title: Night shift work and lung cancer risk among female textile workers in Shanghai, China.
abstract: In 2007, the International Agency for Research on Cancer classified shift work that involves circadian disruption as a probable human carcinogen. Suppression of the anti-neoplastic hormone, melatonin, is a presumed mechanism of action. We conducted a case-cohort study nested within a cohort of 267,400 female textile workers in Shanghai, China. Newly diagnosed lung cancer cases (n = 1451) identified during the study period (1989-2006) were compared with an age-stratified subcohort (n = 3040). Adjusting for age, smoking, parity, and endotoxin exposure, relative risks [hazard ratios (HRs)] were estimated by Cox regression modeling to assess associations with cumulative years and nights of rotating shift work. Results did not consistently reveal any increased risk of lung cancer among rotating shift work or statistically significant trends for both cumulative years (HR 0.82, 95% CI 0.66 to 1.02; P(trend) = 0.294) and nights (HR 0.81, 95% CI 0.65 to 1.00; P(trend) = 0.415). Further analyses imposing 10- and 20-year lag times for disease latency also revealed similar results. Contrary to the initial hypothesis, rotating nighttime shift work appears to be associated with a relatively reduced lung cancer risk although the magnitude of the effect was modest and not statistically significant.
authors.affiliation: a Department of Preventive Medicine, Bassett Army Community Hospital , Fort Wainwright , Alaska.
authors.forename: Paul
authors.initials: P
authors.lastname: Kwon
authors.forename: Jessica
authors.initials: J
authors.lastname: Lundin
authors.forename: Wenjin
authors.initials: W
authors.lastname: Li
authors.forename: Roberta
authors.initials: R
authors.lastname: Ray
authors.forename: Christopher
authors.initials: C
authors.lastname: Littell
authors.forename: Daoli
authors.initials: D
authors.lastname: Gao
authors.forename: David B
authors.initials: DB
authors.lastname: Thomas
authors.forename: Harvey
authors.initials: H
authors.lastname: Checkoway
mesh_terms: D000328:Adult; D000368:Aged; D002681:China / Q000453:epidemiology; D002940:Circadian Rhythm; D015331:Cohort Studies; D004731:Endotoxins / Q000633:toxicity; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000209:etiology; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013783:Textile Industry; D014940:Work Schedule Tolerance
chemical_list: D004731:Endotoxins
keywords: Chinese female; lung cancer; night shift; shift work; textile workers