Rotating night-shift work and lung cancer risk among female nurses in the United States.
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.
Eva S
ES
Schernhammer
Diane
D
Feskanich
Geyu
G
Liang
Jiali
J
Han
D000328:Adult; D000367:Age Factors; D015992:Body Mass Index; D005260:Female; D015438:Health Behavior; D006801:Humans; D008019:Life Style; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000473:pathology; D008875:Middle Aged; D009726:Nurses / Q000706:statistics & numerical data*; D009784:Occupational Diseases / Q000453:epidemiology* / Q000473:pathology; D016273:Occupational Exposure; D016272:Occupational Health; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology*; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D014940:Work Schedule Tolerance
circadian disruption; lung cancer; night work; rotating shift work; smoking