BACKGROUND Night work has been associated with coronary heart disease. The present study examined exposure-response relations between quantitative night work characteristics and coronary heart disease (angina pectoris or myocardial infarction) with the aim to contribute to evidence-based recommendations for low-risk night work schedules. METHODS We followed 100 149 night workers (80% women) and 153 882 day workers (78% women), all health care workers in Denmark with day by day payroll information on night shifts from 2007 to 2015. We analysed data with Poisson regression stratified by sex and adjusted for age, calendar year, diabetes, family history of cardiovascular disease, educational level, occupation, indicators for obesity, hypercholesterolaemia, and hypertension. RESULTS Female and male night workers worked on average 1.7 and 1.8 night shifts per month for an average duration of less than 4 years. During follow-up, 1198 night and 2128 day workers were hospitalized with first-time coronary heart disease. When compared with day workers, the overall incidence rate ratios for female and male night workers were 1.06 [95% confidence interval (CI): 0.97, 1.17] and 1.22 (95% CI 1.07, 1.39). Highest risks were observed in top exposure categories for several night work characteristics. However, no consistent exposure-response relations by number of monthly night shifts, cumulative night shifts, years with rotating night shifts, years with any night shift and consecutive night shifts were observed among the night workers of either sex. CONCLUSIONS This study of a population with low exposure to night work does not indicate that reducing extent of monthly night shifts, cumulative night shifts, years with rotating night shifts, years with any night shift and consecutive night shifts would reduce the risk of coronary heart disease.

中文翻译：

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医护人员夜班工作特征和冠心病发生风险：全国队列研究。

背景技术夜间工作与冠心病有关。本研究检查了定量夜间工作特征与冠心病（心绞痛或心肌梗塞）之间的暴露-反应关系，旨在为低风险夜间工作时间表提供基于证据的建议。方法 我们对 100 149 名夜班工人（80% 为女性）和 153 882 名日班工人（78% 为女性）进行了跟踪调查，他们都是丹麦的卫生保健工作者，并掌握了 2007 年至 2015 年夜班的每日工资单信息。我们使用泊松回归分层分析了数据。按性别分类，并根据年龄、历年、糖尿病、心血管疾病家族史、教育水平、职业、肥胖指标、高胆固醇血症和高血压进行调整。结果 女性和男性夜班工人平均每月工作 1.7 次和 1.8 次夜班，平均工作时间不到 4 年。随访期间，1198 名夜间工人和 2128 名白天工人因首次冠心病住院。与日班工人相比，女性和男性夜班工人的总体发病率比率分别为1.06[95%置信区间(CI)：0.97，1.17]和1.22(95% CI 1.07，1.39)。在几个夜间工作特征的最高暴露类别中观察到最高风险。然而，在两种性别的夜班工人中，没有观察到每月夜班次数、累积夜班次数、轮换夜班年数、任何夜班年数和连续夜班年数之间一致的暴露-反应关系。结论 这项针对夜间工作时间较少的人群的研究并不表明，减少每月夜班的程度、累计夜班、轮换夜班的年数、任何夜班的年数和连续夜班的程度会降低冠心病的风险。