Rotating night-shift work and lung cancer risk among female nurses in the United States

Am J Epidemiol. 2013 Nov 1;178(9):1434-41. doi: 10.1093/aje/kwt155. Epub 2013 Sep 18.


The risk of lung cancer among night-shift workers is unknown. Over 20 years of follow-up (1988-2008), we documented 1,455 incident lung cancers among 78,612 women in the Nurses' Health Study. To examine the relationship between rotating night-shift work and lung cancer risk, we used multivariate Cox proportional hazard models adjusted for detailed smoking characteristics and other risk factors. We observed a 28% increased risk of lung cancer among women with 15 or more years spent working rotating night shifts (multivariate relative risk (RR) = 1.28, 95% confidence interval (CI): 1.07, 1.53; Ptrend = 0.03) compared with women who did not work any night shifts. This association was strongest for small-cell lung carcinomas (multivariate RR = 1.56, 95% CI: 0.99, 2.47; Ptrend = 0.03) and was not observed for adenocarcinomas of the lung (multivariate RR = 0.91, 95% CI: 0.67, 1.24; Ptrend = 0.40). Further, the increased risk associated with 15 or more years of rotating night-shift work was limited to current smokers (RR = 1.61, 95% CI: 1.21, 2.13; Ptrend < 0.001), with no association seen in nonsmokers (Pinteraction = 0.03). These results suggest that there are modestly increased risks of lung cancer associated with extended periods of night-shift work among smokers but not among nonsmokers. Though it is possible that this observation was residually confounded by smoking, our findings could also provide evidence of circadian disruption as a "second hit" in the etiology of smoking-related lung tumors.

Keywords: circadian disruption; lung cancer; night work; rotating shift work; smoking.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Age Factors
  • Body Mass Index
  • Female
  • Health Behavior
  • Humans
  • Life Style
  • Lung Neoplasms / epidemiology*
  • Lung Neoplasms / pathology
  • Middle Aged
  • Nurses / statistics & numerical data*
  • Occupational Diseases / epidemiology*
  • Occupational Diseases / pathology
  • Occupational Exposure
  • Occupational Health
  • Risk Factors
  • Smoking / epidemiology*
  • Time Factors
  • United States / epidemiology
  • Work Schedule Tolerance*