Our study replicates the association between variants in the FTO gene and obesity-related traits (eg, BMI, body weight, waist circumference, and percentage of body fat) recently reported by others.1–3,13–15 Furthermore, we have shown that the association of genotype on body composition is much smaller and not statistically significant in subjects having higher physical activity levels. The SNPs most strongly associated with BMI in our study were rs1861868 and rs1477196, both of which are common in the OOA (0.49 and 0.35, respectively) and in non-OOA white individuals (0.48 and 0.28, respectively). These SNPs are in higher LD in the OOA (D′= 0.84; r2=0.36) than in non-OOA European white individuals (HapMap genotypes from white individuals, D′=0.61, r2=0.15). Greater LD in the OOA compared with the general white population might be expected because the OOA are a relatively young founder population. Although an association of rs1477196 with obesity (P=6.0×10−9 based on an additive model) has previously been reported in a study of French adults,2 to our knowledge, the association of rs1861868 with BMI or obesity has not been described. In our analyses, a
