Independent associations between TV viewing and cardiometabolic health among children and youth

Abstract

PURPOSE: A previous study involving 20,871 children found no association between sedentary time and cardio-metabolic health, independent of moderate-to-vigorous physical activity (MVPA). Although many studies have examined associations between television viewing and body composition among youth, few have examined associations with cardio-metabolic risk factors. The purpose of this study was to examine associations between television viewing and cardio-metabolic risk factors among children and youth, independent of physical activity (MVPA). METHODS: Cross-sectional data collected from 7,115 children and adolescents aged 6-18 years from six studies in five countries were drawn from the International Children’s Accelerometry Database. Duration of television viewing was catergorised as: <1 hr/day; 1-2 hr/ day; 2-4 hr/day; ≥4hr/day. Generalized Linear Models were used to examine associations between television viewing and diastolic and systolic blood pressure, LDL and HDL cholesterol, triglycerides and glucose (each dichotomised based on previously published potentially abnormal/borderline screening values), adjusting for BMI, age and sex. Study was included as a dummy variables. These analyses were repeated controlling for MVPA (mins/day). Television viewing*MVPA interactions were also examined. RESULTS: There were no significant associations between TV viewing and any of the six cardio-metabolic risk factors before or after adjustment for MVPA. However, there was a significant interaction between television viewing and MVPA for a level of systolic blood pressure requiring further evaluation (OR=1.17, 95%CI=1.02-1.35). Within each category of television viewing, there was a general trend towards lower odds of high systolic blood pressure with increasing MVPA (collapsed into quartiles), with the exception of the highest category of TV viewing (≥4hr/day). There were no differences in effects across the six studies. CONCLUSIONS: In contrast to studies in adult populations, this study found little evidence of deleterious effects of television viewing on cardio-metabolic risk factors in this large and heterogenous sample of children and adolescents. However, the results suggest that MVPA may not be sufficient to reduce risk of high blood pressure among those spending ≥4hr/day watching television.