title: The influence of dust standards on the prevalence and severity of coal worker's pneumoconiosis at autopsy in the United States of America.
abstract: BACKGROUND
  Coal worker's pneumoconiosis is a major occupational lung disease in the United States. The disease is primarily controlled through reducing dust exposure in coal mines using technological improvements and through the establishment of dust standards by regulatory means.
  
  
  OBJECTIVE
  To determine if dust standards established in the US Federal Coal Mine Health and Safety Act of 1969 have reduced the prevalence and severity of coal worker's pneumoconiosis.
  
  
  METHODS
  The study population included materials from 6103 deceased coal miners submitted to the National Coal Workers' Autopsy Study from 1971 through 1996. Type and severity of coal worker's pneumoconiosis were classified using standardized diagnostic criteria.
  
  
  RESULTS
  Among miners who worked exclusively prior to the 1969 dust standard, 82.6% had coal macules, 46.3% coal nodules, 28.2% silicotic nodules, and 10.3% progressive massive fibrosis. Lower prevalences were noted among miners exposed exclusively to post-1970 dust levels: 58.8% had coal macules, 15.0% coal nodules, 8.0% silicotic nodules, and 1.2% progressive massive fibrosis. The differences in prevalence were highly significant (P < .001) for all types of pneumoconiosis, including progressive massive fibrosis, after adjustment for age, years of mining, and smoking status.
  
  
  CONCLUSIONS
  The study confirms a beneficial impact of the first 25 years of the dust standard established by the 1969 act on the prevalence and severity of coal worker's pneumoconiosis in US coal miners. However, pneumoconiosis continues to occur among miners who have worked entirely within the contemporary standard, suggesting a need for further reductions in exposure to respirable coal mine dust.
authors: Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA.
authors: Val
authors: V
authors: Vallyathan
authors: Douglas P
authors: DP
authors: Landsittel
authors: Edward L
authors: EL
authors: Petsonk
authors: Jeffrey
authors: J
authors: Kahn
authors: John E
authors: JE
authors: Parker
authors: Karen Tofflemire
authors: KT
authors: Osiowy
authors: Francis H Y
authors: FH
authors: Green
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055008:Anthracosis / Q000453:epidemiology* / Q000266:history / Q000473:pathology / Q000517:prevention & control*; D001344:Autopsy; D003032:Coal Mining / Q000266:history / Q000331:legislation & jurisprudence / Q000592:standards*; D049673:History, 20th Century; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000453:epidemiology* / Q000266:history / Q000473:pathology / Q000517:prevention & control*; D016273:Occupational Exposure / Q000266:history / Q000331:legislation & jurisprudence / Q000517:prevention & control / Q000592:standards; D015995:Prevalence; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology; D055815:Young Adult