Impact of sleep habits on life expectancy free of cardiovascular disease in the Chinese population: a prospective cohort study

BACKGROUND: Little is known about how sleep problems affect total life expectancy (LE) and LE free of cardiovascular disease (CVD) and its subtypes. METHODS: We included 483384 adults from the China Kadoorie Biobank. Sleep duration was categorized as <6 hours per day (h/d), 6-9 h/d, and >9 h/d. Sleep disturbance was defined as having at least one of the following: self-reported difficulties initiating and maintaining sleep, early morning awakening, and daytime dysfunction. We estimated sex-specific LE with and without CVD at age 40 by using multistate Markov models, with separate models specified for total CVD, ischemic heart disease, ischemic stroke, and hemorrhagic stroke as the disease state. RESULTS: During a median follow-up of 12.1 years, we documented 135429 incident CVD events and 48372 deaths. Longer sleep duration (>9 h/d) had the greatest impact on total LE and LE free of CVD and its subtypes, with the impact on total LE greater than that of disease-free LE. At age 40, total LE and LE without CVD were reduced by 2.11 and 1.29 years in men, and 1.37 and 0.43 years in women, respectively. In contrast, sleep disturbance mainly reduced disease-free LE, reducing the proportion of life spent healthy; compared with those without sleep disturbance, men and women had 0.46 and 0.22 years lower total LE, and 0.99 and 1.05 years lower LE without CVD. CONCLUSIONS: Abnormal sleep duration, especially long sleep, and sleep disturbance were linked with lower total LE and LE free of CVD in this Chinese population, highlighting the importance of good sleep habits.