Cited by 214Sleep and Work-Related FatigueCircadian rhythm and melatoninCancer Risks and Factors

Nested case-control study of night shift work and breast cancer risk among women in the Danish military

Hansen, Johnni, Lassen, Christina F·2012·Occupational and Environmental Medicine

Abstract

OBJECTIVES: Growing but limited evidence suggests that night shift work is associated with breast cancer. The authors conducted a nationwide case-control study nested within a cohort of 18,551 female military employees born in 1929-1968 to investigate the risk for breast cancer after night shift work and to explore the role of leisure time sun exposure and diurnal preference. METHODS: The authors documented 218 cases of breast cancer (1990-2003) and selected 899 age-matched controls from the cohort by incidence density sampling. Information on shift work, sun exposure habits, diurnal preference and other potential confounders was obtained from a structured questionnaire. ORs were estimated by multivariate conditional logistic regression. RESULTS: Overall, the authors observed an adjusted OR of 1.4 (95% CI 0.9 to 2.1) among women with ever compared with never night shifts. The RR for breast cancer tended to increase with increasing number of years of night shift work (p=0.03) and with cumulative number of shifts (p=0.02),with a neutral risk for fewer than three night shifts per week. The OR for the group with the highest tertile of cumulative exposure was 2.3 (95% CI 1.2 to 4.6). The most pronounced effect of night shift work on breast cancer risk was observed in women with morning chronotype preference and intense night shifts (OR=3.9, 95% CI 1.6 to 9.5). Night shift workers tended to sunbathe more frequently than day workers. CONCLUSIONS: The results indicate that frequent night shift work increases the risk for breast cancer and suggest a higher risk with longer duration of intense night shifts. Women with morning preference who worked on night shifts tended to have a higher risk than those with evening preference.

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Crossref · 10.1136/oemed-2011-100240

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  • Observational studies consistently suggest positive associations of night shift work with cardiovascular disease and cancer risk.

    “Observational studies consistently suggest positive associations of night shift work and cardiovascular disease (CVD)2 and cancer risk.3-18”

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Authors
Hansen, J., & Lassen, C. F.
Affiliations
Danish Cancer Society (DK)
Corresponding author
Hansen, Johnni
Venue
Occupational and Environmental Medicine
Publisher
BMJ
Published
2012-05-29
Volume
69
Issue
8
Pages
551-556
ISSN
  • 0007-1072 (ISSN-L)
  • 1351-0711
  • 1470-7926
OpenAlex
W2160711420
Cited by
214
References
45
Citations by year
2026: 4 · 2025: 9 · 2024: 9 · 2023: 11 · 2022: 6 · 2021: 12 · 2020: 15 · 2019: 7 · 2018: 26 · 2017: 24 · 2016: 16 · 2015: 21 · 2014: 25 · 2013: 27 · 2012: 2
FWCI
32.14
Type
journal article
Language
en
Open access
closed
Locations
  • Occupational and Environmental Medicine (publishedVersion)
  • PubMed (publishedVersion)
Topics
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and Work-Related Fatigue
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
  • Health Sciences › Medicine › Oncology › Cancer Risks and Factors
Keywords
night shift work, breast cancer risk, women in the military, diurnal preference, chronotype, sunbathing, occupational cancer risk
MeSH terms
Adult, Aged, Aged, 80 and over, Breast Neoplasms, Circadian Rhythm, Denmark, Female, Humans, Middle Aged, Military Personnel, Occupations, Risk Factors, Sunlight, Work, Work Schedule Tolerance, Logistic Models, Odds Ratio, Case-Control Studies

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