The associations between sleep timing and night sleep duration with dyslipidemia in a rural population: The Henan Rural Cohort Study.

Evidence linking sleep timing and night sleep duration to dyslipidemia was limited and inconclusive, especially among low- and middle-income adults. The aims were to evaluate the associations between sleep timing, night sleep duration and dyslipidemia in a rural population. Based on the Henan Rural Cohort Study, a total of 37 164 participants were included. The Pittsburgh Sleep Quality Index was used to collect sleep information. Logistic regression and restrictive cubic splines were conducted to explore the associations. Of the 37 164 enrolled participants, 13881 suffered from dyslipidemia. Compared to the reference groups, people who went to sleep after 23:00 or woke up after 7:30 had higher prevalence of dyslipidemia, the adjusted odds ratios ( ORs ) and 95% confidence intervals ( CIs )were 1.30 (1.20-1.41) and 1.34 (1.19-1.50). The adjusted OR (95% CI ) of participants in the Late-sleep/Late-rise category compared to the Early-sleep/Early-rise category was 1.55 (1.08-1.23). Compared to the reference (7~≤8 h), the adjusted OR (95% CI ) was 1.11 (1.03-1.20) for longer (>9 h) night sleep duration. Moreover, the combined effects of sleep duration (>9 h) with sleep time (22:00~) ( OR  = 1.46, 95% CI : 1.16-1.84), sleep duration (>9 h) with wake-up time (≥7:30) ( OR  = 1.28, 95% CI : 1.08-1.51), and sleep duration (>9 h) with the Late-sleep/Late-rise category ( OR  = 1.41, 95% CI : 1.14-1.75) increased the prevalence of dyslipidemia. Accordingly, our results indicate that delayed sleep timing and longer night sleep duration had independent and joint effects on higher risks of dyslipidemia in rural population.