Background: Concentrations of adiponectin, the protein product of the adipocyte C1q and collagen-domain-containing (ADIPOQ) gene are associated with type 2 diabetes and coronary artery disease. We investigate the association of single-nucleotide polymorphisms (SNPs) in the ADIPOQ gene with adiponectin concentrations, and to parameters of metabolic syndrome.
Methods: 867 unrelated, non-diabetic Korean women, 20 to 69 y, were genotyped for 8 SNPs in the ADIPOQ gene (-11391G>A, -11377C>G, H241P, Y111H, G90S, R221S, 45T>G, 276G>T). Adiponectin, a homeostasis model assessment of insulin resistance (HOMA-IR), and metabolic parameters were measured.
Results: Carriers of genotype T/T at position 276 had significantly higher adiponectin concentrations than G/G carriers (P=0.005). Homozygous carriers of the TG haplotype (i.e., individuals who were T/T at 45 and G/G at 276) and heterozygous carriers of the TG haplotype (TG/X) had lower adiponectin concentrations than non-TG carriers (P<0.001). Significant associations between SNP at 276 and serum concentrations of triglyceride (P=0.013), insulin (P=0.013) and HOMA-IR (P=0.012) were found. The 45-276 haplotypes had associations identical to the 276G>T SNP. In subgroup analysis, subjects carrying the TG haplotype had significantly lower adiponectin concentrations than non-TG carriers in both normal weight (P<0.001) and overweight-obese (P=0.009) subgroups. The association of the TG haplotype with increasing insulin concentrations was significant among overweight-obese subjects (P=0.004), but was not significant among normal weight subjects. A similar association was found between the 45-276 haplotype and HOMA-IR.
Conclusion: There is a strong association of the adiponectin SNP276 genotypes and the adiponectin 45-276 haplotypes with circulating adiponectin concentrations in non-diabetic Korean women. In addition, this haplotype is associated with increased insulin concentrations and insulin resistance index only in overweight-obese individuals.