Physical activity, but not body mass index, predicts less disability before and after stroke

ObjectiveTo determine whether physical activity and body mass index (BMI) predict instrumental or basic activities of daily living (I/ADL) trajectories before or after stroke compared to individuals who remained stroke-free.MethodsUsing a prospective cohort, the Health and Retirement Study, we followed adults without a history of stroke in 1998 (n = 18,117) for up to 14 years. We estimated linear regression models of I/ADL trajectories comparing individuals who remained stroke-free throughout follow-up (n = 16,264), those who survived stroke (n = 1,374), and those who died after stroke and before the next interview wave (n = 479). We evaluated whether I/ADL trajectories differed by physical activity or BMI at baseline (before stroke), adjusting for demographic and socioeconomic covariates.ResultsCompared to those who were physically active, stroke survivors who were physically inactive at baseline had a lower probability of independence in ADLs and IADLs 3 years after stroke (risk difference = -0.18 and -0.16 for ADLs and IADLs, respectively). However, a similar difference in the probability of independence was also present 3 years before stroke, and we observed no evidence that physical activity slowed the rate of decline in independence before or after stroke. Unlike the results for physical activity, we did not observe a consistent pattern for the probability of independence in ADLs or IADLs comparing obese stroke survivors to normal-weight or to overweight stroke survivors 3 years before stroke or 3 years after stroke.ConclusionsPhysical inactivity predicts a higher risk of being dependent both before and after stroke