Prospective Analysis of the Association of a Common Variant of FTO (rs9939609) with Adiposity in Children: Results of the IDEFICS Study

Objectives: We investigated cross-sectionally and longitudinally the relationship between FTO rs9939609 and obesity-related characteristics in the European children of the IDEFICS project and the interaction of this variant with a lifestyle intervention. Population and Methods: A cohort of 16224 children (2-9 years) was recruited into a population-based survey (T0) from eight European countries. A second survey (T1) reassessed the children two years later. A random sample of 4405 children was extracted for genetic studies. 3168 children were re-examined two years later. Half of them underwent a lifestyle intervention program. The FTO rs9939609 was genotyped. Weight, height, waist circumference, triceps and subscapular skinfolds were measured at T0 and T1. Results: At T0, the risk A allele of rs9939609 was significantly associated with higher values of body mass index (BMI), waist circumference and skinfolds (age, sex, and country-adjusted p-values: all pA = 1.95, 95% CI = (1.29; 2.97)]. Conclusions: We confirmed the association between the FTO rs9939609 and body mass and overweight/obesity risk in European children. The main finding of the study is that the A allele carriers present higher increase of body mass and central adiposity over time and higher risk of developing overweight/obesity during growth, independently from intervention measures.