Effects of UCP2 and UCP3 variants on the manifestation of overweight in Korean children.

To investigate the associations of uncoupling protein (UCP)2 and UCP3 gene variants with overweight and related traits, we genotyped UCP2-866G>A, UCP2Ala55Val, and UCP3-55C>T in 737 Korean children and 732 adults and collected data regarding anthropometric status and blood biochemistry. Information concerning the children's lifestyles and dietary habits was collected. The UCP2-866G>A and UCP3-55C>T gene variants showed significant associations with BMI level, waist circumference, and body weight in the children but not in the adults. Compared with -866GG carriers, the -866GA and AA carriers showed a strong decreasing trend in the risk for overweight (odds ratio (OR), 0.67; 95% confidence interval (CI), 0.45-1.01; P = 0.053). In comparison with UCP3-55CC carriers, children carrying -55CT and TT showed a significant reduction in the risk of overweight (OR, 0.67; 95% CI, 0.46-0.98; P = 0.039). There was also evidence of interactions between the effects of the combined UCP2-UCP3 genotype and obesity-related metabolic traits. The greatest protective effect against overweight was seen in those with the combined genotype non-UCP2-866GG and non-UCP3-55CC, as compared with those carrying both UCP2-866GG and UCP3-55CC (OR,0.60; 95% CI, 0.38-0.95; P = 0.030). In the subgroup with a low level of physical activity, UCP3-55CC carriers had higher BMI values than UCP3-55T carriers (16.6 +/- 2.3 kg/m(2) vs. 16.1 +/- 1.9 kg/m(2), P = 0.016). Low physical activity may aggravate the susceptibility to overweight in UCP2-866GG and UCP3-55CC carriers.