The Relationship Of Sex Hormone Binding Globulin (SHBG) Gene Polymorphisms With Serum SHBG Level And Metabolic Syndrome In Chinese Han Males

Part One The relationship between sex hormone-binding globulin and metabolic syndrome in pre-elderly and elderly men in China[Objective] The purpose of this study was to examine the relationship between SHBG and the Metabolic Syndrome (MetS) in pre-elderly and elderly men in China.[Methods] A cross-sectional study was done among437men, aged45to94. Early morning fasting sera were assayed for total testosterone (TT), SHBG and other biochemical markers. Free testosterone (FT) was calculated.[Results] The SHBG level of the MetS group was significantly lower than those without MetS(35.70(21.93)nmol/L vs41.90(23.40)nmol/L; p<0.001). As the number of MetS components increases, SHBG and TT levels became lower. SHBG correlated with age, TT and most of metabolic components. Body mass index (BMI), high density lipoprotein-Cholesterol (HDL-C), triglyceride (TG) and TT remained independently associated with SHBG in the multivariate regression analysis. In a logistic regression taking MetS as the dependent variable, SHBG (95%CI:0.975伍0.994, P=0.018) and homeostasis model assessment for insulin resistance (HOMA-IR)(95%CI:1.535伍2.647, P<0.001) were included in the final model. SHBG and homeostasis model assessment for insulin resistance (HOMA-IR) were included in the final model.[Conclusions] Lower SHBG is independently associated with MetS among pre-elderly and elderly men. SHBG may be an independent predictor of MetS, but the mechanism of how SHBG is involved in MetS needs to be further studied. Part two The relationship of sex hormone binding globulin (SHBG) gene polymorphisms with serum SHBG level and metabolic syndrome in pre-elderly and elderly men in China[Background] Epidemiological studies have shown that circulating sex hormone binding globulin (SHBG) levels are associated with metabolic disorders, and are lower in metabolic syndrome (MetS) patients than in non-MetS individuals. In this study, we investigated the relationship of polymorphisms in the SHBG gene with serum SHBG levels and the presence of MetS in Han Chinese males.[Methods] We performed a cross-sectional study of316subjects who were recruited from a health checkup population at Zhongshan Hospital, Fudan University. Anthropometric measurements, blood pressure, fasting plasma glucose, lipid levels, total testosterone, and SHBG were determined, in addition to the seven SHBG single nucleotide polymorphisms (SNPs).[Results] The variant allele (AG or AA) carriers in rs6259was associated with a lower risk for MetS compared to the wild-type allele carriers (GG)(OR=0.56,95%confidence interval [CI]=0.33to0.96]). For the CT or TT allele carriers compared to CC allele carriers in rs3760213, the OR for MetS was0.59(95%CI=0.34to1.00). The rs6259variant allele (AG or AA) carriers had higher serum SHBG and TT than the wild-type carriers (GG)(P=0.016, P=0.004). For rs3760213, SHBG and TT levels were higher in the variant allele carriers (CT or TT) than the wild-type carriers (CC)(P=0.029, P=0.009). Carriers having both of the variant alleles had the lowest risk of MetS (OR=0.51,95%CI=0.275to0.950) and the highest SHBG levels. The risk of MetS rose with the decreasing of serum SHBG levels in rs6259and rs376021carriers.[Conclusions] Rs6259and rs3760213SNPs are associated with the risk of MetS and serum SHBG level in Chinese Han males.