Association Between Sitting Time and Physical Activity With Survival Among Stroke Survivors: A National Cohort Study

OBJECTIVE: To assess the independent and joint effects of sitting time and moderate-to-vigorous intensity physical activity (MVPA) on mortality in stroke survivors. DESIGN: Retrospective study of prospective cohort data from the National Health and Nutrition Examination Survey (NHANES) 2007-2018. SETTING: NHANES, a nationally representative US survey that combines in-home interviews and standardized physical examinations conducted in mobile examination centers. PARTICIPANTS: A total of 1312 adult stroke survivors were included, representing a weighted population of 6617,365 individuals. Participants were followed for mortality outcomes through December 31, 2019. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: All-cause and cardiovascular disease (CVD)-specific mortality ascertained from the National Death Index. RESULTS: Over a median follow-up of 4.85 years, there were 438 deaths, including 151 because of CVD. Sitting ≥8 h/d was associated with higher risks of all-cause mortality (hazard ratio [HR], 1.73; 95% confidence interval [CI], 1.25-2.40) and CVD-specific mortality (HR, 1.97; 95% CI, 1.04-3.74). A statistically significant interaction between sitting time and MVPA was observed for all-cause mortality (P for interaction=.006). Participants with both prolonged sitting and