studies have reported that regular exercise is associated with the reduction of risk for prostate cancer; however, these studies did not define racial discrepancies. Therefore, they conducted a study to compare the impact of exercise and risk among Caucasian and African American men. According to the Centers for Disease Control and Prevention (CDC), African American men are more likely to be diagnosed with prostate cancer (and ultimately die from it) than men from other ethnic groups.
The researchers conducted a prospective (forward-looking) study comprised of 307 men (Caucasian: 164; African American: 143) who were undergoing a prostate biopsy. The subjects completed a self-reported survey that assessed exercise behavior based on metabolic equivalent (MET) hours per week. The risk of prostate cancer was assessed and was controlled for age, body mass index (BMI), digital rectal examination findings, previous biopsy, Charlson comorbidity score, and family history of prostate cancer stratified by self-reported race.
The researchers found that there was no significant difference noted with regard to the amount of exercise between racial groups. Higher amounts of MET hours per week were associated with a decreased risk of prostate cancer for Caucasian men. Among Caucasians, those who exercised nine or more 9 MET hours per week were less likely to have a positive biopsy result compared with men exercising less than nine MET hours per week. However, no association was found between MET hours per week and risk of prostate cancer among African American men. They also found that moderately or highly active Caucasian men in their 60s were 53% less likely to have a prostate cancer biopsy test positive for cancer compared with those who were not very active or who were sedentary.
The researchers concluded that in a prospective cohort of men undergoing biopsy, increased exercise, measured as MET hours per week, was found to be associated with prostate cancer risk reduction among Caucasian but not African American. They recommended that further research should be conducted to investigate race-specific mechanisms by which exercise modifies prostate cancer risk and why these mechanisms disfavor African American men in particular.