Association of -174 G>C interleukin-6 gene polymorphism with interleukin-6 and c-reactive protein levels and obesity: A case-control study among people/residents of Western Indonesia

Abstract

Background: Interleukin-6 (IL-6) and C-Reactive Protein (CRP) are mediators of inflammatory responses and increase in people who are obese . The increase of IL-6 and CRP levels is modified by polymorphism of -174 G>C IL-6 gene.

Aim: The purpose of this study was to investigate the relationship between -174 G>C IL-6 polymorphism gene on the level of IL-6 and CRP in the population of western Indonesia obese who are obese.

Methods: In this study, we examined 178 subjects consisting of 89 who are obese with BMI> 25, and controls with BMI between 18.5 and 23. Fasting blood was taken from each subject for the examination of IL-6 and CRP levels by the ELISA method. Determination of genotype -174 G>C IL-6 gene was examined by Polymerase Chain reaction- Restriction Fragment Length Polymorphism (PCR-RFLP) methods.

Results: The results of this study showed increased levels of IL-6 and CRP in the obese group compared to the controls. In the obese group, CC genotype had higher CRP and lower IL-6 levels than the GC and GG genotypes. The frequency of CC genotype in the obese group was 47.2% compared with 28.1% in controls and this genotype was considered a risk factor for obesity. Carriers of the C genotype as a dominant or a recessive model had greater risk of obesity.

Conclusion: It was concluded that the polymorphism - 174G>C IL-6 gene is a risk factor for obesity and is associated with increased levels of IL-6 and CRP in an obese group of the Western Indonesian ethnic population.