title: Racial differences in the association between night shift work and melatonin levels among women.
abstract: Reduced suppression of melatonin in response to working the night shift among people of Asian ancestry has been suggested as a possible explanation for the null results observed in a recent analysis of shift work and breast cancer risk in a Chinese cohort. The authors analyzed the impact of Asian versus white race on previously reported differences in urinary 6-sulfatoxymelatonin levels in a 2003-2008 study in Seattle, Washington, of female health-care workers that exclusively worked night or day shifts. A total of 225 white and 51 Asian participants were included in the analysis. Although 6-sulfatoxymelatonin levels were affected by night shift work in both racial groups, Asian night shift workers consistently showed 6-sulfatoxymelatonin levels that were closer to levels in day shift workers than did white night shift workers. Furthermore, differences in 6-sulfatoxymelatonin levels between white and Asian night shift workers relative to day shift workers were statistically significant in every instance (P < 0.05). These results suggest that Asians may be better able to maintain a "normal" circadian pattern of melatonin production compared with whites and suggest a biological mechanism by which Asian night shift workers may be at a reduced risk of cancer.
authors: Public Health Scienes Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA. pbhatti@fhcrc.org
authors: Parveen
authors: P
authors: Bhatti
authors: Dana K
authors: DK
authors: Mirick
authors: Scott
authors: S
authors: Davis
mesh_terms: D000328:Adult; D001213:Asian; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D016014:Linear Models; D008550:Melatonin / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000652:urine; D008875:Middle Aged; D012890:Sleep / Q000502:physiology*; D044465:White People; D014940:Work Schedule Tolerance / Q000502:physiology*
chemical_list: C054513:6-sulfatoxymelatonin; D008550:Melatonin
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