Changes in sexual function in middle-aged and older men: Longitudinal data from the Massachusetts Male Aging Study

Objectives: 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. Design: Cohort study; participants interviewed at baseline (1987-89) and follow-up (1995-97). Setting: Population-based; communities surrounding Boston, Massachusetts. Participants: 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. Measurements: 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. Conclusion: 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.