The determinants of functional limitation trajectories after stroke remain scarce. This study aimed to investigate the association of early body mass index (BMI) changes with trajectories of activities of daily living (ADLs) and instrumental activities of daily living (IADLs) following stroke.

Three cohorts from Europe and the United States.

Community.

Stroke survivors.

BMI changes were assessed 1–4 years after self-reported stroke and categorized as decreased (≤−5% initial BMI), increased (≥5% initial BMI), and stable. An alternate cut-point of 2% was also used. Functional limitations were measured as the number of ADL and IADL limitations, which were repeatedly measured for up to 24 years after stroke. Associations were evaluated using segmented linear mixed-effects models after adjusting for demographic, behavioral, and medical factors.

The study population comprised 2544 adults with stroke (mean [standard deviation] age 70.0 [10.9] years; 52.0% women). Based on a 5% cutoff, the number of ADL and IADL limitations was higher in the groups of decreased (ADL: 0.56 [95% CI = 0.28, 0.85]; IADL: 0.66 [95% CI = 0.38, 0.94]) and increased BMI (ADL: 0.55 [95% CI = 0.28, 0.81]; IADL: 0.59 [95% CI = 0.33, 0.85]) compared to stable BMI, respectively. Similar findings were obtained for a 2% cutoff. These differences frequently persisted for 24 years for decreased BMI and 6–12 years for increased BMI.

Early decreased BMI, and to a lesser extent increased BMI, following stroke could be a marker of long-term adverse trajectories of physical functioning, underlying the importance of nutritional and physical activity management after a stroke.