C-14 Thematic Poster - Incident Disease and Mortality: JUNE 2, 2011 8:00 AM - 10:00 AM: ROOM: 403
PURPOSE: Sedentary behaviors (sitting) predominate modern life, yet we know little about the potential adverse effects of these behaviors on mortality after considering the many benefits of moderate-vigorous physical activity (MVPA). Here, we test the hypothesis that prolonged time spent in sedentary behaviors are associated with mortality independent of MVPA participation, and describe the amount of MVPA required to minimize risks associated with prolonged sedentary time.
METHODS: We evaluated 240,819 adults aged 50-71 yrs in the NIH-AARP Diet and Health Study that were free of cancer, cardiovascular, and respiratory disease at baseline. Time spent sitting, time watching television, and relevant covariates were assessed by questionnaire at baseline. Mortality was ascertained over 8.5 yrs of follow-up.
RESULTS: Sedentary behaviors were positively associated with mortality following adjustment for age, sex, smoking, dietary intake, race and MVPA. Participants reporting 7+ hrs/d of television viewing (vs. < 1 hr/d) were at greater risk for all-cause (Hazard Ratio (HR)=1.61 [95% CI, 1.47-1.76]), cardiovascular (HR=1.85 [95% CI, 1.56-2.20]), and cancer mortality (HR=1.22 [95% CI, 1.06-1.40]). Overall sitting time was only associated with all-cause mortality. Among adults who reported 4-7 hrs/wk of MVPA, television viewing for 5-6 hrs/d remained associated with a 50% increase in risk for all-cause mortality (HR=1.52 [1.30-1.79]) and a two-fold increase in risk for cardiovascular mortality (HR=1.98 [1.41-2.77]), compared to those reporting the most MVPA (7+ hrs/wk) and least television viewing (< 1 hr/d).
CONCLUSIONS: Time spent in sedentary behavior was positively associated with mortality, and participation in MVPA at or above recommended levels did not fully mitigate health risks associated with prolonged time spent watching television. Clinicians, public health, and fitness professionals should encourage the public to reduce time spent in sedentary behaviors when possible, in addition to encouraging regular participation in MVPA.