Vitamin D Receptor Polymorphisms Associated with Susceptibility to Obesity: A Meta-Analysis

BACKGROUND: Obesity has become a global public health problem. Obesity increases the risk of several lethal diseases. This study aimed to assess whether the obesity susceptibility was associated with genetic variation in vitamin D receptor (VDR) gene by conducting a meta-analysis. MATERIAL/METHODS: PubMed, EMBASE and Cochrane Library databases were screened for all relevant articles published up to October 2018. The pooled odds ratios (OR) were calculated using STATA 13.0 software for 4 polymorphisms in the VDR gene (ApaI, BsmI, FokI and TaqI). RESULTS: Seven case-control studies, including 1188 obese patients and 1657 healthy controls, were recruited. The pooled findings showed that there were no associations between obesity risk and the VDR polymorphisms in ApaI, BsmI and TaqI loci overall. However, VDR TaqI polymorphism was associated with the risk of obesity in Asian under homozygous [TT versus tt: odds ratio (OR)=0.26, 95% confidence interval (CI)=0.14–0.49; P<0.001], heterozygous (Tt versus tt: OR=0.34, 95% CI=0.18–0.64; P=0.001), and dominant (TT+Tt versus tt: OR=0.30, 95% CI=0.17–0.52; P<0.001) models; FokI variant was related with increased risk of obesity only under dominant model (FF+Ff versus ff: OR=1.54, 95% CI=1.15–2.06; P=0.004). CONCLUSIONS: Our meta-analysis results suggest that the T allele of TaqI may have a protective effect, while the F allele of FokI is proposed as a risk factor related to obesity.