Association between sleep duration, sleep quality and hyperlipidemia in middle-aged and older Chinese: The Dongfeng-Tongji Cohort Study

Aims This study aimed to evaluate the relationship between sleep duration, sleep quality and hyperlipidemia in middle-aged and older Chinese. Methods We included 20,712 individuals at baseline from September 2008 to June 2010, and they were followed-up until October 2013. Hyperlipidemia was defined according to the Chinese guidelines on the prevention and treatment of dyslipidemia in adults. Sleep duration was self-reported and sleep quality was evaluated with a questionnaire that was designed according to the Pittsburgh Sleep Quality Index. Logistic regression and Cox proportional hazard models were conducted to explore the associations. Results In the cross-sectional analyses, longer sleep duration (>= 10 h) was significantly associated with higher prevalence of hyperlipidemia (odds ratio (OR) = 1.17, 95% confidence interval (CI) = 1.02-1.35) after adjusting for potential confounders. The ORs of hyperlipidemia were significantly elevated among participants with impaired sleep quality (OR = 1.14, 95% CI = 1.08-1.22) and poor sleep quality (OR = 1.20, 95% CI = 1.08-1.34) when compared to those with good sleep quality. In the longitudinal analyses, compared to participants with a sleep duration of 7-<8 h, those with a sleep duration of 9-<10 h (hazard ratio (HR) = 1.19, 95% CI = 1.04-1.35) and >= 10 h (HR = 1.27, 95% CI = 1.02-1.58) showed significantly higher risk of hyperlipidemia after adjusting for potential confounders. However, no statistically significant association was found between impaired or poor sleep quality and hyperlipidemia. Conclusions Longer sleep duration was significantly associated with higher risk of hyperlipidemia. Impaired or poor sleep quality were associated with elevated prevalence of hyperlipidemia, but not with the incidence of hyperlipidemia.