title: Effects of asbestos and smoking on gas diffusion in people exposed to crocidolite.
abstract: OBJECTIVE
  To examine the effects of asbestos exposure and tobacco smoking on the level and rate of change of the diffusing capacity of the lung for carbon monoxide (DLCO).
  
  
  METHODS
  A cohort study of 934 people (including both mine workers and town residents) exposed to crocidolite (blue asbestos) at the asbestos mines and in the town of Wittenoom, Western Australia, between 1943 and 1966. DLCO measurements were taken during a follow-up period from 1992 to 2002.
  
  
  METHODS
  Baseline levels of DLCO and change in levels over time.
  
  
  RESULTS
  2980 DLCO measurements were done on 934 people (of whom 818 were men and 724 were workers) who underwent a median of 2 (range, 1-17) measurements during the follow-up period. Radiographic asbestosis at baseline and asbestos exposure at a younger age were associated with lower DLCO values. The average rate of decline in DLCO was 0.33 (95% CI, 0.31-0.35) units per year, plus an additional decrement of 0.22 (95% CI, 0.12-0.32) units per year if the participant had radiographic asbestosis at the beginning of the follow-up period. Compared with never-smokers, current smokers and ex-smokers had lower DLCO at baseline, but smoking status did not affect the change in DLCO during the follow-up period.
  
  
  CONCLUSIONS
  Our results confirm a continuous deleterious effect of crocidolite on DLCO, especially on people with asbestosis. Smoking was associated with lower DLCO levels, but was not a significant predictor of rate of change in DLCO. Smoking status did not affect the relationships between crocidolite exposure and the level or rate of change of DLCO in this population.
authors.affiliation: School of Public Health, Curtin University of Technology, Kent Street, Bentley, WA 6102, Australia. h.alfonso@curtin.edu.au
authors.forename: Helman S
authors.initials: HS
authors.lastname: Alfonso
authors.forename: Lin
authors.initials: L
authors.lastname: Fritschi
authors.forename: Nicholas H
authors.initials: NH
authors.lastname: de Klerk
authors.forename: Nola
authors.initials: N
authors.lastname: Olsen
authors.forename: Jan
authors.initials: J
authors.lastname: Sleith
authors.forename: Arthur Bill W
authors.initials: AB
authors.lastname: Musk
mesh_terms: D017677:Age Distribution; D017638:Asbestos, Crocidolite / Q000633:toxicity*; D002248:Carbon Monoxide / Q000493:pharmacokinetics*; D015331:Cohort Studies; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D062665:Epidemiological Monitoring; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008168:Lung / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011653:Pulmonary Diffusing Capacity / Q000187:drug effects*; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology / Q000378:metabolism*; D016540:Smoking Cessation / Q000706:statistics & numerical data; D014904:Western Australia / Q000453:epidemiology
chemical_list: D017638:Asbestos, Crocidolite; D002248:Carbon Monoxide