Effect of hypertension status on the association between sleep duration and stroke among middle‐aged and elderly population

We aimed to examine whether hypertension status modified the association between sleep duration and stroke among middle‐aged and elderly population. This cross‐sectional study included 10 516 participants aged ≥45 years from the China Hypertension Survey study. Sleep duration and history of stroke were assessed by questionnaires. Multivariate logistic regression analyses, a generalized additive model (GAM) and smooth curve fitting (penalized spline method) and a two‐piecewise logistic regression models were performed to evaluate the association between sleep duration and stroke in different status of hypertension. 95% confidence interval (CI) for turning point was obtained by bootstrapping. Multiple logistic analyses showed that per 1 hour increase in sleep duration was associated with a 37% increased prevalence of stroke among participants without hypertension and associated with a 8% increased prevalence of stroke among hypertensive participants (without hypertension: odds ratio [OR] = 1.37, 95% CI 1.09‐1.71; with hypertension: OR = 1.08, 95% CI 0.95‐1.21; P Interaction  = .029). The fully adjusted smooth curves presented a linear association between sleep duration and stroke among participants without hypertension, but a threshold, nonlinear association among hypertensive participants. The turning point for the curve was found at a sleep duration of 8 (95% CI 5‐9) h among hypertensive patients. The ORs (95% CIs) for stroke were 0.92 (0.79, 1.06) and 1.60 (1.23, 2.08) to the left and right of the turning point, respectively. In conclusion, we found a linear association between sleep duration and stroke among middle‐aged and elderly participants without hypertension, but a threshold, nonlinear association among hypertensive participants.