Use of cholesterol-lowering statin drugs, especially long-term use, appears to raise the risk of prostate cancer among obese men, according to findings of a new study.

“Given the epidemic of obesity in the U.S. and the frequent use of statins, the positive association we observed raises substantial concern as to the safety of these widely prescribed agents,” Dr. Janet L. Stanford of the Fred Hutchinson Cancer Research Center in Seattle and colleagues wrote in the American Journal of Epidemiology.

In a population-based, case-control study, the researchers matched 1,001 men with prostate cancer diagnosed between 2002 and 2005 with 942 age-matched cancer-free controls from King County, Washington.

No overall association was observed between the risk of prostate cancer and the current or past use of statin treatment. Duration of statin use was also not associated with prostate cancer risk.

“We also found no evidence that use of a statin was associated with risk of developing more aggressive subtypes of prostate caner,” Stanford said in an interview with Reuters Health. “Overall we found no support for the current hypothesis that statin use may reduce risk of prostate cancer.”

However, the results do suggest a significant increase in the risk of developing prostate cancer associated with current statin use and with longer durations of use among obese men (defined as a body mass index of 30 greater).

“Among obese men,” Stanford told Reuters Health, “current use of a statin was associated with a 50 percent increase in risk of prostate cancer; and use for 5 or more years was associated with an 80 percent increase in risk of the disease; both of these risk estimates were statistically significant.”

These findings warrant further investigation, she said.

SOURCE: American Journal of Epidemiology, August 1, 2008.