Although no one knows how many men have prostatitis, experts think it is the most common genitourinary ailment in men younger than age 50, and the chronic abacterial form-for which there is no known cause and no diagnostic test or reliable treatment-predominates. Prostatitis occurs in men of all ages and races and accounts for an estimated 2 million visits to doctors each year, according to a national survey.

Abacterial prostatitis is a syndrome of pain in the genital area and lower back, usually accompanied by frequent and urgent urination. It can effectively chain severely affected men to their bathrooms. Other symptoms such as burning or pain during voiding or ejaculation vary widely and may come and go without warning. The walnut-sized prostate sits forward of the rectum, below the bladder and surrounding the urethra, the tube through which urine passes out of the body.

"It's amazing to me that we can't reliably treat the majority of men who have prostatitis. We hope this study will help us do a better job diagnosing and treating these men in the future, but we recognize the road ahead will probably be quite unpredictable," said Leroy M. Nyberg Jr., Ph.D., M.D., NIDDK study director.

From November 9 through October 2001, six medical centers will recruit more than 600 men for the Chronic Prostatitis Cohort Study. This will be the first large, multicenter study designed to gather well-defined, detailed, clinical information on the condition and then use that base to test and evaluate new treatment strategies in the future. The study will document symptoms, possible risk factors, medical histories and treatments; test blood, prostate fluid, semen and urine; and explore possible relationships between chronic prostatitis, urethral and bladder inflammation and other chronic pelvic pain disorders. Results are anticipated after September 2002.

Desperate for relief, many men with chronic prostatitis are driven--sometimes far from home--to expensive, unproven and often disappointing remedies. The often- prescribed, powerful antibiotics and drugs to relax the muscles of the prostate, in fact, often fail.

Earlier studies observed small numbers of patients over short periods and used varying definitions, so that results were unclear and not comparable between studies. Besides focusing on hundreds of patients over 3 years, doctors in this study are also testing a new working definition of chronic abacterial prostatitis developed by consensus by researchers, physicians and patients at an NIDDK workshop in 1995.

Patients may contact the nearest participating center for more information.