Sitting Time, Leisure-Time Physical Activity, and Risk of Mortality Among US Stroke Survivors: A Prospective Cohort Study From the NHANES 2007 to 2018

BACKGROUND: Stroke survivors are highly sedentary and engage in minimal physical activity. This study aimed to investigate the independent and joint effects of daily sitting time and leisure-time physical activity on survival among stroke survivors. METHODS: The nationally representative cohort included 1446 stroke survivors (weighted population, 6 968 723) from the National Health and Nutrition Examination Survey from 2007 to 2018. Mortality data were obtained through December 31, 2019. Leisure-time physical activity was categorized as inactive (0 min/wk), insufficiently active (1 to <150 min/wk), and sufficiently active (≥150 min/wk). Daily sitting time was categorized as <6, 6 to <8, and ≥8 h/d. Survival analyses of all-cause and specific mortality were performed by weighted Cox proportional hazards regression models. RESULTS: This cohort study comprised 55.0% females, 68.7% non-Hispanic White, and had a weighted mean (SE) age of 64.6 (0.5) years. Overall, 70.3% were inactive, 42.3% sat at least 8 h/d, and 34.9% were both inactive and sat at least 8 h/d. During a median of 5.2 years of follow-up, 494 deaths occurred, including 171 associated with cardiovascular disease (CVD) and 323 associated with non-CVD. Active stroke survivors had a lower risk of all-cause (hazard ratio [HR], 0.26 [95% CI, 0.17-0.40]), CVD (HR, 0.26 [95% CI, 0.13-0.53]), and non-CVD (HR, 0.26 [95% CI, 0.15-0.46]) mortality compared with inactive stroke survivors. Sitting at least 8 h/d was associated with higher risks of all-cause (HR, 1.50 [95% CI, 1.13-1.99]) and non-CVD (HR, 1.61 [95% CI, 1.18-2.20]) mortality compared with sitting <6 h/d. In the joint analyses, stroke survivors who were inactive or insufficiently active and sat for at least 8 h/d had the highest risks of all-cause (HR, 3.73 [95% CI, 2.07-6.73]), CVD (HR, 3.32 [95% CI, 1.33-8.29]), and non-CVD (HR, 3.91 [95% CI, 1.70-8.95]) mortality when compared with those who were active and sat for <6 h/d. When stratifying by leisure-time physical activity, daily sitting time was not associated with mortality among active stroke survivors. These observations were confirmed in sensitivity analyses. CONCLUSIONS: This study highlights the potential benefits of enhancing leisure-time physical activity and reducing sitting time to lower mortality rates among stroke survivors.