Impact of sedentary behavior and physical activity on stroke risk in a cohort of patients with silent brain infarction.

Silent brain infarction (SBI) is associated with a markedly increased risk of subsequent stroke. Identifying actionable, modifiable risk factors for stroke prevention is essential. Physical activity (PA) is a known protective factor, but the specific impact of sedentary behavior on stroke risk in SBI patients and its interaction with PA remain unclear. This study examines the independent and joint effects of sedentary time (ST) and PA on stroke risk in SBI patients. In this prospective cohort study, we used health check-up data from Chinese hospitals for SBI patients and followed participants for incident stroke. ST and PA were assessed at baseline. The dose–response relationship between ST and stroke risk was evaluated with restricted cubic spline regression. Cox proportional hazards models estimated the independent effects of ST, Moderate-to Vigorous Intensity Physical Activity (MVPA), and their joint effects on stroke risk. Compared with ST < 8 h/day, ST ≥ 8 h/day was associated with a substantially higher risk of stroke (HR, 4.20 [95% CI, 2.23–7.93]); For joint effects, compared with the reference group (ST < 8 h/day & MVPA ≥ 300 min per week (min/wk)), the group with ST ≥ 8 h/day and MVPA ≥ 300 min/week had (HR 3.32 [95% CI 1.11–9.89]). Prolonged sedentary time (≥ 8 h/day) is an independent risk factor for stroke in SBI patients. Engaging in ≥ 300 min/week of MVPA attenuates the adverse association between ST and stroke risk. Reducing sedentary behavior and achieving adequate MVPA may be important for stroke risk management in SBI patients.