Inverse association of testosterone and the metabolic syndrome in men is consistent across race and ethnic groups

Context: Low sex hormone levels have been associated with the metabolic syndrome (MetS). Objectives: Our objective was to determine whether the association between sex hormone levels and MetS varies by race/ethnicity among men and to investigate the relationship of sex hormones and individual components of MetS. Design: We conducted a population-based observational survey. Participants: A multistage stratified design was used to recruit a random sample of 2301 racially/ethnically diverse men age 30-79 yr. Blood samples were obtained on 1899 men. Analyses were conducted on 1885 men with complete data on total testosterone ( T), free T, and SHBG. Interventions: There were no interventions. Main Outcome Measure: MetS was defined using a modification of the Adult Treatment Panel III guidelines. The association between MetS and sex hormone levels was assessed using odds ratios and 95% confidence intervals estimated using logistic regression models. Results: A strong inverse association was observed, in both bivariate and multivariate analyses, between hormone levels and MetS. The odds of MetS increased about two-fold with a 1 SD decrease in hormone levels. The association between sex hormones and MetS was statistically significant across racial/ethnic groups. Although the magnitude of this association was largest among White men, racial/ethnic differences were not statistically significant. The strength of the association of sex hormones with individual components of MetS varied; stronger associations were observed with waist circumference and dyslipidemia and more modest associations with diabetes and elevated blood sugar. Conclusions: A robust, dose-response relationship between sex hormone levels and odds of the metabolic syndrome in men is consistent across racial/ethnic groups.