Age-Specific Associations Between the Testosterone-to-Estradiol Ratio and Metabolic Syndrome Components in Middle-Aged and Elderly Chinese Men

Abstract

Background Metabolic syndrome (MetS) is common in aging men, but the age-specific relationship between the testosterone-to-estradiol (T/E2) ratio and metabolic abnormalities remains insufficiently characterized. This study evaluated age-stratified associations between the T/E2 ratio and MetS-related parameters in middle-aged and elderly Chinese men. Methods This retrospective cross-sectional study included 120 Chinese men aged 46–75 years. Participants were divided into three age groups: 46–55, 56–65, and 66–75 years. Serum testosterone, estradiol, sex hormone-binding globulin (SHBG), anthropometric indices, blood pressure, fasting blood glucose, and lipid profiles were assessed. MetS components were defined according to IDF-based criteria, and TyG index and TyG-BMI were calculated. Age-stratified Pearson correlation analyses were performed, with Spearman correlation and FDR adjustment used for sensitivity analyses. Results The T/E2 ratio decreased significantly across age groups, while SHBG increased and T/SHBG decreased with age. In the 46–55-year group, the T/E2 ratio was inversely correlated with fasting blood glucose, waist circumference, TyG-BMI, and total MetS points score. In the 66–75-year group, the main inverse association was observed between the T/E2 ratio and triglycerides. No consistent significant associations were observed in the 56–65-year group. Sensitivity analyses showed generally consistent directions for the main associations. Conclusions The T/E2 ratio shows age-related decline and age-specific associations with selected MetS-related parameters in middle-aged and elderly Chinese men. These findings suggest that the T/E2 ratio may reflect age-related metabolic heterogeneity, but prospective studies are needed to clarify its longitudinal and clinical relevance.