Objective: To investigate the effect of the interaction between methylenetetrahydrofolate reductase(MTHFR) genotype and allele and long-term exposure to organophosphorus pesticides on the development of type 2 diabetes mellitus(T2 DM).
Methods: A total of 209 cases of T2 DM(case group) and 216 cases without T2 DM(control group) were selected as subjects. The polymorphism of MTHFR(rs1801133) was detected by TaqMan probe technique. The relationship between genes, long-term exposure to organophosphorus pesticides and T2 DM was analyzed by Logistic regression. The interaction between gene and long-term exposure to organophosphorus pesticides was discussed by crossover analysis and generalized multifactor dimensionality reduction.
Results: BMI⇿4, residence in countryside, long-term exposure to organophosphorus pesticides and family history of diabetes mellitus were risk factors for T2 DM. MTHFR genotype distribution conformed to Hardy-Weinberg equilibrium(P>0. 05). There was no significant difference in genotype distribution frequency between case group and control group. The risk of T2 DM in individuals with CT and TT genotypes was 1. 667 times higher than that of CC genotypes after adjusting the covariates at rs1801133 locus in the dominant model(95%CI 1. 057-2. 627, P=0. 028). It suggested that the samples of allele T had a increased risk of T2 DM compared with those without allele T. The above models still had statistical significance(P<0. 05) after adjusting the covariates. Forth, crossover analysis showed that the gene MTHFR(rs1801133) and long-term exposure to organophosphorus pesticides had multiplication interaction. The interaction between gene MTHFR(rs1801133) and long-term exposure to organophosphorus pesticides may play a role in the pathogenesis of T2 DM. Generalized multifactor dimensionality reduction(GMDR)analysis showed that the interaction model of MTHFR(rs1801133) gene and family history of diabetes mellitus was the best model.
Conclusion: MTHFR(rs1801133) gene CT and TT genotype may be risk factors for T2 DM. The interaction between genetic polymorphism and environmental factors increases the risk of T2 DM.
Keywords: interaction effect; methylenetetrahydrofolate reductase; organophosphorus pesticides; polymorphism; type 2 diabetes mellitus.