Physical inactivity is known to be a risk factor for cardiovascular diseases (CVD), type 2 Diabetes (DM2) and all-cause mortality.
Television viewing is the most prevalent sedentary behaviour, and in a recent issue of the Journal of the American Medical Association (JAMA), Grontved and Hu report a meta-analysis on the relation between television viewing and the risk of CVD, DM2 and all-cause mortality.
The pooled relative risks per 2 hours of television viewing per day were 1.20 (95% CI 1.14-1.27) for DM2, 1.15 (95% CI 1.06-1.23) for CVD and 1.13 (95% CI 1.07-1.18) for all-cause mortality. The estimates were adjusted for a number of confounders, amongst which specific dietary habits. However, some residual confounding cannot be ruled out.
It remains to be shown whether decreasing the amount of time spent watching television will reduce the risks.