Night sleep duration and sleep initiation time with hypertension in Chinese rural population: the Henan Rural Cohort.

BACKGROUND: The study was conducted to evaluate the independent dose-response of the night sleep duration and sleep initiation time on hypertension, and to explore their combined effect with hypertension. METHODS: Participants from the Henan Rural Cohort were enrolled in this study. Information on sleep was collected using the Pittsburgh Sleep Quality Index. Hypertension was defined as systolic blood pressure/diastolic blood pressure ≥140/90 mmHg or self-reported hypertension and current use of anti-hypertensive medicines. Logistic regression and restricted cubic spline were conducted to evaluate the association of night sleep duration and sleep initiation time with hypertension. RESULTS: Of the 37 317 included participants, 12 333 suffered from hypertension. 14 474 (38.79%) were men and 22 843 (61.21%) were women, the mean age were 57.18 ± 12.10 and 55.24 ± 11.98 in men and women. Compared to reference (7-h), fully adjusted odd ratios (ORs) and 95% confidence interval (CI) of hypertension were 0.91 (0.66-1.25) in <5 h group and 1.74 (1.41-2.16) in ≥10 h among men, respectively. Fully adjusted ORs (95% CIs) for hypertension compared with reference (21:00-22:00) were 1.05 (95% CI 0.78-1.41) in the <20:00 group, 1.52 (1.25-1.85) in ≥24:00 in men. The combined effect of sleep duration and sleep initiation time on hypertension were statistically significant in the category of (≥8 h)/night and ≥24:00 (OR 1.87, 95% CI 1.07-3.25) compared to reference in fully adjusted model among men. CONCLUSIONS: Long night sleep duration and late sleep initiation time were associated with the higher odds of hypertension, and the sleep duration and sleep initiation time might cumulatively increase the prevalence of hypertension in men. CLINICAL TRIAL REGISTRATION: The Henan Rural Cohort Study has been registered at the Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). http://www.chictr.org.cn/showproj.aspx? proj=11375.