Association of vitamin D receptor gene polymorphisms, metabolic features and susceptibility to polycystic ovary syndrome: a preliminary study

Abstract

Research question

Are the combined genotypes and haplotypes of vitamin D receptor (VDR) gene polymorphisms (FokI, ApaI and TaqI) associated with susceptibility to polycystic ovary syndrome (PCOS) and metabolic features of the disease?

Design

This case–control study included 46 women with PCOS and 48 controls. Genotypes of the VDR gene were determined using the polymerase chain reaction–restriction fragment length polymorphism method. Waist circumference, and parameters of lipid and glucose metabolism were evaluated in all women.

Results

Women in the PCOS group had a larger waist circumference (P = 0.0383) and a higher visceral adiposity index (VAI) (P < 0.0001) compared with controls. Total cholesterol (P < 0.0001), high-density lipoprotein cholesterol (P = 0.00001) and triglyceride (P < 0.0001) concentrations were higher in the PCOS group. The VDR-FokI C/C (F/F) genotype was associated with significantly higher odds of PCOS (adjusted OR 6.27, 95% CI 1.53–25.65). The VDR-ApaI genotype was associated with susceptibility to PCOS in the dominant model; the variant genotypes [A/C + A/A (A/a + a/a)] had higher odds of PCOS than the wild genotype [C/C (A/A)] (adjusted OR 3.15, 95% CI 1.07–9.32). Haplotype analysis revealed that the T-C-T (f-A-T) haplotype was significantly associated with lower odds of PCOS (adjusted OR 0.10, 95% CI 0.01–0.95). Women with PCOS carrying the VDR-FokI T/T (f/f) genotype had lower fasting glucose (P = 0.0469) and higher VAI (P = 0.0406) compared with women with the C/T (Ff) + C/C (F/F) genotype.

Conclusion

The present findings suggest an association between FokI and ApaI polymorphisms and PCOS susceptibility. Moreover, the VDR-FokI T/T (f/f) genotype could be a marker for decreased fasting glucose in women with PCOS. No association was found between the TaqI polymorphism and PCOS susceptibility in the study population.