Why aged men become impotent.

Despite frequent erectile impotence in aged men, etiologic data are scarce. We evaluated 121 impotent male veterans (mean age, 68 +/- 5.3 years) to obtain information on potential pathophysiologic mechanisms. Subjects related a complete medical history and underwent physical examination, metabolic assessment, nocturnal penile tumescence monitoring, and vascular and neurologic assessment. The most frequent cause of impotence was the coexistence of neurologic and vascular disorders (30.3%). Other subjects had single causes, including vascular disease (21.1%), diabetic neuropathy (17.1%), nondiabetic neuropathy (10.5%), and psychopathology (9.2%). Remaining patients suffered from adverse drug effects (3.9%), hypogonadism (2.6%), and Peyronie's disease (1.3%). Five patients were objectively impotent on the basis of nocturnal penile tumescence, but otherwise normal. We conclude that geriatric impotence is primarily related to vascular or neurologic dysfunction. However, 15.7% of aged impotent men may have reversible impotence (eg, psychogenic causes or hypogonadism), and an additional 31.5% may have a treatable disorder (eg, penile neuropathy).