Vitamin D receptor gene polymorphisms and cardio-metabolic profile in women with hypovitaminosis D

Background: The possible role of vitamin D receptor (VDR) variants in determining cardiovascular risk factors has been suggested previously. The purpose of the present study was to evaluate the associations of variants of vitamin D receptor (VDR) gene with metabolic profile in Iranian overweight women with hypovitaminosis D. Methods: Variants in VDR gene including FokI (rs2228570), BsmI (rs1544410) and rs757343 were detected using PCR-sequencing. Metabolic Profile including fasting plasma glucose, total cholesterol, LDL-C, HDL-C, and triacylglycerol was assessed using commercial kits. Circulating 25 (OH) D was measured using ELISA kits. Fat mass and visceral fat were measured using Bio Impedance Analysis. Results: A sample of 123 overweight women with hypovitaminosis D (25 (OH) D<75nmol/L) was studied. The mean 25 (OH) D level was 28.7±17.0nmol/L. The FokI polymorphism was significantly associated with total cholesterol (p=0.03) and LDL-C (p=0.01). Carriers of the CC genotype of the FokI polymorphism had lower total cholesterol (162.9±30.4 vs. 176.1±32.4, p=0. 02) and LDL-C (98.0±26.0 vs. 110.6±28.5, p=0. 01) compared with carriers of CT+TT genotype. Regression analysis revealed that the FokI variant and fat mass explained 18% of the variance in total cholesterol. Regarding LDL-C, FokI variant explained 21% of the variance in LDL-C. None of the studied polymorphisms were significantly associated with adiposity phenotypes (p>0.05). Also, adiposity phenotype measures were not significantly different in the genotype groups of the studied SNPs (p>0.5). Conclusion: The present results indicate that the FokI polymorphism is significantly associated with total cholesterol and LDL-C in Iranian overweight women with hypovitaminosis D.