Mayo Clinic finds aspirin, other NSAIDs, may prevent or delay enlarged prostate

ROCHESTER, Minn. -- Mayo Clinic researchers have found that taking nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen may prevent or delay benign prostatic hyperplasia, an enlarged prostate which can cause urinary symptoms in men as they age such as frequent urination, trouble starting urination, awakening frequently at night to urinate, weak urine stream and an urgent need to urinate. Details will be published in the American Journal of Epidemiology.

"This study suggests that men's urinary health may be improved by taking NSAIDs," says Michael Lieber, M.D., Mayo Clinic urologist and study investigator. He and colleagues found the risk of developing an enlarged prostate was 50 percent lower in NSAID users compared to non-users, and risk of developing moderate to severe urinary symptoms was 35 percent lower, he says.

Jenny St. Sauver, Ph.D., Mayo Clinic epidemiologist and lead study investigator, says, "The association between intake of NSAIDs and the reduction of benign prostatic hyperplasia is strengthened by the consistency and magnitude of our findings. We would not recommend that every man go out and take aspirin, but if they are already taking it regularly for other reasons, our findings suggest another benefit as well."

Benign prostatic hyperplasia increases as men age, affecting one in four men ages 40 to 50 and almost half of 70- to 80-year-old men. The condition is most often diagnosed when men visit their physicians due to urinary problems that are prompted by the prostate enlargement this condition produces.

"The typical scenario with benign prostatic hyperplasia is that men start getting up three to five times a night to urinate, and their wives ultimately force them to go see a urologist," says Dr. Lieber. "Men also might come in if they have problems with daytime urinary frequency. All this adversely affects men's quality of life."

According to Dr. Lieber, middle-aged people commonly take an NSAID in over-the-counter or prescription form to prevent heart disease or reduce arthritis symptoms.

"Our study suggests that one potential unintended consequence of so many people in our society taking NSAIDs could be an improvement in urinary health for men," he says. "So, if a person's primary care doctor recommends NSAIDs for some other reason, prostate health might be an additional benefit. However, I would not recommend taking daily NSAIDs based on this study alone, due to the potential side effects such as stomach ulcers."

NSAID dosage did not seem to affect the reduction of urinary symptoms. Only a small number of men in the study took low-dose aspirin, but even those seemed to be at decreased risk of urinary symptoms, according to Dr. St. Sauver. The type of NSAID also seemed inconsequential to the result. The majority of men studied -- 80 percent -- were taking aspirin, but those taking nonaspirin NSAIDs also experienced a risk reduction for benign prostatic hyperplasia and its urinary symptoms compared to non-NSAID users.

How NSAIDs may affect benign prostatic hyperplasia and its urinary symptoms is not known, according to Dr. Lieber. Theories, according to Dr. St. Sauver, include: 1) NSAIDs reduce prostate growth directly or by increasing cell death in the prostate, or 2) NSAIDs reduce inflammation in the genitourinary tract, the group of organs, including the prostate, involved in sexual reproduction and urination.

Several studies reporting a decreased risk of prostate cancer for men who took NSAIDs prompted the Mayo Clinic researchers' interest in testing the impact of NSAID intake on benign prostate hyperplasia. Dr. St. Sauver and colleagues studied 2,447 Caucasian men randomly selected in Olmsted County, home of Mayo Clinic. Participants completed questionnaires biennially from 1990 to 2002, including information on daily NSAID use. A random subgroup also participated in a medical evaluation that included PSA (prostate-specific antigen) level assessment and transrectal ultrasound, in which a small probe is inserted into the rectum to obtain images of the prostate gland. One-third of the men studied were taking daily NSAIDs when they enrolled in the study.

The Mayo Clinic researchers indicate that the results of their study need replication in further studies. If these results are consistent in other populations, further studies also should investigate the best dosage of NSAIDs to reduce the development of benign prostatic hyperplasia, says Dr. St. Sauver.