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

Ken P. Kleinman, Henry A. Feldman, Catherine B. Johannes, Carol A. Derby, John B. McKinlay

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


Erectile dysfunction (ED) is the subject of a vast clinical literature, but little information has been gathered from random samples of the general public. The Massachusetts Male Aging Study (MMAS) addressed this important aspect of men's health. The MMAS was conducted in two waves, with baseline data collection in 1987-1989 and follow-up in 1995-1997. Subsequent to the baseline MMAS survey, a consensus developed that subjective measures are optimal for defining ED. Unfortunately, the baseline questionnaire did not ask subjects directly about their erectile functioning. Thus, we previously assigned the MMAS subjects a degree of impotence at baseline using a series of related questions, employing a discriminant formula constructed from a separate sample of urology clinic patients. At follow-up the men classified themselves directly in addition to answering the original series of related questions. In the present article, we report the results of a new discriminant function, based on the MMAS men at follow-up. We also compare the two methods and discuss our reasons for preferring the internally calibrated method. (C) 2000 Elsevier Science Inc.

Original languageEnglish (US)
Pages (from-to)71-78
Number of pages8
JournalJournal of Clinical Epidemiology
Issue number1
StatePublished - Jan 2000
Externally publishedYes


  • Aging
  • Discriminant analysis
  • Erectile dysfunction
  • Men
  • Population study
  • Prevalence

ASJC Scopus subject areas

  • Epidemiology


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