Table_1_Sleeping Late Increases the Risk of Myocardial Infarction in the Middle-Aged and Older Populations.docx

Objective: Sleep has a significant influence on the incidence of myocardial infarction (MI). The purpose of this study was to investigate the association between sleep timing including bedtime, wake-up time and sleep midpoint, and the incidence of MI.
Methods: A total of 4,576 patients (2,065 men, 2,511 women; age 63.4 ± 11.0 years) were selected from the Sleep Heart Health Study. Sleep timings on weekdays and weekends were recorded or calculated based on the sleep habits questionnaire completed by the participants at baseline. Bedtime was divided into 10:00 PM and before, 10:01 PM−11:00 PM, 11:01 PM−12:00 AM, and later than 12:00 AM. Cox proportional hazards regression analysis was used to examine the relationship between sleep timings and MI.
Results: Participants with a weekday bedtime later than 12:00 AM, between 11:01 PM−12:00 AM, and 10:00 PM or before had a higher incidence of MI than those with a bedtime between 10:01 PM and 11:00 PM (9.2% vs. 7.0% vs. 6.9% vs. 5.1%, respectively; P = 0.008). Multivariable Cox regression analysis showed that sleeping on weekdays later than 12:00 AM was associated with an increased risk of incident MI after adjusting for potential covariates (hazard ratio, 1.628; 95% confidence interval, 1.092–2.427; P = 0.017). However, there was no significant association between late bedtime on weekends and MI. In addition, no significant association of late wake-up time and delayed sleep midpoint on both weekdays and weekends with the incidence of MI was observed.
Conclusion: Sleeping late on weekday (>12:00 AM) independently increased the risk of MI. This finding emphasizes the importance of a proper bedtime for the maintenance of the health of the cardiovascular system.

研究目的：睡眠对心肌梗死（myocardial infarction, MI）的发生风险具有显著影响。本研究旨在探讨包括就寝时间、醒来时间及睡眠中点在内的睡眠定时与心肌梗死发生风险之间的关联。
研究方法：本研究从睡眠心脏健康研究（Sleep Heart Health Study）中纳入了4576名受试者（男性2065名，女性2511名；年龄63.4±11.0岁）。基于受试者在基线时完成的睡眠习惯调查问卷，记录或计算其工作日与周末的睡眠定时情况。将就寝时间划分为以下组别：22:00及更早、22:01~23:00、23:01~00:00以及00:00之后。采用Cox比例风险回归分析（Cox proportional hazards regression analysis）检验睡眠定时与心肌梗死之间的关联。
研究结果：与就寝时间处于22:01~23:00的受试者相比，工作日就寝时间晚于00:00、23:01~00:00以及22:00及更早的受试者，其心肌梗死发生率更高（分别为9.2%、7.0%、6.9%与5.1%；P=0.008）。多变量Cox回归分析（multivariable Cox regression analysis）结果显示，在校正潜在协变量（covariates）后，工作日就寝时间晚于00:00与心肌梗死发生风险升高显著相关（风险比（hazard ratio）=1.628；95%置信区间（confidence interval）：1.092~2.427；P=0.017）。然而，周末就寝较晚与心肌梗死之间未发现显著关联。此外，无论工作日还是周末，醒来时间过晚及睡眠中点延迟均与心肌梗死发生率无显著关联。
研究结论：工作日晚睡（>00:00）会独立增加心肌梗死的发生风险。该发现强调了保持规律就寝时间对维护心血管系统健康的重要性。