Background: Obstructive sleep apnea (OSA) is emerging as a significant disorder in India. Tumor necrosis factor-alpha (TNFalpha) is an important marker of inflammation. Recent data indicate that inflammation may be an important correlate of OSA. The relationships of OSA with TNFalpha levels and TNFalpha gene promoter polymorphism (-308G/A) have not been investigated in obese Asian Indians with OSA.
Objective: To look for the correlation if any, between TNFalpha gene promoter polymorphism (-308G/A) in obese Asian Indians with and without OSA and correlation of TNFalpha levels with severity of OSA.
Methods and results: We studied 207 obese (BMI>25kg/m(2)) subjects; 104 with OSA and 103 without OSA. Both groups were matched for age, body mass index (BMI) and percentage body fat (%BF). Measurements included anthropometric and biochemical (fasting blood glucose, lipid profile and serum TNFalpha levels) parameters and TNFalpha gene promoter polymorphism (-308G/A). The frequency of '-308A'allele in TNFalpha gene was significantly higher in obese subjects with OSA (28.8%; 60/208), when compared with obese subjects without OSA (12.6%; 26/206, p=0.001). Serum TNFalpha levels were significantly higher in obese subjects with OSA [(3.6+/-0.8)pg/ml], when compared with obese subjects without OSA [(3.3+/-0.6)pg/ml, p=0.009].
Conclusions: Frequency of TNFalpha (-308A) allele and serum TNFalpha level was significantly higher in obese Asian Indians with OSA.