[Effect of Sedentary behaviors on the Interaction Between the FTO Gene and Adiposity Levels in Chilean Adults - Results from the GENADIO Study].

Background: The Fat-mass and obesity-associated-gene (FTO gene) and sedentary behavior time are associated with obesity. However, whether sedentary behavior time can modify the genetic predisposition to obesity in the Chilean population is unknown. Therefore, this study investigated the association between sedentary behavior, adiposity markers, and the FTO gene.

Methods: This cross-sectional study included 409 participants from the Genes, Environment, Diabetes, and Obesity (GENADIO) study. Adiposity markers studied included body weight, body mass index (BMI), waist circumference (WC), and fat mass. Sedentary behaviors were measured using accelerometers. Using multiple regression, we evaluated the interaction between sedentary behaviors and the FTO gene (rs9939609) on adiposity markers.

Results: Sedentary behaviors and the FTO genotype were positively associated with higher body weight, BMI, WC, and fat mass. However, the association between time of sedentary behavior and adiposity markers was higher in carriers of the risk variant for the FTO gene. For each hour of increment in sedentary behaviors, body weight increases by 1.36 kg ([95% CI: 0.27; 2.46], p = 0.015) and 2.95 kg ([95%CI: 1.24; 4.65], p = 0.001) in non-risk carriers (TT) versus risk carriers (AA), respectively. We observed similar results for WC, BMI, and body fat, but the interaction was significant only for WC.

Conclusion: The association between sedentary behaviors and adiposity markers, especially body weight and WC, is higher in individuals who carry the risk variant of the FTO gene.