Variation in associations between allelic variants of the vitamin D receptor gene and onset of type 1 diabetes mellitus by ambient winter ultraviolet radiation levels: A meta-regression analysis

Abstract

Vitamin D receptor (VDR) gene polymorphisms may be associated with risk of developing type 1 diabetes mellitus (T1DM), but reports have been conflicting. The authors reexamined population-based case-control studies on selected VDR polymorphisms and T1DM to investigate whether variation in reported associations could be partly explained by differences in ambient winter ultraviolet radiation (UVR) levels. A meta-analysis of 16 studies from 19 regions (midwinter UVR range, 1.0-133.8 mW/m(2)) was conducted. The association between winter UVR and the log odds ratio was examined by meta-regression. For FokI and BsmI, the log odds ratio for the association between the F and B alleles and T1DM incre..