ENPP1 K121Q polymorphism and type 2 diabetes mellitus in the Chinese population: a meta-analysis including 11,855 subjects

Ectoenzyme nucleotide pyrophosphate phosphodiesterase 1 (ENPP1) K121Q gene polymorphism has been suggested to be associated with the increased risk of developing type 2 diabetes mellitus (T2D), but relevant research results are still contradictory. To explore the relationship between ENPP1 K121Q gene polymorphism and T2D in the Chinese population, a meta-analysis was performed. Fourteen independent studies involving 11 855 subjects were retrieved from electronic databases. The pooled odds ratio (ORs) for the distribution of Q allele frequency of the ENPP1 K121Q gene and its corresponding 95% confidence interval (95% CI) were assessed using a random-effects model. Under an allelic model of inheritance, the distribution of Q allele frequency was 0.107 for the T2D group and 0.093 for the control group. The pooled OR for the distribution of Q allele frequency of ENPP1 K121Q gene was 1.29 (95% CI, 1.09-1.53; P(heterogeneity) = .006; I(2) = 55.6%). There was a significant association between ENPP1 K121Q gene polymorphism and T2D in the Chinese population (P = .003). Under a dominant model of inheritance, the KQ + QQ/KK value was 0.259 for the T2D group and 0.220 for the control group. The pooled OR for the KQ + QQ/KK value was 1.51 (95% CI, 1.20-1.91; P(heterogeneity) < .0001; I(2) = 71.8%). The association between ENPP1 K121Q gene polymorphism and T2D in the Chinese population followed a dominant model of inheritance (P = .0005). In the Chinese population, the ENPP1 K121Q gene polymorphism was implied to be involved with T2D susceptibility. People with the Q allele of the ENPP1 K121Q gene might be predisposed to T2D.