Evaluation of single nucleotide polymorphisms of Pro12Ala in peroxisome proliferator-activated receptor-γ and Gly308Ala in tumor necrosis factor-α genes in obese Asian Indians: a population-based study

BACKGROUND A population-based case control study was performed to determine the associations of Pro12Ala polymorphism in peroxisome proliferator-activated receptor-γ (PPARG) and Gly308Ala polymorphism in tumor necrosis factor-α (TNFA) genes in obese subjects. PATIENTS AND METHODS Of 1,400 eligible subjects, ≧20 years, we recruited only 1,127. For extreme phenotype case-control design, we evaluated 201 subjects with body mass index (BMI) ≧30 kg/m(2) (Group 1) and 143 with BMI <20 kg/m(2) (Group 2). Clinical, anthropometric, biochemical, and nutritional details and polymorphisms were estimated. RESULTS In Group 1, the dietary intake of calories and fats was higher, physical activity was lower, and prevalence of truncal obesity, hypertension, high total cholesterol, low high-density lipoprotein cholesterol, and diabetes was greater than in Group 2. There were no homozygous polymorphisms of either gene. Heterozygous Pro12Ala polymorphism in PPARG was found in 15 (7.5%) subjects in Group 1 and 3 (2.1%) subjects in Group 2 (P = 0.028), and heterozygous Gly308Ala polymorphism in TNFA was found in 19 (9.5%) in Group 1 and 7 (4.9%) in Group 2 (P = 0.115). Presence of heterozygous polymorphism in PPARG and TNFA-predicted obesity with univariate odds ratio ([OR], 95% confidence intervals) of 2.25 (1.32-3.84, P = 0.003) and 1.48 (1.10-1.99, P = 0.009) and with multivariate OR 1.74 (1.03-2.93, P = 0.038) and 1.46 (1.05-2.03, P = 0.024), respectively. The addition of dietary and physical activity variables did not result in significant change. CONCLUSION Obese Asian Indians have greater prevalence of heterozygous polymorphisms of Pro12Ala in PPARG and Gly308Ala in TNFA genes.