Single Nucleotide Polymorphisms in Vitamin D Receptor Gene Affect Birth Weight and the Risk of Preterm Birth: Results From the "Mamma & Bambino" Cohort and A Meta-Analysis

The effect of vitamin D receptor gene (VDR) polymorphisms on adverse pregnancy outcomesincluding preterm birth (PTB), low birth weight and small for gestational ageis currently under debate. We investigated 187 mother-child pairs from the Italian Mamma & Bambino cohort to evaluate the association of maternal VDR polymorphismsBsmI, ApaI, FokI and TaqIwith neonatal anthropometric measures and the risk of PTB. To corroborate our results, we conducted a meta-analysis of observational studies. For the FokI polymorphism, we showed that gestational duration and birth weight decreased with increasing number of A allele (p = 0.040 and p = 0.010, respectively). Compared to the GG and GA genotypes, mothers who carried the AA genotype exhibited higher PTB risk (OR = 12.049; 95% CI = 2.606-55.709; p = 0.001) after adjusting for covariates. The meta-analysis confirmed this association under the recessive model (OR = 3.67, 95%CI 1.18-11.43), and also pointed out the protective effect of BsmI polymorphism against the risk of PTB under the allelic (A vs. G: OR = 0.74; 95%CI 0.59-0.93) and recessive (AA vs. GG + AG: OR = 0.62; 95%CI 0.43-0.89) models. Our results suggest the association between some maternal VDR polymorphisms with neonatal anthropometric measures and the risk of PTB.