Television viewing time and 13-year mortality in adults with cardiovascular disease: data from the Australian Diabetes, Obesity and Lifestyle Study (AusDiab)

BACKGROUND: In the general population, excessive sedentary behaviour is associated with increased all-cause mortality. Few studies have examined this relationship in people with cardiovascular disease (CVD). Using a sample of people with CVD who were excluded from an analysis of the Australian Diabetes, Obesity and Lifestyle (AusDiab) study, we examined the relationship between sedentary behaviour and 13-year all-cause mortality. METHODS: In the original AusDiab study, television viewing time was used as a marker of sedentary behaviour in 609 adults (≥45 years of age) with CVD. During 6,291 person-years of follow-up (median follow-up 13 years), there were 294 deaths (48% of sample). Using the time scale of attained age, the Cox proportional hazards model predicting all-cause mortality adjusted for sex, self-rated general health, leisure-time physical activity, smoking status, education, household income, body mass index, lipid levels, blood pressure, and diabetes mellitus was used. RESULTS: Compared with a TV viewing time of <2hours per day, the fully adjusted hazard ratios for all-cause mortality were 1.18 (95% CI, 0.88 to 1.57) for ≥2 to <4hours per day and 1.52 (95% CI, 1.09 to 2.13) for >4hours per day. CONCLUSIONS: Sedentary behaviour was associated with increased risk of all-cause mortality in people with CVD, independent of physical activity and other confounders. In addition to the promotion of regular physical activity, cardiac rehabilitation efforts which also focus on reducing sedentary behaviour may be beneficial.