Association between family history of benign prostatic hyperplasia and urinary symptoms: results of a population-based study.

Baseline measurements for a population-based prospective cohort study were used to assess the association between family history of enlarged prostate and urinary symptoms. Between December 1989 and March 1991, a group of randomly selected men aged 40-79 years from Olmsted County, Minnesota, was administered a previously validated questionnaire that included questions with wording close to that of the American Urological Association's Symptom Index. A detailed family history of an enlarged prostate was obtained by personal interview, and peak urinary flow rates were measured for each participant. Of the 2,119 men, 440 (21 percent) reported a family history of an enlarged prostate. The age-adjusted odds of having moderate or severe urinary symptoms were elevated among those with a family history relative to those without (odds ratio = 1.3, 95 percent confidence interval 1.1-1.7). With simultaneous control for effects of age and worry about urologic function, the odds ratio remained at 1.3 (95 percent confidence interval 1.0-1.6). Furthermore, this risk was greater for men with relatives diagnosed at a younger age (odds ratio = 2.5, 95 percent confidence interval 1.5-4.3). Men with a family history were also 1.3 times as likely to have an impaired peak urinary flow rate. These findings suggest that men with a family history of an enlarged prostate may be at increased risk for development of symptoms and signs suggestive of benign prostatic hyperplasia and that this risk is greater in men with relatives diagnosed at a younger age. Recognition of this association may help to target early interventions and may lead to further clues about the causes of benign prostatic hyperplasia.