Sex hormone binding globulin gene polymorphisms and metabolic syndrome in postmenopausal Turkish women

Background: Insulin resistance is associated with obesity, glucose intolerance or diabetes, hypertension, dyslipidemia, and cardiovascular disease. Constellation of these risk factors is called metabolic syndrome (MetS). MetS is common among postmenopausal women. Low sex hormone binding globulin (SHBG) levels associate with an increased risk of MetS in postmenopausal women. Variations in SHBG gene associate with low levels of circulating SHBG levels. We aim to study the association between SHBG gene polymorphisms - rs1799941 (A/G) and rs6257 (T/C) - with MetS among postmenopausal women. Methods: The study population consisted of 182 postmenopausal women with MetS and 119 control subjects. We analyzed the allele frequencies of SHBG gene polymorphisms in relation to the risk components of MetS. Results: MetS patients displayed significantly lower SHBG levels compared to the lean control subjects (p = 0.036). rs1799941 A allele was associated with high SHBG levels (p = 0.031), low blood pressure, body mass index and waist circumference. The number of 'high risk' alleles (G allele of the rs1799941 and T allele of rs6257) correlated positively with waist circumference (r = 0.203, p = 0.006) and negatively with SHBG levels (r = - 0.291, p = 0.024). Conclusions: SHBG gene polymorphisms associate with SHBG levels and MetS risk components among postmenopausal women. Hence, A allele (rs1799941) may have a protective effect for MetS through its association with high SHBG levels among postmenopausal women.