Variants of the adiponectin gene and type 2 diabetes in a Polish population

Several association studies of type 2 diabetes mellitus (T2DM) and adiponectin gene polymorphisms have been reported with conflicting results. Our aim was to search for the association of three polymorphisms (-11.391G>A, +45T>G, and +276G>T) in the adiponectin gene with T2DM and prediabetic quantitative traits in Polish Caucasians. The study groups comprised 495 unrelated T2DM cases and 435 controls. We compared the distribution of genotypes between study groups. In addition, genotype-quantitative trait analyses were also done in the controls. The study subjects were genotyped using the restriction fragment length polymorphism technique. The frequencies of the minor alleles were as follows: 10.6 versus 8.2% for -11.391G>A (p = 0.0722), 7.0 versus 8.0% for +45T>G (p = 0.48), and 15.5% in T2DM versus 19.8% in controls (p = 0.0145) for +276G>T, respectively. The difference for genotype distribution between the groups was statistically significant (p = 0.0247) for the +276G>T variant: 71.31 versus 62.99%, 26.46 versus 34.48% and 2.22 versus 2.53%, respectively, for GG, GT and TT. In quantitative traits analysis, the T allele of +276G>T was associated (p < 0.05) with lower insulin resistance (HOMA-IR, fasting insulin) among controls. Additionally, the A allele at position -11.391 was associated (p < 0.05) with higher insulin resistance (HOMA-IR, fasting insulin). In multiple regression analysis, all identified association remained significant after the inclusion in the model of gender, BMI and age. In addition, in this model, -11.391G>A and +276G>T were independently associated with T2DM. Finally, we conclude that the adiponectin gene polymorphisms are associated with T2DM and prediabetic quantitative traits in Polish Caucasians.