title: Persistence of respiratory symptoms in ex-underground iron ore miners.
abstract: OBJECTIVE
  To assess the persistence of respiratory symptoms in ex-miners after cessation of mining exposure.
  
  
  METHODS
  Population-based cross-sectional study using a postal questionnaire comparing prevalence of symptoms between ex-miners who had stopped mining at least 1 year before the study and referents not occupationally exposed to irritants or dust. Age, smoking and a family history of asthma were considered as possible confounders in the analysis.
  
  
  RESULTS
  A total of 206 ex-miners and 4,560 referents participated. Ex-miners had on average been working as miners for 13 years and had stopped mining 16 years before the study. Chronic productive cough and physician-diagnosed chronic bronchitis were significantly more common among ex-miners (P < 0.05 and <0.01, respectively). Furthermore, there was a trend that other respiratory symptoms were more common in ex-miners.
  
  
  CONCLUSIONS
  Ex-miners had an increased risk of chronic productive cough and physician-diagnosed chronic bronchitis many years after they had stopped working as a miner.
authors.affiliation: Occupational Medicine, Department of Public Health and Clinical Medicine, Umeå University, SE-901 85 Umeå, Sweden. ulf.hedlund@envmed.umu.se
authors.forename: Ulf
authors.initials: U
authors.lastname: Hedlund
authors.forename: B
authors.initials: B
authors.lastname: Järvholm
authors.forename: B
authors.initials: B
authors.lastname: Lundbäck
mesh_terms: D029481:Bronchitis, Chronic / Q000503:physiopathology*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004391:Dust; D005541:Forced Expiratory Volume; D006801:Humans; D007501:Iron; D008168:Lung / Q000503:physiopathology*; D008173:Lung Diseases, Obstructive / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D008906:Mining; D015999:Multivariate Analysis; D009784:Occupational Diseases / Q000503:physiopathology*; D016273:Occupational Exposure; D015995:Prevalence; D012179:Retirement; D012907:Smoking / Q000009:adverse effects; D013548:Sweden
chemical_list: D004391:Dust; D007501:Iron