Objective: Genetic variants in the fat mass and obesity-associated (FTO) gene have been linked with obesity and type 2 diabetes in European populations. We aimed to test the role of FTO genetic variants in obesity and type 2 diabetes in the Chinese population.
Research design and methods: We genotyped 19 single-nucleotide polymorphisms (SNPs) spanning from the 3' end of the neighboring RPGRIP1L gene to the 5' flanking region of the FTO gene. We analyzed their associations with obesity (638 case and 1,610 control subjects), type 2 diabetes (759 case and 784 control subjects), and obesity-related traits in nondiabetic subjects.
Results: Among the 19 SNPs, the rs9939609 A allele was strongly associated with obesity (P = 7.0 x 10(-4)) and BMI (P = 0.0024) in the Chinese population. The odds ratio for obesity was 2.60 (95% CI 1.24-5.46) (P = 0.011) for the AA genotype and 1.32 (1.05-1.66) (P = 0.018) for the AT genotype compared with the TT genotype. Each additional copy of the rs9936609 A allele was associated with a BMI increase of approximately 0.37 kg/m(2). The rs9939609 A allele was substantially less common in the Chinese population than in the European population (12.6 vs. 45%). We did not find significant associations of the 19 SNPs with type 2 diabetes or other obesity-related traits.
Conclusions: Genetic variation in the FTO gene is strongly associated with obesity and BMI in the Chinese population. The risk variant is less common in the Chinese population, but its effect size on BMI is comparable with that in the European population.