Xue Li1, Xiuyu Pang2, Zhipeng Liu2, Qiao Zhang2, Changhao Sun2, Jianjun Yang3, Ying Li4. 1. College of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China. 2. Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, 150081, China. 3. The School of Public Health & Management, Ningxia Medical University, Ningxia, China. Electronic address: Yangjj@nxmu.edu.cn. 4. Department of Nutrition and Food Hygiene, College of Public Health, Harbin Medical University, Harbin, 150081, China. Electronic address: liying_helen@163.com.
Abstract
BACKGROUND: The joint effect of daytime naps and night sleep on the risk of stroke has not been clarified. Our research aimed to verify this relationship based on data from a large sample-sized cross-sectional study and a cohort study. METHODS: The cross-sectional study included 7887 subjects, aged 20-74 years. Using stratified random sampling, 1928 individuals were selected for the cohort study. We then followed up with these individuals for an average of 4.94 years and collected detailed sleep information with the Pittsburgh Sleep Quality Index (PSQI). Serum fasting blood glucose, triglyceride, cholesterol and high density lipoprotein were analyzed, and anthropometric measurements were taken. Interaction and joint analyses were performed. RESULTS: Consistent with the results in the cross-sectional study, hazard ratios (HRs) (95% CI) of stroke were 1.94 (1.21-3.13) and 2.24 (1.05-4.79) for daytime napping ≥1 h and nighttime sleeping ≥9 h in the cohort study. For no naps combined with <7 h of nighttime sleeping, the HR (95%CI) was 2.61 (1.17-5.82). For ≥1 h of naps combined with <7 h, 7-8 h, 8-9 h, and ≥9 h of nighttime sleeping, HRs (95% CI) were 2.16 (1.03-4.51), 2.36 (1.07-5.20), 2.41 (1.11-5.20) and 3.37 (1.05-10.81), respectively. CONCLUSIONS: Individuals with 7-8 h of night sleep combined with no daytime naps or less than 1 h of daytime napping were at low risk of stroke; nighttime sleeping ≥9 h combined with daytime napping ≥1 h and night sleep <7 h combined with 0 or >1 h daytime napping was associated with high risk of stroke. CLINICAL TRIAL REGISTRY: http://www.chictr.org. TRAIL NUMBER: ChiCTR-ECH-1200272, ChiCTR-ECH-12002938.
BACKGROUND: The joint effect of daytime naps and night sleep on the risk of stroke has not been clarified. Our research aimed to verify this relationship based on data from a large sample-sized cross-sectional study and a cohort study. METHODS: The cross-sectional study included 7887 subjects, aged 20-74 years. Using stratified random sampling, 1928 individuals were selected for the cohort study. We then followed up with these individuals for an average of 4.94 years and collected detailed sleep information with the Pittsburgh Sleep Quality Index (PSQI). Serum fasting blood glucose, triglyceride, cholesterol and high density lipoprotein were analyzed, and anthropometric measurements were taken. Interaction and joint analyses were performed. RESULTS: Consistent with the results in the cross-sectional study, hazard ratios (HRs) (95% CI) of stroke were 1.94 (1.21-3.13) and 2.24 (1.05-4.79) for daytime napping ≥1 h and nighttime sleeping ≥9 h in the cohort study. For no naps combined with <7 h of nighttime sleeping, the HR (95%CI) was 2.61 (1.17-5.82). For ≥1 h of naps combined with <7 h, 7-8 h, 8-9 h, and ≥9 h of nighttime sleeping, HRs (95% CI) were 2.16 (1.03-4.51), 2.36 (1.07-5.20), 2.41 (1.11-5.20) and 3.37 (1.05-10.81), respectively. CONCLUSIONS: Individuals with 7-8 h of night sleep combined with no daytime naps or less than 1 h of daytime napping were at low risk of stroke; nighttime sleeping ≥9 h combined with daytime napping ≥1 h and night sleep <7 h combined with 0 or >1 h daytime napping was associated with high risk of stroke. CLINICAL TRIAL REGISTRY: http://www.chictr.org. TRAIL NUMBER: ChiCTR-ECH-1200272, ChiCTR-ECH-12002938.