title: Risk of lung cancer in relation to contiguous windows of endotoxin exposure among female textile workers in Shanghai.
abstract: OBJECTIVE
  Exposure to endotoxin has been consistently associated with a reduced risk of lung cancer. However, there is a paucity of information regarding temporal aspects of this relationship. The objective of this study was to investigate the associations between contiguous windows of endotoxin exposure and risk of lung cancer.
  
  
  METHODS
  Data were reanalyzed from a case-cohort study (602 cases, 3,038 subcohort) of female textile workers in Shanghai, China. Cumulative endotoxin exposure was partitioned into two windows: ≥20 and <20 years before risk. Exposure-response relations were examined using categorical and non-linear (semi-parametric) models, accounting for confounding by previous exposure windows.
  
  
  RESULTS
  There was an inverse trend of decreasing risk of lung cancer associated with increasing levels of endotoxin exposure ≥20 years before risk (p trend = 0.02). Women in the highest two categories of cumulative exposures had hazard ratios of 0.78 (95% CI 0.60-1.03) and 0.77 (95% CI 0.58-1.02) for lung cancer, respectively, in comparison with unexposed textile workers. There was, however, a weaker association and not statistically significant between lung cancer and endotoxin exposure accumulated in the more recent window (<20 years before risk).
  
  
  CONCLUSIONS
  Results provide further evidence that endotoxin exposure that occurred 20 years or more before risk confers the strongest protection against lung cancer, indicating a possible early anti-carcinogenic effect. Further studies are needed to better understand the underlying biological mechanisms for this effect.
authors: Department of Epidemiology and Population Health, Albert Einstein College of Medicine, 1300 Morris Park Ave., Belfer Bldg Room 1315-B, Bronx, NY, USA. ilir.agalliu@einstein.yu.edu
authors: Ilir
authors: I
authors: Agalliu
authors: Sadie
authors: S
authors: Costello
authors: Katie M
authors: KM
authors: Applebaum
authors: Roberta M
authors: RM
authors: Ray
authors: George
authors: G
authors: Astrakianakis
authors: Dao Li
authors: DL
authors: Gao
authors: David B
authors: DB
authors: Thomas
authors: Harvey
authors: H
authors: Checkoway
authors: Ellen A
authors: EA
authors: Eisen
mesh_terms: D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D004731:Endotoxins / Q000506:poisoning*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D008875:Middle Aged; D017711:Nonlinear Dynamics; D009784:Occupational Diseases / Q000139:chemically induced / Q000453:epidemiology*; D016273:Occupational Exposure; D012307:Risk Factors; D013783:Textile Industry; D013784:Textiles / Q000382:microbiology
chemical_list: D004731:Endotoxins