Role of Vitamin-D Receptor (VDR) single nucleotide polymorphisms in gestational hypertension development: A case-control study.

BACKGROUND Recent literature data have highlighted the important role of hypovitaminosis D in pregnancy complications and prenatal/perinatal health. Vitamin D action takes place through vitamin D receptor (VDR) activation. Two single nucleotide polymorphisms of VDR gene, FokI and BsmI, have been reported to affect VDR molecular signaling and be associated with several disorders, including hypertension. METHODS We carried out a case-control study aimed to assess vitamin D serum levels together with the distribution of VDR FokI and BsmI in a population of 116 pregnant women with gestational hypertension (GH) and 69 normotensive pregnant women (CTR). RESULTS Hypovitaminosis D was largely prevalent both in GH (81%) and CTR (69%) pregnant women. Vitamin D insufficiency (10-30 ng/ml) had a similar frequency in both cohorts (GH 60% vs CTR 58%), while vitamin D deficiency (<10 ng/ml) was more frequent in GH cohort than in CTR one (21% vs 11%). Regression analysis showed that GH was significantly (p = 0.031) linked to vitamin D status. Vitamin D deficiency was associated with a threefold-increased risk of developing GH, while a normal vitamin D status was protective against this pregnancy disorder. The VDR FF/bB haplotype was the most frequent in GH cohort, and resulted to increase by two folds the risk for GH. Notably, hypovitaminosis D was found in 92% of FF/bB GH pregnant women, 27% of which had deficient vitamin D levels compared with 11% of their normotensive counterparts. CONCLUSIONS Despite being preliminary, these findings suggest that genotyping of pregnant women for VDR polymorphisms may be useful for a tailored vitamin D supplementation strategy.