Serum sex hormone-binding globulin is associated with symptomatic late-onset hypogonadism in aging rural males: a community-based study

Background To investigate whether serum levels of sex hormone-binding globulin (SHBG) and testosterone are associated with symptomatic late-onset hypogonadism (SLOH) in middle-aged and elderly rural Chinese males.A population-based cross-sectional study was conducted in Zhejiang rural communities. A total of 965 men (aged 40-80 years) were admitted to the aging males' symptoms (AMS) scale and related physical examinations including body mass index (BMI) and waist circumference were conducted. Serum total testosterone (TT), free testosterone (FT), sex hormone-binding globulin (SHBG) and serum lipid levels were measured separately. Serum level of bioavailable testosterone (Bio-T) was calculated.A total of 965 participants were divided into two groups, symptomatic late-onset hypogonadism (SLOH) group (n = 202) (AMS score ≥27) and control group (n = 763), according to total AMS score. Men in the SLOH group were older (61.57±9.06 vs 54.95±8.27 years) and had a smaller waist circumference (81.06±6.89 vs 82.54±6.60 cm) than those in the control group. Moreover, a relatively higher level of SHBG and lower levels of FT, Bio-T, triglyceride (TG) and total cholesterol (T-CHOL) were found in the SLOH group compared with that in the control group (P < 0.05). Receiver operating characteristic curves (ROC) analysis showed that age (AUC = 0.702, P < 0.001) and SHBG (AUC = 0.617, P < 0.001) were potential predictive indicators for SLOH diagnosis, with the best cut-off values of 59 years for age and 44.40 nmol/L for SHBG.SHBG might be a potential predictor in men with hypogonadism, whereas BMI had no proportionality to the measurement of AMS. Age and SHBG should be used for SLOH diagnosis.