Cross-sectional association of metabolic syndrome and its components with serum testosterone levels in a Korean-screened population

Purpose: We evaluated the associations of metabolic syndrome (MetS) and its components with testosterone levels in the Korean population. Materials and Methods: This cross-sectional study was performed among 6,967 adult (age≥20 years) men who attended health screening during 2006 to 2015. MetS was defined using the National Cholesterol Education Program Adult Treatment Panel III criteria. Associations were evaluated using unconditional logistic regression. Results: The estimated age-adjusted prevalence of MetS in adult and middle-aged (≥40 years) Korean men was 27.5% and 30.6%, respectively. Quartile analysis showed that high serum testosterone levels were significantly associated with a low risk of MetS (highest vs. lowest quartile, odds ratio=0.528; p_trend<0.001), with an approximately 13% reduction in MetS risk per 1 ng/mL increment of serum testosterone levels. After considering covariates such as age and body mass index (BMI), the reduction in MetS risk was attenuated but remained significant (7% reduced risk per 1 ng/mL). Testosterone levels were inversely correlated with all MetS components, including hyperglycemia (r=-0.041), increased body size (r=-0.093), increased triglyceride levels (r=-0.090), decreased high-density lipoprotein cholesterol levels (r=-0.030), and elevated blood pressure (r=-0.071, all p<0.05). Among them, elevated triglyceride levels and blood pressure were independently associated with low serum testosterone levels, even after adjustment for age and BMI. Conclusions: Serum testosterone levels were inversely associated with MetS in Korean men. This association was attenuated after adjustment for age and BMI but remained significant. Among MetS components, increased triglyceride levels and elevated blood pressure were independently associated with testosterone levels, regardless of obesity.