Aug. 30 (Bloomberg) -- Men may halve their chances of getting an enlarged prostate gland by taking aspirin or a similar drug daily, researchers say.

The risk of developing the condition, which can cause painful urination or block it entirely, fell in patients taking so-called nonsteroidal anti-inflammatory drugs, or NSAIDs, according to a study released today by the Mayo Clinic in Rochester, Minnesota.

The finding may help men avoid the ailment, which strikes one in four males aged 40 to 50 and almost half at 70 to 80. A healthy gland isn't much bigger than a walnut. In a malady called benign prostatic hyperplasia, the prostate can grow as large as a peach, pressing on the tube that carries urine.

``This study suggests that men's urinary health may be improved by taking NSAIDs,'' said Michael Lieber, a Mayo Clinic urologist who worked on the study, in a statement.

The scientists urged further research to determine the best doses of aspirin and other drugs for preventing an enlarged prostate. The researchers, citing potential side effects of the medicines such as stomach ulcers, fell short of recommending that men now take the drugs solely for that purpose.

``We're definitely not recommending that people go out and start taking aspirin or other NSAIDs to prevent prostate disease,'' said Jenny St. Sauver, the study's lead investigator, in a telephone interview on Aug. 28.

Gathering Data

In the observational study, the researchers didn't assign any drugs to patients. Instead, they gathered data on 2,447 men Minnesota who completed questionnaires every two years from 1990 to 2002. One-third of the men studied were taking painkillers daily when they were enrolled in the study.

The study showed that the risk of developing moderate to severe urinary symptoms was 35 percent lower in those taking the painkillers, the researchers reported.

Many men already take NSAIDs. The drugs are used primarily to relieve arthritis symptoms, including inflammation, stiffness and joint pain, according to the U.S. National Institutes of Health, based in Bethesda, Maryland.

Some men are using dietary supplements and herbal medicines to prevent or treat prostate disease, according to the Mayo Clinic Web site. Products that are marketed to relieve prostate problems including African plum tree, African wild potato and stinking nettle, according to the Web site. The herb saw palmetto can reduced symptoms of enlarged prostate.

Prescription-drug treatments available once somebody has an enlarged prostate include Flomax, from closely held Boehringer Ingelheim GmbH, based in Ingelheim, Germany; and Proscar, from Merck & Co., based in Whitehouse Station, New Jersey. Patients whose cases don't respond to drugs often require surgery, often to scrape away the core of the prostate to lessen pressure.

The Mayo study was posted on Aug. 11 on an American Journal of Epidemiology Web page available only to subscribers to the journal. The study will also appear in a forthcoming issue of the publication's print edition. Mayo provided a copy of the study for public release today.

To contact the reporter on this story: Nicole Ostrow in New York at nostrow@bloomberg.net.

Last Updated: August 30, 2006 00:05 EDT