Sedentary Behaviors and Cardiometabolic Risk: An Isotemporal Substitution Analysis

Evidence suggests that time spent engaging in sedentary behaviors is associated with a greater risk of adverse cardiometabolic outcomes. We investigated the cross-sectional associations of 6 unique sedentary tasks (watching television, using the computer, completing paperwork, reading, talking on the telephone, and sitting in a car) with cardiometabolic risk factors, and also examined the effect of replacing one type of sedentary behavior with another on the level of cardiometabolic risk. Participants consisted of 3,211 individuals from the Coronary Artery Risk Development in Young Adults Study who visited the clinic between 2010 and 2011. Linear regression models examined the independent and joint associations of sedentary tasks with a composite cardiometabolic risk score, as well as with individual cardiometabolic risk factors (waist circumference, blood pressure, fasting glucose, insulin, triglycerides, and high density lipoprotein cholesterol) after adjusting for physical activity and other covariates. Replacing 2 hours of television viewing with 2 hours spent performing any other sedentary activity was associated with a lower cardiometabolic risk score of 0.06-0.09 standard deviations (all 95% confidence intervals: -0.13, -0.02). No other replacements of one type of sedentary task for another were significant. Study findings indicate that television viewing has a more adverse association with cardiometabolic risk factors than other sedentary behaviors.