The longitudinal relationship of sexual function and androgen status in older men: the Concord Health and Ageing in Men Project.

Abstract

It is unclear whether declining sexual function in older men is a cause or consequence of reduced androgen status. Longitudinal associations were examined between reproductive hormones and sexual function in older men. Men aged 70 years and older from the Concord Health and Ageing in Men Project study were assessed at baseline (n = 1705) and 2-year follow-up (n = 1367), with a total of 1226 men included in the final analyses. At both visits, serum testosterone (T), dihydrotestosterone (DHT), estradiol (E2), and estrone (E1) were measured by liquid chromatography-tandem mass spectrometry, and SHBG, LH, and FSH were measured by immunoassay. Sexual functions (erectile function, sexual activity, and sexual desire) were self-reported via standardized questions. In longitudinal analyses, although baseline hormones (T, DHT, E2, and E1) did not predict decline in sexual function, the decline in serum T (but not DHT, E2, or E1) over 2 years was strongly related to the change in sexual activity and desire (but not erectile function). For each 1-SD decrease in T from baseline to 2-year follow-up, there was a multivariate-adjusted odds ratio of 1.23 (95% confidence interval, 1.12-1.36) for an additional risk of further decline in sexual activity. However, the magnitude of the decrease in serum T was strikingly small (<10%). Similar associations were found for changes over 2 years in serum T and decline in sexual desire, but not for erectile function. We found a consistent association among older men followed over 2 years between the decline in sexual activity and desire, but not in erectile function, with a decrease in serum T. Although these observational findings cannot determine causality, the small magnitude of the decrease in serum T raises the hypothesis that reduced sexual function may reduce serum T rather than the reverse.