Meta-analysis suggests exercise reduces prostate cancer risk
MedWire News: Physical activity is associated with a small but significant reduction in the risk for prostate cancer, research shows.
The findings add to the growing body of epidemiologic evidence suggesting that physical activity protects against the development of prostate cancer, according to study author Stacey Young-McCaughan (University of Texas Health Science Center, San Antonio, USA).
"The role of physical activity in the prevention of prostate cancer has still not been clearly elucidated, but research conducted over the past 35 years continues to suggest that there is a link," she states in the World Journal of Urology.
In a recent review of 24 studies published in 2001, 14 studies suggested that physical activity reduced the risk for prostate cancer, while six found no association. The remaining four studies showed a higher risk for prostate cancer among the most physically active men.
In this latest update of the epidemiologic evidence, Young-McCaughan identified 22 studies that investigated the role of physical activity in the prevention of prostate cancer.
Thirteen studies were conducted in North America, eight were conducted in Europe, and one study in Asia. The number of men included in the studies ranged from 190 to 2 million.
Of the 22 studies, 12 showed that physical activity reduced the risk for prostate cancer, nine studies found no association between physical activity and cancer risk, and one study found an increased risk for prostate cancer with physical activity.
Among the 12 studies that found physical activity reduced the risk, the effect size was considered small, ranging from a 1% to a 49% reduction in risk, in eight studies.
One study showed that physical activity reduced the risk for prostate cancer to a moderate extent. A moderate reduction was defined as a reduction in risk ranging from 50% to 79%.
"Overall, the findings from these studies suggest that the higher levels of exercise are protective against the development of prostate cancer," writes Young-McCaughan.
She notes that the prevention of prostate cancer with physical activity might be the result of weight control.
In addition, Young-McCaughan recommends future prospective randomized clinical trials to ascertain the effects of exercise on prostate cancer risk reduction. However, she notes that these trials are expensive, require large numbers of patients, and extensively documented follow-up.
Such trials might even prove impossible given that it would be unethical to randomize patients to "no exercise" when exercise is known to provide myriad health benefits, she added.
By MedWire Reporters