BsmI, TaqI, ApaI and Fold polymorphisms in the vitamin D receptor (VDR) gene and sisk of fracture in Caucasians: A meta-analysis

Context: Vitamin D receptor (VDR) gene polymorphisms have been strongly associated with bone mineral density in some studies. However, in a recent meta-analysis, no relationship of the VDR Bsml or Taql polymorphism and fracture risk was found in the meta-analysis of published data. Objective and design: Our meta-analysis studied whether a relationship exists between Bsml, Taql, Apal and Fokl polymorphisms in the VDR gene and risk of fracture. Data sources: Relevant studies were identified from the following electronic databases: MEDLINE, EMBASE and Current Contents before January 2010. Data synthesis: This meta-analysis included 17 studies with a total of 21 eligible comparisons, which included 2112 fracture cases and 4521 controls. All of these studies reported on Caucasians. The combined results based on all studies showed that fracture cases had a significantly lower frequency of bb genotype of Bsml [odds ratio (OR) = 0.87, 95% confidence interval (Cl) = 0.76, 0.98]. When stratifying by fracture type, we found that (1) hip fracture cases had a significantly lower frequency of bb genotype of Bsinl (OR = 0.82, 95% Cl =0.70, 0.97); (2) hip fracture cases had a significantly lower frequency of Tt genotype of Taql (OR = 0.65, 95% Cl = 0.43, 0.97): (3) hip fracture cases had a significantly higher frequency of tt genotype of Taql (OR= 1.74, 95% Cl = 1.05, 2.91): (4) vertebral fracture cases had a significantly higher frequency of Aa genotype of Apal (OR= 1.63, 95% CI = 1.03, 2.59). No significant difference was found in any genotype of Fold. Conclusion: Our meta-analysis suggests that there is a modest but statistically significant association between the Bsml bb genotypes and fracture. (C) 2010 Elsevier Inc. All rights reserved.