DNA polymorphisms of the apolipoprotein B gene are associated with obesity and serum lipids in healthy Indians in Singapore.

Three DNA polymorphisms (Ins/Del, XbaI and EcoRI) of the apolipoprotein B gene and their influence on body-mass index, serum lipids and apolipoprotein levels were studied in 181 healthy Indians of both sexes (121 males and 60 females), aged between 17 and 71 years. The frequencies of X+ (XbaI) and Del (Ins/Del) of the signal peptide region in Indians were found to be significantly lower (0.17 and 0.11, respectively) compared to the frequencies in Caucasians (0.50 and 0.32, respectively) (P < 0.025). The frequency of E- (EcoRI) was similar to that in Caucasians (0.10 vs 0.15). A highly significant linkage disequilibrium was observed between the XbaI site and Ins/Del polymorphism of the apo B gene in this sample (X2 = 31.9, P < 0.001). The simultaneous presence of Del and X+ allele was significantly associated with higher body mass index (X2 = 11.43, P < 0.005), serum total cholesterol (X2 = 5.11; P < 0.025) and triglyceride (X2 = 6.42; P < 0.025) levels. Mean values of adjusted BMI and serum triglyceride levels were found to be 29.0 +/- 1.92 vs 23.7 +/- 0.67 (P < 0.025) and 278.0 +/- 60.78 vs 140.4 +/- 15.43 mg/dl (P < 0.05), respectively, in subjects with Del and X+ compared to others. The multiple regression tests showed that 3.3 and 5.8% of the total variability of BMI is explained by Ins/Del and XbaI polymorphism, respectively, in this sample (P = 0.06 and 0.02), while 3.8% of serum triglyceride levels was explained by Ins/Del polymorphism of the apo B gene (P = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)