Does meeting physical activity recommendations ameliorate association between television viewing with cardiovascular disease risk? A cross-sectional, population-based analysis

Objectives: As a common form of sedentary behaviour, television viewing is associated with an increase in body mass index (BMI) as well as overall cardiovascular disease (CVD) risk. This study examined the extent to which meeting the recommended volume of weekly physical activity (PA) reduced the association between television viewing with the outcomes of BMI and CVD risk. A second aim was to determine the number of hours (ie, cut-point) of daily television viewing that conferred a higher BMI and CVD risk for a large population-based sample of adults. Design: Population-based, cross-sectional study. Setting UK Biobank recruited across 35 centres in the UK between 2006 and 2010. Primary outcome CVD risk, as measured by the 30-year Framingham risk score. Results Linear regression models indicated that every additional hour of television viewing per day was associated with a 3% increase in CVD risk (aCoeff=0.03, d=0.16, p<0.0001); the interaction between television viewing with meeting PA guidelines was marginally associated with CVD risk (aCoeff=0.0010, d=0.01, p=0.014). Each additional hour of television viewing per day was associated with a 0.54 increase in BMI (aCoeff=0.54, d=0.13, p<0.0001); the interaction between television viewing with meeting PA guidelines was not significantly associated with BMI. Regression tree models of the study outcomes revealed that 2.5 hours of television viewing was associated with pronounced increases in BMI and CVD risk. Conclusions: These data underscore the independent association between television viewing with cardiovascular risk and suggest that reducing television viewing to less than 2.5 hours per day, even in physically active adults, is a clinical and public health priority.