Objectively Measured Physical Activity, Sedentary Behavior, and Genetic Predisposition to Obesity in U.S. Hispanics/Latinos: Results From the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

Studies using self-reported data suggest a gene-physical activity interaction on obesity, yet the influence of sedentary behavior, distinct from a lack of physical activity, on genetic associations with obesity remains unclear. We analyzed interactions of accelerometer-measured moderate to vigorous physical activity (MVPA) and time spent sedentary with genetic variants on obesity among 9,645 U.S. Hispanics/Latinos. An overall genetic risk score (GRS), a central nervous system (CNS)-related GRS, and a non-CNS-related GRS were calculated based on 97 BMI-associated single nucleotide polymorphisms (SNPs). Genetic association with BMI was stronger in individuals with lower MVPA (first tertile) versus higher MVPA (third tertile) (β = 0.78 kg/m2 [SE, 0.10 kg/m2 ] vs. 0.39 kg/m2 [0.09 kg/m2 ] per SD increment of GRS; P interaction = 0.005), and in those with more time spent sedentary (third tertile) versus less time spent sedentary (first tertile) (β = 0.73 kg/m2 [SE, 0.10 kg/m2 ] vs. 0.44 kg/m2 [0.09 kg/m2 ]; P interaction = 0.006). Similar significant interaction patterns were observed for obesity risk, body fat mass, fat percentage, fat mass index, and waist circumference, but not for fat-free mass. The CNS-related GRS, but not the non-CNS-related GRS, showed significant interactions with MVPA and sedentary behavior, with effects on BMI and other adiposity traits. Our data suggest that both increasing physical activity and reducing sedentary behavior may attenuate genetic associations with obesity, although the independence of these interaction effects needs to be investigated further.