Association of IL-6 C-174G (rs 1800795) single nucleotide polymorphism with type 2 diabetes mellitus in Pakistani population.

Objective: To determine the association of interleukin-6 C-174G single nucleotide polymorphism with type 2 diabetes mellitus and metabolic parameters.

Methods: This case-control study was conducted from June 2012 to December 2013 at the Military Hospital Rawalpindi, the Centre for Research in Experimental and Applied Medicine, Army Medical College, Rawalpindi, and the Institute of Biomedical and Genetic Engineering, Islamabad, Pakistan. Two cohorts of subjects were genotyped for the single nucleotide polymorphism. One cohort comprised type 2 diabetics and other included healthy subjects. In these groups, serum interleukin-6, serum insulin, blood sugar fasting, lipid profile, body mass index and insulin resistance was determined and correlated with genotypes.

Results: Of the 789 participants, 539(68.3%) were in the study group and 250(31.7%) in the control group. Serum interleukin-6 was significantly higher in diabetics than healthy controls (p<0.0001). The frequency of GG, GC and CC was 267(49.5%), 235(43.6%) and 37(6.9%) in diabetic patients and 128(51.2%), 74(29.6%) and 48(19.2%) in healthy controls, respectively. Interleukin-6 C-174G single nucleotide polymorphism was significantly associated with diabetes [odds ratio = 3.22 (95% confidence interval: 2.04-5.1; p<0.0001). Genotypes were within Hardy-Weinberg equilibrium. Interleukin-6 C-174G single nucleotide polymorphism was significantly associated with serum interleukin-6 in the order of GC>GG>CC but was not associated with body mass index, insulin resistance, serum insulin and dyslipidaemia in diabetic patients (p>0.05 each).

Conclusions: Interleukin-6 C-174G single nucleotide polymorphism was a risk factor in type 2 diabetes and contributed to higher serum interleukin-6 levels among the participants.