Study Shows Coffee’s Benefits

The consumption of coffee and vigorous exercise may have a hand in decreasing the risk of prostate cancer, according to separate findings recently presented by two researchers affiliated with the Harvard School of Public Health.

Kathryn M. Wilson, a research fellow in the epidemiology department at HSPH, found a correlation between the consumption of coffee and a decreased risk of the cancer, which afflicts more men than any other cancer, according to the Centers for Disease Control and Prevention. Meanwhile, Stacey A. Kenfield, a research associate in the department, determined that vigorous exercise may reduce the risk of mortality due to the same disease.

For her study, Wilson tracked the coffee consumption habits of 50,000 men ranging in age from their mid-50s to mid-70s, finding that men who regularly drank coffee over the 20-year span of the study developed advanced prostate cancer at a lower rate than non-coffee drinkers.

Subjects who reported consuming six or more cups of coffee every day were found to have a 60 percent lower chance of advanced or lethal prostate cancer than those who did not drink coffee. Both regular and decaffeinated coffee elicited the same results.

The study also found that men who drink large amounts of coffee are more likely to smoke, exercise less, and be overweight—factors that have been shown to increase the risk of prostate cancer. Wilson said these findings added support to her belief that coffee itself—and not, for instance, the life style choices related to the drink—may be responsible for the link between coffee consumption and the lower risk of prostate cancer.

But Wilson said that the study did not investigate the reasons behind the coffee-cancer connection.

“You can’t really say that this is a direct cause-and-effect relationship,” Wilson said, adding that she thinks the results may be somehow related to coffee’s association with a lower risk of Type II diabetes.

Other studies have shown that drinking coffee potentially decreases the risk of liver and endometrial cancer as well, according to Wilson. But despite all the potential benefits of coffee, more research needs to be done before people are encouraged to reevaluate their drinking choices, Wilson said.

“I don’t think there is a reason to change your coffee drinking habits in either direction,” she said.

Kenfield’s study—which followed 2,686 men who had already been diagnosed with prostate cancer and quantified their exercise habits after their diagnoses—found that vigorous activity decreased the risk of mortality due to prostate cancer.

Those who participated in non-vigorous activities equivalent to about 30 minutes of jogging, biking, or swimming per week, saw a 35 percent reduction in overall mortality, according to Kenfield. But these exercises had no measurable effect on the risk of mortality due to prostate cancer.

By contrast, those who participated in vigorous activities experienced a 12 percent decreased risk of mortality specifically due to prostate cancer. Kenfield said she plans to do more research to determine the cause of the results, focusing on insulin pathways and insulin growth factors.

Though the causality of the study’s results has yet to be determined, Kenfield said that the positive health benefits attributed to exercise make it a sensible habit for men with prostate cancer to adopt.

Wilson and Kenfield presented their findings last Monday in Houston at the American Association for Cancer Research’s “Frontiers in Cancer Prevention” Research Conference.

—Staff writer Ryan D. Smith can be reached at rdsmith@fas.harvard.edu