title: A 37-year observation of mortality in Chinese chrysotile asbestos workers.
abstract: OBJECTIVE
  This 37-year prospective cohort study was undertaken to provide additional evidence for mortality risks associated with exposure to chrysotile asbestos.
  
  
  METHODS
  577 asbestos workers and 435 control workers in original cohorts were followed from 1972 to 2008, achieving a follow-up rate of 99% and 73%, respectively. Morality rates were determined based on person-years of observation. Cox proportional hazard models were constructed to estimate HRs of cause-specific mortality, while taking into account age, smoking and asbestos exposure level.
  
  
  RESULTS
  There were 259 (45%) deaths identified in the asbestos cohort, and 96 died of all cancers. Lung cancer (n=53) and non-malignant respiratory diseases (n=81) were major cause-specific deaths, in contrast to nine lung cancers and 11 respiratory diseases in the controls. Age and smoking-adjusted HRs for mortality by all causes and all cancers in asbestos workers were 2.05 (95% CI 1.56 to 2.68) and 1.89 (1.25 to 2.87), respectively. The risks for lung cancer and respiratory disease deaths in asbestos workers were over threefold that in the controls (HR 3.31(95% CI 1.60 to 6.87); HR 3.23 (95% CI 1.68 to 6.22), respectively). There was a clear exposure-response trend with asbestos exposure level and lung cancer mortality in both smokers and non-smokers.
  
  
  CONCLUSIONS
  Data from this prospective cohort provide strong evidence for increased mortality risks, particularly from lung cancer and non-malignant respiratory diseases, associated with exposure to chrysotile asbestos, while taking into account of the smoking effect.
authors.affiliation: Division of Occupational and Environmental Health, School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China. xrwang@cuhk.edu.hk
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Wang
authors.forename: Eiji
authors.initials: E
authors.lastname: Yano
authors.forename: Hong
authors.initials: H
authors.lastname: Qiu
authors.forename: Ignatius
authors.initials: I
authors.lastname: Yu
authors.forename: Midori N
authors.initials: MN
authors.lastname: Courtice
authors.forename: L A
authors.initials: LA
authors.lastname: Tse
authors.forename: Sihao
authors.initials: S
authors.lastname: Lin
authors.forename: Mianzhen
authors.initials: M
authors.lastname: Wang
mesh_terms: D000328:Adult; D017632:Asbestos, Serpentine / Q000009:adverse effects* / Q000032:analysis; D002681:China / Q000453:epidemiology; D004812:Epidemiologic Methods; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology / Q000401:mortality; D008297:Male; D009784:Occupational Diseases / Q000209:etiology* / Q000401:mortality; D016273:Occupational Exposure / Q000009:adverse effects / Q000032:analysis; D012140:Respiratory Tract Diseases / Q000209:etiology* / Q000401:mortality; D012907:Smoking / Q000009:adverse effects / Q000401:mortality
chemical_list: D017632:Asbestos, Serpentine