Abstract

Background: A single-nucleotide polymorphism, C825T in the G protein β3 subunit (GNB3) gene, is associated with essential hypertension and obesity. However, the potential interaction of the GNB3C825T polymorphism with obesogenic environmentsin obesity of Korean children has not been closely evaluated yet.
Methods: We analyzed data collected from 635 boys and 627 girls aged 8-9 yearsrecruited from seven elementary schools in Seoul, South Korea. Measures of anthropometry and blood pressure (BP) as well as fasting blood samples were used in the analysis. Three-day food records were collected.
Results: Obese children had higher BP, lipid profiles and insulinresistance-related factors than did lean children. Higher body mass index (BMI), waist circumference (WC)and BP and lowerplasma lipid profiles were observed in boys than in girls. The genotype frequencies of the GNB3 polymorphism were CC=23.7%, CT=52.1%, and TT=24.2%, and the allele frequencies were C allele=49.7% and T allele=50.3 in the subjects. There was no significant difference according to gender and obesity with allelic frequencies. Boys with the T allele were more obese thanthose with the C allele, but the C and T alleles, according to anthropometrics and plasma variables, did not differ between the obesity and lean groups. In contrast to boys, obese girls with the T allele had lower BMI and WC than those with the C allele, although they had higher plasma cholesteroland energy intakes compared to those with the C allele. We found that the HDL_3c subtype, fasting insulin and homeostasis model assessment of insulin resistance decreased with increasing HDL peak amount, which was positively correlated with total HDLcholesterol. However, the HDL subtypes were not changed by the GNB3 C825T polymorphism.
Conclusion: The GNB3 C825T polymorphism influences the childhood obesity rate and energy intakesdifferentially by gender in Korean children.