Associations of -308G/A polymorphism of tumor necrosis factor (TNF) - α gene and serum TNF-α levels with measures of obesity, intra-abdominal and subcutaneous abdominal fat, subclinical inflammation and insulin resistance in Asian Indians in north India

Objectives: Obesity is associated with high levels proinflammatory cytokines like tumour necrosis factor alpha (TNF-alpha), which may play an important role in the genesis of insulin resistance. We evaluated the relationship of -308G/A polymorphism of TNF-alpha gene with obesity and insulin resistance in Asian Indians in north India. Methods: This cross-sectional study included 151 apparently healthy individuals (79 males, 72 females) 18-50 yrs of age from New Delhi, India. Body composition by dual-energy x-ray absorptiometry (DEXA) and abdominal fat by magnetic resonance imaging (MRI) were measured. Biochemical measurements included OGTT, lipids, fasting insulin, hs-CRP and TNF-alpha levels. We analysed -308G/A polymorphism of TNF-alpha gene and studied its association with obesity and biochemical parameters. Results: At comparable BMI, abdominal obesity was more prevalent in females (50%) as compared to males (20%). The wild genotype (GG) was present in 78.8%, GA in 17.9%, and AA in 3.3% subjects. Measures of body composition, abdominal fat distribution, lipids, insulin, hs-CRP and TNF-alpha levels were not influenced by the presence of -308G/A polymorphism. Serum TNF-alpha levels correlated significantly with fasting insulin in both genders. Conclusion: TNF-alpha levels correlate with fasting insulin but not with indicators of body composition in Asian Indians. The -308G/A polymorphism of TNF-alpha gene is not associated with differences in the serum levels of TNF-alpha in Asian Indians.