Polymorphism in the transcription factor 7-like 2 (TCF7L2) gene is associated with impaired proinsulin conversion—A meta-analysis

Abstract Aims Available evide nce supports the emerging hypothesis that the T-Allele of the transcription factor 7-like 2 ( TCF7L2 ) rs7903146 may be associated with the risk of impaired proinsulin conversion, but no consensus was available up to now. Methods A computer-based search of electronic databases (PubMed, EMBASE, Cochrane Library) and reference lists of relevant articles was carried out, and then 19 studies involving 15830 subjects were identified. The combined weighted mean difference (WMD) and their corresponding 95% confidence interval (CI) were calculated by a fixed or random effect. Results In the overall analysis, the T-Allele was observed to be significantly associated with the risk of impaired proinsulin conversion (up-regulate fasting proinsulin concentration WMD −0.40pM/L (95% CI −0.57 to −0.23); down-regulate fasting insulin concentration 3.86pM/L (95% CI 1.91 to 5.81)). Subgroup analyse stratified by subjects population characteristics and ethnicity were performed. The results indicated the TCF7L2 rs7903146 polymorphism was associated with the risk of impaired proinsulin conversion in various population characteristics study. With only a few of subjects in Asians and Africans were available, we failed to detect significant ethnic difference about TCF7L2 rs7903146 polymorphism and the risk of impaired proinsulin conversion. Conclusions Our results indicated that the T-Allele of the TCF7L2 rs7903146 is a significantly risk factor for impaired proinsulin conversion. Future research should gather more data about the effect of TCF7L2 rs7903146 polymorphism on Asians and Africans.