Novel Circadian Exposure Metrics for Shift Workers

 描述(申请人提供)：倒班工作是慢性病风险的预测指标。然而，到目前为止，影响健康所需的倒班工作暴露的临界剂量仍然不清楚。我们寻求开发改进的暴露指标，以更好地捕捉与工作时间表，特别是倒班工作有关的职业压力。其中一个因素被认为是 倒班工作和不利的健康后果之间的联系是工作时间对个人生理和行为的24小时节律的干扰：因为活动、食物摄取和光照发生在不适当的生物时间(即在个人生物夜晚)工作时间表会导致一定程度的昼夜紧张(或干扰)。然而，就睡眠时间和清醒行为而言，24小时节律表现出很大的个体间变异性；这种变异性也被称为“时型”。例如，早期的时型--如果没有社交的话 和工作限制--往往在24小时内入睡和醒来的时间明显早于较晚的时型。因此，职业昼夜节律紧张不仅取决于工作时间表本身，而且还取决于个人各自的时型，这似乎是合理的。我们的目标是通过开发新的暴露指标来解决这个问题，这些指标依赖于对时型和工作时间表的联合评估，并将它们与BMI联系起来--BMI是慢性病风险的主要中介。在护士健康研究3(NHS3)中，我们实施了非常详细的工作时间表评估。此外，我们还介绍了两种主要的时型测量方法。基于这些措施，我们将开发两个昼夜节律应变度量，最终可以应用于广泛的研究和推广。我们将对这两种时型测量方法和新开发的跨工作时间表的昼夜节律应变测量方法进行系统比较。接下来，我们将把这些指标应用于护士健康研究2和NHS3，以检查职业昼夜节律紧张和体重指数之间的关系，体重指数是一种中心性慢性病媒介，以前在动物和实验研究中与昼夜节律紧张有关。总之，我们试图为个性化的职业风险评估开发广泛适用的指标，反映个性化的昼夜节律压力作为联系倒班工作和不利健康后果的中心生物机制之一。最终，这些新开发的指标可以用于检查与工作时间表相关的昼夜节律压力与健康和安全结果之间的关系，并确定跨行业环境和部门的预防战略的关键剂量。

 DESCRIPTION (provided by applicant): Shift work is a predictor of chronic disease risk. However, to date, the critical dose of exposure to shift work required to impact health remains unclear. We seek to develop improved exposure metrics to better capture the occupational strain linked to work schedules, and, in particular, shift work. One factor thought to underlie the association between shift work and adverse health outcomes is the interference of work times with the individual 24h-rhythm in physiology and behavior: because activity, food intake and light exposure take place at inappropriate biological times (i.e. during the individual biological night) work schedules induce a certain level of circadian strain (or disruption). Yet 24h-rhythms exhibit large inter-individual variability as far as timing of sleep and wake behavior are concerned; this variability is also referred to as "chronotype". For example, early chronotypes - if free of social and work constraints - tend to fall asleep and wake up significantly earlier in the 24h day than late chronotypes. It appears therefore plausible that occupational circadian strain depends not only on the work schedule itself, but also on an individual's respective chronotype. We aim to address this question by developing novel exposure metrics that rely on the conjunct assessment of chronotype and work schedules and linking them to BMI - a prime mediator of chronic disease risk. In the Nurses' Health Study 3 (NHS3), we implemented highly detailed work schedule assessments. In addition, we also introduced the two prime measures of chronotype. Based on these measures, we will develop two circadian strain metrics that, ultimately, could be applied and generalized to a wide range of studies. We will conduct a systematic comparison of the two chronotype measures and the newly developed circadian strain metrics across work schedules. Next, we will apply these metrics to the Nurses' Health Study 2 and NHS3 to examine associations between occupational circadian strain and body mass index, a central chronic disease mediator that has previously been associated with circadian strain in animal and experimental studies. In sum, we seek to develop widely applicable metrics for personalized occupational risk assessment, reflecting personalized circadian strain as one of the central biological mechanisms linking shift work and adverse health outcomes. Ultimately, these newly developed metrics can be used to examine the relationship between work schedule-associated circadian strain and health and safety outcomes, and identify critical doses for prevention strategies, across industry settings and sectors.