Supplementary Material



Background: The purpose of this study was to perform a systematic review and meta-analysis evaluating the potential relationship between BsmI vitamin D receptor (VDR) polymorphismand hip fractures as a practical, useful disease prediction method.

Methods: The assessment of eligibility of the selected studies was performed based on the following criteria: a) studies showing an analysis of the association between a genetic variant in BsmI and hip fractures; b) case-control design study or cohort study; c) data enabling the counting of genotypes/alleles to calculate risk estimates; d) studies providing definite information on the source of controls and patients with hip fractures, diagnostic methods and protocols, genotyping and statistical analysis, and e) studies written in English.

Results: The genetic variant BsmI was not associated with overall hip fractures except in one model. In age-based subgroup meta-analysis (age over 75 or under 75 years), statistically significant associations were observed in the age over 75 years subgroup for the same genetic models as in the overall data synthesis. However, the over-dominant model did not show any significant difference.

Conclusions: BsmI VDR polymorphism conferred an increased risk of hip fracture in people over 75 years old. It was supposed that people, specifically very old aged people, with functional defects in VDR experience more rapid decreases in bone mineral density than those with normally functional VDR. These results indicate that BsmI VDR polymorphisms might be a predictor of hip fractures in older people.