中文摘要：

目的 描述中国慢性病前瞻性研究（CKB）项目人群的睡眠时长、午睡习惯与失眠症状的人群分布，并分析睡眠因素之间的关联。方法 采用自行设计的电子问卷进行面对面基线调查，收集调查对象人口社会学特征、生活方式等信息。剔除患有冠心病、脑卒中、COPD或恶性肿瘤的个体后，共有452 829名30～79岁的研究对象纳入分析。描述不同人群调整性别、年龄、地区后的睡眠因素的分布特征；并分性别使用logistic回归分析睡眠因素间的关联。结果 研究对象平均每天睡眠时长为7.41 h；20.3%的研究对象一年四季均有午睡习惯，40.1%仅在夏季午睡，39.6%没有午睡习惯；研究对象自报“入睡困难”、“早醒”、“日间功能障碍”频率分别为11.0%、10.0%和2.1%。不同性别、年龄、地区、受教育程度、家庭年收入和婚姻状况人群的睡眠因素分布差异有统计学意义（P〈 0.05）。随着睡眠时长的增加，失眠症状风险整体呈下降趋势（线性趋势检验P〈 0.001）；没有午睡习惯者其入睡困难、早醒的风险更高（P〈 0.05）；睡眠时间越长的人群中，有午睡习惯者所占比例越大（P〈 0.05）。结论 不同社会人口学特征人群的睡眠时长、午睡习惯与失眠症状分布存在差异，睡眠因素之间也存在关联，故应在睡眠干预或临床诊疗中针对不同人群制定相应策略，并将睡眠因素综合考虑。

英文摘要：

Objective To investigate the distribution of sleep duration, daytime naps habits,and insomnia-related symptoms among participants from the China Kadoorie Biobank （CKB） study,and to examine the associations between the sleep-associated factors. Methods A self-designed computer-based questionnaire was adopted to collect social-demographic information and lifestyle-related factors of the participants. A total of 452 829 Chinese adults aged 30-79 years, without self-reported histories of coronary heart disease, stroke, chronic obstructive pulmonary diseases or cancer, were included in this study. General linear regression and multinomial logistic regression models were used to estimate the distributions on duration of sleep, daytime naps habits, and insomnia-related symptoms in different populations, after adjusted for gender, age, and residential regions. Gender-specific logistic regression model was adopted to examine the associations between the above mentioned sleep-related factors. Results The average sleep duration of the participants was 7.41 hours per day, with 20.3% of them having daytime naps all year round, but 40.1% only had daytime naps in summer, and 39.6% had no habits of daytime naps. 11.0%, 10.0%, and 2.1% of the participants reported having had symptoms as difficulty in falling asleep, waking up too early or with daytime dysfunction, respectively. There were significant differences on the distributions in sleep-related factors between participants with different gender, age, residential areas, education levels,household income, and marital status （P〈 0.05）. Results from the logistic regression showed that longer sleep duration was associated with lower risks of insomnia-related symptoms trend （P〈 0.001）. Factor as without habits of daytime naps seemed to be associated with higher risks of insomnia-related symptoms （P〈 0.05）. Participants with longer sleep duration were more likely to have the habit of taking daytime naps （P〈 0.05）. Conclusions The distributions of sleep d