Background:Polymorphisms of microRNA (miRNA),as a novel mechanism,are closely associated with disease states by interfering with miRNA function.Direct correlations have been identified between single-nucleotide polymorphisms (SNPs) in miRNA,but the effect on type 2 diabetes mellitus (T2DM) onset among Chinese population remains unclear.Therefore,the aim of this study was to identify correlations between common SNPs in miR-27a,miR-146a,and miR-124a with T2DM among a Chinese population,as well as to explore diabetic pathological mechanisms and the impact of environmental factors.Methods:SNPscan technology was used to genotype 995 patients newly diagnosed with T2DM and 967 controls.Logistic regression analysis was performed to compare mutation frequencies between cases and controls.Results:We found no significant correlations between all genotypes of these miRNAs and T2DM in our research.However,stratification analysis identified a lower risk of T2DM associated with the rs531564GC genotype among younger subjects (age ＜ 45 years) (adjusted P =0.043; odds ratio [OR] =0.73; 95％ confidence interval [CI] =0.54-0.99).Furthermore,the rs895819CC genotype in overweight people (24 ＜ body mass index [BMI] ＜ 28) was significantly associated with an increased risk of T2DM (adjusted P =0.042; OR =1.73; 95％ CI =1.02-2.94),while the rs2910164 genotype in miR-146a was not significantly correlated with T2DM.The genetic risk score was calculated based on the number of risk alleles of the three SNPs and was found to be correlated to total cholesterol (adjusted P =0.021).Conclusions:The rs531564GC genotype acted as a protective factor to decrease the risk of T2DM in younger subjects (age ＜ 45 years),while the presence of the rs895819CC genotype increased the risk of illness among overweight subjects (24 ＜ BMI ＜ 28 kg/m2).The presence of SNPs in miRNA might promote disease by affecting miRNA expression and gene function.Thus,miRNA mimics or inhibitors that directly regulate miRNA expression present novel and promising therapeutic targets.