The Association between Inflammation, Testosterone and SHBG in men: A cross-sectional Multi-Ethnic Study of Atherosclerosis

Context: Earlier studies have investigated the role of obesity-related inflammation and endogenous sex hormones in men. The role of interleukin-6 (IL-6) and C-reactive protein (CRP) with testosterone and sex hormone binding globulin (SHBG) levels in men is still debated.

Objective: To investigate the independent association between levels of high sensitivity CRP (hsCRP) and IL-6 with endogenous sex hormones in men.

Design: Cross-sectional observational study using data from the Multi-Ethnic Study of Atherosclerosis.

Patients or other participants: A community-based sample of 3212 men aged 45-84 years was included. After exclusions, 3041 men remained for the analyses.

Main outcome measure(s): Serum concentrations of testosterone, SHBG, hsCRP, IL-6, and sTNFR were measured from the baseline exam. Multivariable linear regressions were used to examine the association of inflammatory markers with sex hormones.

Results: An inverse association was found between levels of hsCRP and levels of testosterone and SHBG, even after adjustment for confounders and IL-6 (Total Testosterone; B = -0.14, Bioavailable Testosterone; B = -0.06, and SHBG; B = -0.66). Similar results were found for IL-6, although a positive association was found for SHBG (B = 0.95). Notably, an inverse association was found for IL-6 with bioavailable testosterone in African Americans and Hispanic Americans aged 45-54 years. No associations were found for sTNFR and endogenous sex hormones.

Conclusion: Our results indicate that inflammatory markers have independent associations with levels of testosterone (total and bioavailable) and furthermore, appear to associate differently with SHBG levels.