The genetic polymorphisms in vitamin D receptor and the risk of type 2 diabetes mellitus: an updated meta-analysis.

Vitamin D receptor (VDR) genetic polymorphisms are considered to be associated with type 2 diabetes mellitus (T2DM), but this is inconclusive. The aim of this study is to quantify the association between polymorphisms of BsmI and FokI in the VDR gene and T2DM risk through literature review.Original articles published from 1999 to June 2014 were discovered through PubMed, ISI Web of Science, China National Knowledge Infrastructure, Chinese Wanfang Database, and the Chinese Biomedical Literature Database. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated with software STATA version 12.0.Twenty-three articles containing 30 case-control studies were included. The association between the BsmI polymorphism and T2DM was weak in two genetic models (Bb vs bb and BB+Bb vs bb). The subgroup analysis showed that this association was only found in the studies with a small sample size (<200). A strong association between FokI polymorphism and T2DM indicated that this gene polymorphism was possibly a risk factor for T2DM (ff vs FF: OR=1.57, 95% CI: 1.28-1.93, p<0.001; Ff vs FF: OR=1.54, 95% CI: 1.31-1.81, p<0.001; ff+Ff vs FF: OR=1.57, 95% CI: 1.35-1.83, p<0.001), especially in Chinese populations.More reliable conclusions about associations between VDR genetic polymorphisms and T2DM will depend on studies with larger sample size and by ethnicity.背景与目的： 研究发现维生素D受体（VDR）基因多态性与2 型糖尿病 （T2DM）的发病关系密切，但相关文献报道结论并不一致。本研究的目的是 通过文献系统综述对VDR受体基因BsmI和FokI位点单核苷酸多态性与T2DM的 关联性进行评价。方法与研究设计：于PubMed 、ISI Web of Science、中国期 刊全文数据库（CNKI） 、中国万方数据库和中国生物医学文献数据库 （CBM）中检索1999年至2014年期间发表的所有相关文献。运用Stata 12.0软 件，通过计算OR值和95% CI来评价位点BsmI和FokI变异与T2DM的关联性。 结果：共23篇文献30个病例对照研究纳入本次meta分析中。分析结果显示 BsmI位点单核苷酸多态性与T2DM易患性在两种基因模型中（Bb vs bb 和 BB+Bb vs bb）存在弱的相关性。亚组分析显示这种弱的相关性主要出现在样 本量较小的研究中（<200）。FokI位点单核苷酸多态性与T2DM易患性（ff vs FF：OR=1.57，95% CI：1.28-1.93，p<0.001; Ff vs FF：OR=1.54，95% CI： 1.31-1.81，p<0.001; ff+Ff vs FF：OR=1.57，95% CI：1.35-1.83，p<0.001）存 在强的相关性，提示该位点基因突变是T2DM的危险因素，尤其是在中国汉族 人群中。结论：有关VDR基因与T2DM的关联分析还需要大样本量和不同种族 研究的支持。.