CoChat
Sign Up
Cited by 95Circadian rhythm and melatoninSleep and Work-Related FatigueImpact of Light on Environment and Health

Light intensity exposure, sleep duration, physical activity, and biomarkers of melatonin among rotating shift nurses

Grundy, Anne, Sanchez, Maria, Richardson, Harriet, Tranmer, Joan, Borugian, Marilyn, Graham, Charles H., Aronson, Kristan J.·2009·Chronobiology International
DOI 10.3109/07420520903399987
Open this paper in CoChat — free account

Abstract

Long-term, night shiftwork has been identified as a potential carcinogenic risk factor. It is hypothesized that increased light at night exposure during shiftwork reduces melatonin production, which is associated with increased cancer risk. Sleep duration has been hypothesized to influence both melatonin levels and cancer risk, and it has been suggested that sleep duration could be used as a proxy for melatonin production. Finally, physical activity has been shown to reduce cancer risk, and laboratory studies indicate it may influence melatonin levels. A cross-sectional study of light exposure, sleep duration, physical activity, and melatonin levels was conducted among 61 female rotating shift nurses (work schedule: two 12 h days, two 12 h nights, five days off). Light intensity was measured using a light-intensity data logger, and sleep duration and physical activity were self-reported in a study diary and questionnaire. Melatonin concentrations were measured from urine and saliva samples. The characteristics of nurses working day and night shifts were similar. Light intensity was significantly higher during sleep for those working at night (p< 0.0001), while urinary melatonin levels following sleep were significantly higher among those working days (p = 0.0003). Mean sleep duration for nurses working during the day (8.27 h) was significantly longer than for those working at night (4.78 h, p< 0.0001). An inverse association (p = 0.002) between light exposure and urinary melatonin levels was observed; however, this was not significant when stratified by shift group. There was no significant correlation between sleep duration and melatonin, and no consistent relationship between physical activity and melatonin. Analysis of salivary melatonin levels indicated that the circadian rhythms of night workers were not altered, meaning peak melatonin production occurred at night. This study indicates that two nights of rotating shift work may not change the timing of melatonin production to the day among those working at night. Additionally, in this study, sleep duration was not correlated with urinary melatonin levels, suggesting it may not be a good proxy for melatonin production.

Integrity signals

Registry

Crossref · 10.3109/07420520903399987

Cites

51 of 51 references verified0 citation errors · 0 not checkable

Statistics

Recomputing p-values needs the paper’s full text.

Claims the paper makes

This paper’s full text isn’t openly available, so its claims and self-check weren’t run. The registry and citation checks still apply.

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • For nurses, shift work and long work hours are related to adverse health outcomes and indicators of reduced functioning.

    “For nurses, shift work and long work hours have been shown to be related to adverse health outcomes and indicators of reduced functioning.208–217”

    From Sleep, Health, and Society (2017) · cites this paper as [208]

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Related

Authors
Grundy, A., Sanchez, M., Richardson, H., Tranmer, J., Borugian, M., Graham, C. H., & Aronson, K. J.
Affiliations
  • Queen's University (CA)
  • BC Cancer Agency (CA)
Corresponding author
Grundy, Anne
ORCID
Venue
Chronobiology International
Publisher
Informa UK Limited
Published
2009-10
Volume
26
Issue
7
Pages
1443-1461
ISSN
  • 0742-0528 (ISSN-L)
  • 1525-6073
DOI
10.3109/07420520903399987
OpenAlex
W2118958571
Cited by
95
References
50
Citations by year
2026: 1 · 2025: 2 · 2024: 3 · 2023: 9 · 2022: 2 · 2021: 5 · 2020: 2 · 2019: 4 · 2018: 5 · 2017: 6 · 2016: 3 · 2015: 7 · 2014: 6 · 2013: 7 · 2012: 15
FWCI
4.94
Type
journal article
Language
en
Open access
closed
Locations
  • Chronobiology International (publishedVersion)
  • PubMed (publishedVersion)
Funders
Canadian Institutes of Health Research
Topics
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and Work-Related Fatigue
  • Physical Sciences › Environmental Science › Global and Planetary Change › Impact of Light on Environment and Health
Keywords
rotating shifts, night shift nurses, melatonin, urinary melatonin, salivary melatonin, sleep duration, physical activity, circadian rhythm, cancer risk
MeSH terms
Adult, Aged, Circadian Rhythm, Cross-Sectional Studies, Female, Humans, Melatonin, Middle Aged, Motor Activity, Nurses, Surveys and Questionnaires, Saliva, Sleep, Work Schedule Tolerance, Photoperiod

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review