Association of Sex Hormone-Binding Globulin Gene Polymorphism and Sex Hormone-Binding Globulin Levels in Postmenopausal Women in Relation to Type 2 Diabetes Mellitus - A Case-Control Study

Background: In women, menopause constitutes the end of a fertile life as a result of ovarian aging. It is characterized by a significant decrease in estrogen concentration along with the change in the body weight, altered distribution of adipose tissue, less energy expenditure as well as modification in insulin secretion, and insulin sensitivity resulting in the development of type 2 diabetes mellitus (T2DM). The low circulating concentration of sex hormone-binding globulin (SHBG) contributes to the increased risk of type 2 diabetes in postmenopausal women. Methods: The present study was conducted at Justice K. S. Hegde Charitable Hospital, Deralakatte, Mangaluru. This case-control study was performed on 400 postmenopausal women with and without T2DM, aged 45-65 years, recruited based on the eligibility criteria. Five milliliters of fasting blood were collected, centrifuged, and stored at -80 degrees C until analysis. Genomic DNA was isolated from the whole blood using a standard protocol. DNA was amplified using the polymerase chain reaction. Amplified products were sequenced using the Sanger sequencing method. Statistical analyses were performed using the SPSS software version 26. Results: Based on the SHBG single-nucleotide polymorphisms (SNP) rs1799941, the circulating levels of SHBG showed a significant difference between the genotype. Conclusions: The major allele of rs1799941 has shown reduced the levels of circulating SHBG with an increased risk of T2DM. Hyperglycemia along its association with endogenous hormone and SNP in the SHBG gene may contribute to the diabetic risk in the postmenopausal women.