Impacts of low-grade inflammation on the correlation of serum testosterone and carotid intima-media thickness in type 2 diabetes mellitus men

Objective To investigate the impacts of low-grade inflammation on the correlation of serum testosterone (T) and carotid intima-media thickness (CIMT) in type 2 diabetes mellitus (T2DM) men. Methods Based on the concentration of C-reactive protein (CRP) and T, a total of 247 patients was divided into low-grade inflammation with low T group ( LI-LT, CRP ≥ 2.0 mg/L, T < 12.0 nmol/L, n=65), low-grade inflammation with normal T group (LI-NT, n=67), non-low-grade inflammation with low T group (NLI-LT, n=56), and non-low-grade inflammation with normal T group (NLI-NT, n=59). General information, medical history, and anthropometry data were collected. Glycosylated hemoglobin A1c (HbA1c), blood fat, and CIMT were detected. Results Compared to NLI-NT group, CIMT in NLI-LT group was increased without statistical significance [(0.87±0.09) vs (0.90±0.10)mm, t=1.693, P=0.090]. CIMT in LI-LT group was increased significantly compared to that of LI-NT group [(0.99±0.10) vs (1.07±0.12)mm, t=5.208, P=0.000]. Correlation analysis indicated that serum T correlated negatively with CIMT (n=247, r=-0.368, P<0.01) in whole. The correlation coefficient of T and CIMT was -0.582 (P=0.000), and -0.098 (P=0.087) in patients with (n=132) and without (n=115) low-grade inflammation, respectively. To make CIMT dependent coefficient and serum T independent coefficient in multiple regression analysis, the partial regression coefficient was -0.062(95% CI: -0.094~-0.029, P=0.008), and -0.045 (95% CI: -0.087~-0.002, P=0.036), respectively, before and after the adjustment of age, smoking, family history, T2DM course, body mass, blood pressure, HbA1c, and blood fat. After the additional adjustment of CRP, the partial regression coefficient was -0.019(95% CI: -0.120~0.042, P=0.287). Conclusions The negative relationship between serum T and CIMT in T2DM men might be modulated by low-grade inflammation. Key words: Inflammation; Diabetes mellitus, type 2; Testosterone/blood; Carotid arteries/pathology