The finding, presented at the annual meeting of the American Urological Association, provides additional insight into the effects statins have on the prostate. Previous studies at Duke and elsewhere had found a link between the cholesterol drugs and lower levels of PSA, a protein produced by the prostate that is often elevated by cancer or by non-lethal prostatic diseases.
In the current finding, prostatic growth rate diminished among men with elevated PSA levels who took statins, although that effect was relatively small and tapered off after about two years.
“Given that benign prostate growth is an important health problem in the United States and elsewhere, and will be a larger problem as the population ages, it’s important to understand and treat its causes,” said Roberto Muller, M.D., a urology fellow at Duke and lead author of the study.
Enlarged prostate, diagnosed as benign prostate hyperplasia, causes urinary problems that can escalate to bladder and kidney damage. Up to 90 percent of men over the age of 70 have some symptoms associated with enlarged prostate, according to the National Institutes of Health.
Muller and colleagues used data gathered for an unrelated, large trial testing a drug called dutasteride, which can be used to treat prostate enlargement. From that trial, the researchers culled data for more than 6,000 men, including 1,032 who also took statins. Men on statins were older on average than non-users, but had a similar prostate volume.
At two years, prostate growth was less for the men in the study who took a statin drug, regardless of whether they had been randomly assigned to take dutasteride or a dummy pill. In men who took both a statin and dutasteride pill, prostate growth was 5 percent less than in untreated men. For those taking a statin and a dummy pill, prostate growth was 3.9 percent less.
Those reductions, however, did not persist after two years.
“We don’t yet understand the mechanisms that might be causing this,” Muller said. “Some have suggested that statins may have anti-inflammatory properties, and inflammation has been linked to prostate growth, but this needs further study.”
Muller said the findings in the current research also suggest that lifestyle choices such diet and exercise may not only affect cholesterol, but also prostate health.
“Prostate enlargement was once considered an inexorable consequence of aging and genetics, but there is growing awareness that prostate growth can be influenced by modifiable risk factors,” Muller said. “In this context, the role of blood cholesterol levels and cholesterol-lowering drugs such as statins warrants further study.”
In addition to Muller, study authors included Leah Gerber; Daniel Moreira; Gerald Andriole; J. Kellogg Parsons; Neil Fleshner; and Stephen Freedland.
The study was funded by GlaxoSmithKline, which markets dutasteride.