Effects of Adiponectin Genotypes on Susceptibility of Obesity in Healthy Koreans

¹Ji Wan Park, ²Jungyong Park, ³Hyon Suk Kim, ⁴Jeong Ho Kim, ¹Joo Bae Park, ³Sun Ha Jee
¹Dept. Molecular and Cellular Biology, School of Medicine, Sungkyunkwan University, 300 Cheoncheon-dong, Jangan-gu, Suwon, Gyeonggi-do 440-746, South Korea, ²Inst. Health Promotion, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749, South Korea, ³Dept. Epidemiology and Health Promotion, Graduate School of Public Health, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749, South Korea, ⁴Dept. Laboratory Medicine, College of Medicine, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749, South Korea

Obesity is a well known risk factor for various diseases including diabetes mellitus and cardiovascular disease. This study aims to measure the association between adiponectin, C1Q and collagen domain containing (ADIPOQ) gene, which regulates metabolisms of lipids and glucose in plasma, and obesity in Koreans. Three single nucleotide polymorphisms (SNPs) located in the ADIPOQ gene were genotyped in 986 healthy Koreans. Allelic and genotypic associations of this gene with obesity were measured using logistic regression analyses after adjustments for age, gender, smoking and alcohol consumption in three sets of comparison groups (e.g. G1, the most obese group vs. the skinniest group) defined by the level of both body mass index and adiponectin. The C allele (OR 1.48, 95% CI 1.13-1.94) of rs266729 (-11377G/C), a polymorphism located in the promoter region of ADIPOQ gene, and most of haplotypes including this allele increased the risk of obesity. For instance, the risk of obesity among those with CG and CTG haplotypes composed of rs266729-rs2241766(45G/T)/rs1501299(276T/G) and rs266729-rs2241766-rs1501299, respectively, were 2.13 (1.05-4.32), 3 (1.46-6.15) and 2.98 (1.19-7.41)-fold higher compared to the reference group. The statistical evidence from the CT/CT diplotype of rs266729-rs2241766 confirmed the contribution of C allele predisposes to obesity (OR 2.44, 1.08-5.54). The statistical significance seen across all three sets of comparison indicates that a strict definition on phenotype increases the power to detect evidence for association. These results suggest the contribution of the ADIPOQ gene to susceptibility of obesity in healthy Koreans. High risk genotypes and haplotypes identified here may provide more information in identifying individuals who are at risk of obesity.