B-15 Free Communication/Slide - Sedentary Behavior: MAY 27, 2009 1:00 PM - 2:45 PM ROOM: 619
Physical inactivity is a risk factor for premature mortality. However, the role of prolonged sedentary behavior (as distinct from lack of physical activity) in relation to mortality risk is less clear. Television (TV) viewing, which accounts for a high proportion of adults' discretionary sedentary time, has been associated with increased cardio-metabolic risk, but its relation with mortality is not known.
PURPOSE: We examined TV time in relation to subsequent all-cause mortality and cardiovascular disease (CVD) mortality among 9,303 adults aged ≥ 25 years in the Australian Diabetes, Obesity and Lifestyle Study (AusDiab).
METHODS: TV time was assessed at baseline in 1999-2000 using interviewer-administered questionnaires. Mortality follow-up was conducted through to November 2006 (median follow-up: 6.6 years). Cox proportional hazards regression models were adjusted for age, sex, smoking status, education, past history of self-reported CVD, diet and leisure-time physical activity and cardio-metabolic risk markers, including waist circumference.
RESULTS: There were 368 deaths (124 due to CVD). Compared to those who watched TV for 0-1.9 hrs/day, the multivariate adjusted hazard ratios (HRs) (95% confidence interval) for all-cause mortality were 1.08 (0.85-1.36) for 2.0-3.9 hrs/day and 1.42 (1.06-1.92) for ≥ 4 hrs/day. For CVD, the corresponding HRs were 1.01 (0.67-1.52) and 1.68 (1.04-2.71) respectively.
CONCLUSIONS: Independent of leisure-time physical activity, TV time was associated with a significantly increased risk of all-cause and CVD mortality among those watching more than 4 hours of TV per day. These results suggest that, in addition to the promotion of regular physical activity, preventative efforts could also be directed at reducing prolonged sitting; TV time may be an amenable target.