Study of seven single-nucleotide polymorphisms identified in East Asians for association with obesity in a Taiwanese population

Objective: This study aimed to examine single-nucleotide polymorphisms (SNPs) of seven previously reported obesity genes in East Asians and to analyse their associations and synergistic effects on obesity in the Taiwanese population. Design: Cross-sectional study. Setting: One medical centre in northern Taiwan. Participants: A total of 323 non-obese and 264 obese participants were recruited. The threshold for obesity in this study was a body mass index of >= 27 kg/m(2), as defined by the Ministry of Health and Welfare in Taiwan. The study was performed with the approval of the institutional review board of MacKay Memorial Hospital, Taipei, Taiwan (application number 12MMHIS106). Outcome measures: We analysed the genotype distributions of seven SNPs localising to the PPAR.2, GNB3, SDC3, ADRB2, FTO, PPAR. and ESR1 genes in obese and non-obese groups and then paired obesity-related SNPs to determine if they have synergistic effects on obesity. Results: Analysis of the genotype distributions in obese and non-obese groups revealed only a significant positive correlation between an SNP in rs2282440-syndecan 3 (SDC3) and obesity in the Taiwanese population (p=0.006). In addition, the T/T genotype of SDC3 was significantly associated with a larger waist and hip circumference, higher body fat percentage and lower high-density lipoprotein cholesterol. Moreover, the combination of the rs2282440-SDC3T/T genotype with the rs1801282-peroxisome proliferator-activated receptor-gamma2 gene (PPAR.2) G carrier genotype was strongly associated with obesity (OR=6.77). Conclusions: We found that the rs2282440-SDC3T/T genotype is associated with obesity in the Taiwanese population. Furthermore, there is a synergistic effect of the high-risk alleles of the SDC3 and PPAR.2 genes on the obese phenotype in the Taiwanese population.