Purpose: The purpose of the current study was to investigate the associations between the GNB3 C825T polymorphism, body fatness and fitness, and blood pressure in a sample of young Korean men.
Methods: A total of 282 apparently healthy Korean men (nonobese N = 152, obese N = 130) aged 19-33 yr participated in the study. Body fatness and blood pressure were measured by using standardized protocols. The GNB3 C825T was genotyped by using polymerase chain reaction with restriction fragment length polymorphism.
Results: Univariate analyses of variance and Bonferroni post hoc tests showed that in the obese group only, TT homozygotes had a lower VO2max (P = 0.015 and 0.043, respectively) but higher resting systolic (P = 0.025 and < 0.001, respectively) and mean arterial blood pressures (P = 0.049 and 0.002, respectively) than CC homozygotes or CT heterozygotes. We further investigated possible interactions between group and genotype and found a significant interaction in SBP only (P = 0.037) between the group and genotype, even when controlling for age, BMI, and VO2max as potential confounding factors. Stepwise regression analyses showed that body mass index and GNB3 genotype were two independent predictors for the variations in systolic blood pressure and heart rate up to by 14.3 and 14.5%, respectively. In addition, waist-to-hip ratio explained an individual variation in mean arterial pressure (MAP) up to by 11.2%.
Conclusion: The current findings of the study suggest that increased body fatness along with low cardiorespiratory fitness may magnify the genetic susceptibility of the GNB3 825T allele to elevated blood pressure in this study population.