0434 Shift-work and cancer research: developing a quantitative approach to assess chronodisruption
本文指出以往倒班工作与癌症关系的研究忽略了个人生物钟类型和倒班之外的活动时间，可能导致错误结论，并提出一种定量评估昼夜节律紊乱的方法来改进未来研究。
<h3>Objectives</h3> In 2007, IARC classified shift-work involving “circadian disruption” as probably carcinogenic [Group 2A]. Thereafter, 23 shift-work studies into a series of malignant endpoints provided additional epidemiologic evidence regarding chains of cancer causation, which appear biologically plausible when experimental data are considered. Since none of the studies specifically assessed “circadian disruption” or disturbed chronobiology, we ask the following: Does published research suffer from chronobiological errors? How could we assess circadian or chronodisruption [CD] in future epidemiological studies? <h3>Method</h3> On the basis of chronobiological insights we develop a quantitative approach to assess CD for different chronotypes and for different shift-work regimens. We examine how chronobiological errors may have affected studies published so far with a focus on those which considered chronobiological information but were confined to night-work. <h3>Results</h3> We illustrate that ignoring “internal time”, which is critically determined by an individual’s chronotype, may lead to what we propose to call “IT errors”. In addition, assessing biological effects associated with shift-work should also include <i>associated </i>activities and therefore temporal information beyond the nominal shift time. Such errors of truncating relevant “external time” information (activities at chronobiologically unusual times start before and do not end with the shift) we propose to coin “ET errors”. We propose methodologically <i>how</i> observational research may avoid potential chronobiological biases and <i>how</i> chronodisruption can be computed. <h3>Conclusions</h3> Avoiding both IT and ET errors with regard to <i>any</i> – and not just night – shift work may be a prerequisite to assess causal links between shift-work and cancer which may remain otherwise masked.