High levels of free and bioavailable testosterone independently predict a decreased risk of erectile dysfunction (ED) in younger men, according to new findings published online in the Journal of Sexual Medicine.
In a population-based prospective cohort study of 733 Chinese men followed for 4 years, investigators found that high free testosterone (FT) and bioavailable testosterone (BT) levels were associated with a significant 19% and 22% decreased risk of ED, respectively, in men aged 21–40 years in a fully adjusted model that accounted for age, body mass index, cigarette smoking, alcohol intake, physical activity, hypertension, diabetes, and sex hormone-binding globulin (SHBG). Total testosterone (TT) was not associated with ED risk in these men. Among men aged 41–65 years, TT, FT, and BT were not significantly associated with ED in either adjusted or unadjusted analyses.
The study, by Yawen Luo, BSc, and Haiying Zhang, MD, PhD, both of Guangxi Medical University in Nanning, Guangxi, China, and colleagues, demonstrated that men with both low FT and high SHBG had the highest ED risk. Their risk was a significant 4.6 times higher compared with men who had high FT and low SHBG (reference), the researchers reported.