Ss58-03 Shift Work and Chronic Disease Risk: Biological Mechanisms and Adaptation

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Introduction Shift work increases the risk of chronic diseases, however mechanisms explaining the increased risks, and whether an individual’s ability to adapt to their shift schedule may alter disease risk, are still largely undetermined. This presentation will provide a brief overview of recent mechanistic studies among rotating night shift workers; the role of adaptation to shift work will also be discussed. Materials and Methods Data from the HORMONIT study will be used. This study included 51 male, rotating shift workers from the automotive industry in Barcelona, Spain, sampled twice at the end of a 3-week night-shift (22:00-06:00 hrs) and 3-week day-shift (06:00-14:00 hrs) rotation. Participants collected urine voids over 24-hours, gave blood twice, wore several sensors, and responded to questionnaires during each shift. We examined the levels of several hormones (including aMT6s, the major metabolite of melatonin), cytokines and metabolomic markers. By comparing aMT6s production and sleep periods, we evaluated adaptation to shift work. Results We found evidence that melatonin and sex steroid hormones, cytokines, and metabolomic markers were perturbed during night shift work. These are related to hormone-dependent cancers (breast, prostate) and other chronic diseases. We identified several variables associated with the ability to adapt to a slow rotating shift schedule using a central circadian biomarker-based approach. However, peripheral rhythms did not necessarily show signs of synchronization. Conclusions These findings provide new evidence linking night shift work to chronic disease. While adaptation may be beneficial for reducing chronic disease risk, it likely depends on the type of shift schedule and speed of rotation.