Is there an association among sleep duration, nap, and stroke? Findings from the China Health and Retirement Longitudinal Study

Purpose: The objective of this study was to assess the association among nighttime sleep, daytime napping, total sleep duration (nighttime sleep plus daytime napping), and stroke in an elderly Chinese population. Methods: Data were derived from the 2011 China Health and Retirement Longitudinal Study (CHARLS) with 4785 Chinese respondents over 65 years old. Four binary logistic regression models were used to estimate odds ratios and 95% confidence intervals of the association among total sleep duration, nighttime sleep, daytime napping, and stroke, adjusting for confounders. Results: After controlling for sociodemographic characteristics, lifestyle, health status, and comorbidity, there was no association between abnormal nighttime sleep and stroke (P values > 0.05). Compared to individuals with normal total sleep duration (7–8 h per day), short sleep duration (< 7 h per day) was approximately two times more likely to increase the risk of stroke (AOR = 1.81, 95%CI 1.10–2.97). Individuals who reported vision impairment, disability, hypertension, dyslipidemia, and mental health issues were at higher risk of stroke. In addition, physical activities with different levels were associated with a lower risk of stroke. Taking naps was not associated with stroke incidence (AOR = 1.12, 95%CI 0.77–1.64). Conclusion: In this elderly Chinese population, short total sleep duration per 24 h, not merely daytime napping or nighttime sleep, was significantly associated with an increased risk of stroke. Preventive measures for stroke may require a focus on elderly, sedentary individuals who report other health problems.