Metabolic burden is independently and linearly associated with lower testosterone levels: evidence from NHANES
Yavuz GülerAbstract
Objectives
Testosterone deficiency and metabolic dysfunction frequently coexist in aging men; however, whether metabolic impairment is associated with a progressive decline in testosterone across the metabolic spectrum remains unclear.
Methods
We analyzed 2,192 U.S. men aged ≥40 years from the National Health and Nutrition Examination Survey (NHANES). Metabolic burden was assessed using the triglyceride–glucose (TyG) index. Survey-weighted linear regression models were used to evaluate the association between TyG and log-transformed total testosterone after adjustment for age, HDL cholesterol, diabetes, and smoking. Dose–response relationships were further examined using quartiles and restricted cubic spline analyses.
Results
Higher TyG levels were independently associated with lower testosterone concentrations. In fully adjusted models, each 1-unit increase in TyG was associated with an approximately 12 % decrease in testosterone (p<0.001). Compared with the lowest TyG quartile, men in the highest quartile had approximately 19 % lower testosterone levels. Spline analysis demonstrated a consistent inverse association without significant nonlinearity (p for nonlinearity=0.21), supporting a graded and continuous relationship across the metabolic spectrum.
Conclusions
Higher metabolic burden was independently associated with lower total testosterone levels in middle-aged and older men. However, due to the cross-sectional design and absence of SHBG/free testosterone measurements, these findings should be interpreted cautiously and require confirmation in longitudinal studies.