title: Changes in sexual function in middle-aged and older men: longitudinal data from the Massachusetts Male Aging Study.
abstract: OBJECTIVE
  To describe within-individual change in sexual function over a 9-year period and to determine whether the amount of change differs by age group.
  
  
  METHODS
  Cohort study; participants interviewed at baseline (1987-89) and follow-up (1995-97).
  
  
  METHODS
  Population-based; communities surrounding Boston, Massachusetts.
  
  
  METHODS
  One thousand eighty-five men aged 40 to 70 at baseline (born between 1917 and 1947) with complete baseline and follow-up sexual function data.
  
  
  METHODS
  Within-person change (follow-up minus baseline) in the following sexual function variables: sexual intercourse, erection frequency, sexual desire, ejaculation with masturbation, satisfaction with sex, and difficulty with orgasm.
  
  
  RESULTS
  Unadjusted analyses showed significant longitudinal changes over the 9-year period in all domains of sexual function except frequency of ejaculation with masturbation, which showed no change between baseline and follow-up. Adjusted for baseline sexual function, within-person change in all outcomes was strongly related to age, with decline in sexual function becoming more pronounced with increasing age. For example, over the 9-year study period, sexual intercourse or activity frequency decreased by less than once per month, two times per month, and three times per month in men in their 40s, 50s, and 60s, respectively. Number of erections per month declined by 3, 9, and 13 in men in their 40s, 50s, and 60s, respectively.
  
  
  CONCLUSIONS
  This research fills a major gap in the literature by providing age-specific estimates of change in sexual functioning over a 9-year period in a cohort of unselected men.
authors.affiliation: New England Research Institutes, Watertown, Massachusetts 02472, USA. AndreA@neri.org
authors.forename: Andre B
authors.initials: AB
authors.lastname: Araujo
authors.forename: Beth A
authors.initials: BA
authors.lastname: Mohr
authors.forename: John B
authors.initials: JB
authors.lastname: McKinlay
mesh_terms: D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology / Q000523:psychology; D001900:Boston / Q000453:epidemiology; D003075:Coitus; D015986:Confounding Factors, Epidemiologic; D004542:Ejaculation; D007172:Erectile Dysfunction / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D009948:Orgasm; D010410:Penile Erection; D010549:Personal Satisfaction; D011159:Population Surveillance; D012016:Reference Values; D012307:Risk Factors; D012725:Sexual Behavior / Q000502:physiology / Q000523:psychology / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D013997:Time Factors