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Nomination Summary for shift work at night, artificial light at night and circadian disruption (N21801)

Nominated Substances: No Specific Substances or Agents are Selected for this Nomination

Nomination Date: 10/17/2017

Nominator: NIEHS

Rationale: Many people experience interruptions in light-dark cycles due to their lifestyle choices (e.g. use of electronic devices at night), location of their residences (e.g., urban light pollution), or working at night (e.g., shift work). Exposures to light at night (LAN) or changes in the timing of exposures to natural light (such as with ‘jet lag’) may disrupt biological processes controlled by endogenous circadian rhythms, potentially resulting in adverse health outcomes. LAN was nominated to both the NTP’s Office of the Report on Carcinogens (ORoC) and Office of Health Assessment and Translation (OHAT) to evaluate health effects. OHAT and ORoC convened a workshop, which included 12 panelists on shift work at night, light at night and circadian disruption on March 10-11, 2016 to obtain external scientific input on topics important for informing the literature-based health hazard assessments including strategies for integrating data across evidence streams and exposure scenarios, and on data gaps and research needs. See for information on the workshop and Lunn et al. 2017 for the workshop report. ORoC is evaluating LAN/shift work related to circadian disruption for possible listing in the RoC. More information on the RoC review is available at The workshop report includes the following research needs for the field specifically related to animal models: • Conduct studies in animals to model relevant components of shift-work exposure on biomarkers of circadian function and health outcomes. • Conduct studies in animals that involve both acute and chronic repeated phase shifts in the light-dark cycle, exposure to constant light, feeding at the “wrong” time of day, and acutely or chronically shortened sleep. Such studies have the potential to elucidate mechanisms by which disrupted sleep or circadian rhythms lead to adverse health outcomes, and for the exploitation of these models for testing therapeutic interventions. • Conduct studies in animalswith dimLANat lower light levels, and use diurnalmodels tomore closely replicate human exposures and effects. • Evaluate interactions between chemical and light exposures in humans and animals.

NTP Principles: not specified