Interleukin-1 receptor antagonist gene polymorphism and obesity: A pilot study from north India

Abstract

The main adverse consequences of excess bodyweight are cardiovascular disease, type II diabetes, and several cancers, IL-1Ra serum concentration has been reported earlier to increase in human obesity and it is therefore assumed that the polymorphism of IL-1Ra may influence cytokine production. We designed this study to investigate whether the IL-1Ra polymorphism was associated with obesity. A total number of 103 individuals; 19 lean (BMI<25 Kg/m²), 51 overweight (BMI 25–29.9 Kg/m²) and 33 obese (BMI≥30.0 Kg/m²) were enrolled in this study. Genotyping was performed using a polymerase chain reaction PCR amplification of the intron-2 fragment harboring a variable number of tandem repeat (VNTR) nucleotide sequences 86 pb of tandem repeat. The PCR products were separated on 2% agarose gel. Statistical analysis was performed using SPSS software (version 11.5). We found no significant difference in genotype and allele frequencies between the three groups; lean vs. overweight and lean vs. obese (p=0.323; 0.202; 0.123 and 0.068 resp). However, an increased risk for obesity had a propensity to be higher in those having genotype II/II. This genotype has been reported to be a ‘high producer’ of IL-1Ra. Although no statistically significant relationship between IL-1Ra polymorphism and BMI was observed, however, a trend towards an increase of allele^*II in overweight and obese group was observed. This may suggest that IL-1Ra appears to be induced by inflammatory stimuli as well as obesity-associated factors. This is relatively a pilot study: but nevertheless, may assist in identifying the pathophysiological cause for obesity.