In men (aged 50 - 74 yrs., waist circumference (WC) ≥95cm, prediabetes or newly diagnosed T2D, and serum testosterone (T) ≤14 nmol/L), enrolled in Weight-Watchers, 2 years T-undecanoate treatment (TTr) (n=504) reduced WC and T2D risk and improved erectile function (EF) and sexual desire (SD) vs placebo (n=503) (1).
In a secondary analysis, we determined the effects of (i) baseline factors, (ii) TTr with adjustment for WC, blood pressure (BP), serum glucose, and mood over time, on EF and SD, and (iii) predictors of clinically significant effects.
Measurements: EF and SD (International Index of Erectile Function 15 questionnaire), serum trough T (LCMS/MS), glucose, WC, BP, (weeks 0, 30, 54, 78, 102), and mood (Center for Epidemiologic Studies (CES-D) questionnaire), (weeks 0, 54, 102). Clinically significant (CS) increases in SD and EF: ≥ 2 and ≥4 points respectively (2). Analyses: Linear mixed effects models, and logistic regression for CS effects.
At baseline, there were inverse associations of SD and EF with age (P<0.001), EF with WC (P=0.04), and SD with CES-D scores (P=0.03). TTr increased mean EF and SD scores, independent of baseline serum T (P<0.001); CS responses were more likely in those with low baseline EF and SD scores (P<0.001). TTr increased mean SD scores (Pint=0.014) and CS SD (P=0.011) more in older men; and maintained mean but not CS SD in those with decreasing mood over time (Pint=0.03). TTr did not affect mood. Independent of TTr decreasing WC over time improved mean EF (P=0.04) and SD scores (P=0.04), without CS effects. Increasing depression symptoms predicted a deterioration in EF (p=0.006).
TTr, visceral obesity, and mood have independent and interacting effects on EF and SD. Only TTr had CS benefits, which were greater in men with lower baseline EF and SD scores, and for SD greater in older men.