Genetic variant rs9939609 in FTO is associated with body composition and obesity risk in Korean females

INTRODUCTION: The fat mass and obesity-associated (FTO) gene is a significant locus in obesity. However, the association between FTO genetic variants and body composition has not been fully elucidated. RESEARCH DESIGN AND METHODS: This observational study examined the associations of FTO rs9939609 T>A with obesity and body composition markers in Koreans. A total of 6474 participants from the Korean Genome and Epidemiology Study were analyzed for their general characteristics, body composition and FTO genotype with a sex-stratified approach. RESULTS: Females with the obesity risk A allele showed significantly greater body weight, hip circumference, and body mass index and were at a 1.28-fold higher risk of obesity (95% CI=1.088 to 1.507) than those with the TT genotype. Analyses of body composition also showed that females with the A allele had a greater body fat mass and percentage, abdominal fat percentage, and degree of obesity, and this association and FTO genetic variation and adiposity was observed in females, especially aged under 50 years. However, the effect of the variant allele on non-fat tissue markers was not evident in females and was not associated with any parameters examined in males. CONCLUSIONS: The FTO rs9939609 variant is associated with body composition in Koreans, especially body fat markers in females. These results support that the FTO rs9939609 variant is a genetic risk factor in the etiology of obesity.