April 16, 2010 -- Statin therapy prescribed to lower cholesterol also appears to lower testosterone, according to a new study that evaluated nearly 3,500 men who had erectile dysfunction or ED.

''Current statin therapy is associated with a twofold increased prevalence of hypogonadism," a condition in which men don't produce enough testosterone, study author Giovanni Corona, MD, PHD, a researcher at the University of Florence in Italy, tells WebMD.

Although previous studies have produced mixed findings on the possible link between taking cholesterol-lowering drugs and a drop in testosterone, most involved a limited number of patients, with few studies including more than 50 people, Corona says.

"Our study is the first report showing a negative association between statin therapy and testosterone levels in a large series of patients consulting for sexual dysfunction," he says.

About one of six adults in the U.S. has high cholesterol, according to the CDC. The number of people buying a statin (such as Lipitor or Zocor) rose 88% from 2000 to 2005, from 15.8 million people to 29.7 million, according to the federal Agency for Healthcare Research and Quality.