A new surrogate variable for erectile dysfunction status in the Massachusetts male aging study

Erectile dysfunction (ED) is the subject of a vast clinical literature, but little information has been gathered from random samples of the general pu blic. The Massachusetts Male Aging Study (MMAS) addressed this important as pect of men's health. The MMAS was conducted in two waves, with baseline da ta collection in 1987-1989 and follow-up in 1995-1997. Subsequent to the ba seline MMAS survey, a consensus developed that subjective measures are opti mal for defining ED. Unfortunately, the baseline questionnaire did not ask subjects directly about their erectile functioning. Thus, we previously ass igned the MMAS subjects a degree of impotence at baseline using a series of related questions, employing a discriminant formula constructed from a sep arate sample of urology clinic patients. At follow-up the men classified th emselves directly in addition to answering the original series of related q uestions. In the present article, we report the results of a new discrimina nt function, based on the MMAS men at follow-up. We also compare the two me thods and discuss our reasons for preferring the internally calibrated meth od. (C) 2000 Elsevier Science Inc. All rights reserved.