Relationship between leptin gene variants (-2548G>A and 19A>G) and obesity among north Indian Punjabi population

Leptin is an adipocyte-secreted hormone which is involved in the regulation of food intake and energy expenditure. To ascertain the potential association between leptin gene (LEP) -2548G>A and 19A>G polymorphisms and obesity risk in the north Indian Punjabi population, a group of 250 obese and 300 control subjects were randomly selected. Both the polymorphisms in the LEP gene -2548G>A (GG vs AA: odds ratio (OR), 1.44; 95% confidence interval (CI), 0.87-2.38) and 19 A>G (AA vs GG: OR, 2.31; 95% CI, 1.32-4.05) were significantly associated with an increased risk of obesity. Logistic regression analysis revealed the significant associations in a recessive genetic model (OR=2.061; 95% CI: 1.14-3.73) and (OR= 2.57; 95% CI: 1.43-4.63) respectively for -2548G>A and 19A>G polymorphisms after adjusting for various covariates of obesity, thus, confirming the major role of anthropometric and environmental factors in this population. Haplotype analysis identified that G-G haplotype conferred approximately two-fold increased obesity risk (P=0.002). The -2548A allele and the selected obesity related covariates accounted for 53%, 26% and 30.2% variability in body mass index (BMI), waist-to-hip ratio (WHR) and triglycerides (TG), respectively. Similarly, the 19G allele contributed 75%, 27% and 36% of the variability in the waist circumference (W-crc), and WHR and TG levels, respectively in the obese individuals. Therefore the present study has revealed that both LEP -2548G>A and 19A>G polymorphisms have an important role in a individual's susceptibility towards obesity and thus could serve as relevant obesity markers in the north Indian Punjabi population.