Associations between total physical activity, total physical activity transitions, and stroke among Chinese middle-aged and older people: evidence from the China Health and Retirement Longitudinal Study (CHARLS)

Stroke remains the third leading cause of mortality globally. Total physical activity (TPA) represents an individual’s overall energy expenditure across multiple domains. The associations between TPA transition patterns and stroke risk remain underexplored. This study aimed to examine the associations of baseline TPA levels and TPA transition patterns with subsequent stroke risk among middle-aged and older Chinese adults. Data were obtained from the China Health and Retirement Longitudinal Study (CHARLS) (2011–2020), which used a multi-stage stratified probability sampling design. Two prospective cohorts were established: Cohort 1 ( N = 4,094) was used to study baseline TPA levels, including participants who remained stroke-free up to the 2011 baseline with complete physical activity (PA) data, with follow-up beginning after the 2011 assessment and continuing through 2020. Cohort 2 ( N = 3,351) was used to study TPA transition patterns, including participants who remained stroke-free through the 2013 interview with complete PA data at both 2011 and 2013, with follow-up beginning after the 2013 assessment and continuing through 2020. TPA was quantified as MET-min/week and tertiled into low, medium, and high levels. TPA transition patterns were classified into nine patterns based on changes between 2011 and 2013. Univariable and multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). In Cohort 1 ( N = 4,094), compared to low-level TPA, medium-level TPA (HR 0.606, 95% CI 0.472–0.779) was associated with a lower hazard of stroke, but high-level TPA showed no significant association. In individuals with BMI ≥ 24, both medium and high-level TPA were associated with lower estimated hazard of stroke. In Cohort 2 ( N = 3,351), compared to maintaining low-level TPA, maintaining medium-level TPA exhibited the lower estimated hazard of stroke (HR 0.357, 95% CI 0.222–0.575), while transitions from low to medium, medium to low, and high to medium TPA were also associated with lower estimated hazards of stroke. In individuals with BMI ≥ 24, maintaining medium-level TPA also exhibited a lower estimated hazard of stroke. In the middle-aged and older population, either maintaining a medium-level TPA or shifting toward it from other TPA patterns is associated with a lower estimated hazard of stroke.