Melatonin as a Biomarker of Circadian Dysregulation
- 1Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center; and 2Department of Epidemiology, School of Public Health and Community Medicine, University of Washington, Seattle, Washington
- Requests for reprints:
Dana K. Mirick, Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, M4-A830, P.O. Box 19024, Seattle, WA 98109-1024. Phone: 206-667-4657; Fax: 206-667-2683. E-mail: dmirick{at}fhcrc.org
Abstract
It would be most useful to identify a biomarker of circadian dysregulation that could be used in epidemiologic studies of the effects of circadian disruption in humans. An indicator of circulating melatonin level has been shown to be a good biomarker of circadian dysregulation and has been associated with nightshift work and exposure to light-at-night in both laboratory-based and field studies. Among other circadian markers (such as core body temperature), it remains comparatively robust in the presence of various external influences. It can be reliably measured directly and indirectly through its metabolites in urine, blood, and saliva. Urinary melatonin has been shown to be stable over time, making it useful in epidemiologic studies in which laboratory processing is not immediately available, as well as studies of cancer with long latency periods. Several studies have shown melatonin to be useful in measuring diurnal type, which is of increasing interest as it becomes more apparent that successful adaptation to shift work may be dependent on diurnal preference. (Cancer Epidemiol Biomarkers Prev 2008;17(12):3306–13)
Footnotes
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- Accepted September 26, 2008.
- Received July 3, 2008.
- Revision received September 18, 2008.
