title: Lung cancer risk and radon exposure in a cohort of iron ore miners in Malmberget, Sweden.
abstract: OBJECTIVE
  Lung cancer caused by radon in miners is a well-known risk. However, the risk estimates vary between studies and between mines. We have studied the dose response-relationship in a Swedish iron ore mine where two other studies have previously reached different risk estimates. As this mine has relatively low radon levels, the results are highly relevant for risk estimation in non-uranium underground mines.
  
  
  METHODS
  A new cohort of 5486 male workers employed from 1923 to 1996 was established. Cumulative radon exposures were assessed based on a large number of measurements, including reconstructions of historical conditions. 122 lung cancer cases occurred during the follow-up period of 1958-2000.
  
  
  RESULTS
  The average cumulative exposure in underground workers was 32 kBq year/m(3) (65 working level months (WLM)), experienced over 14.6 years. The excess RR (ERR) per kBq year/m(3) was 0.046 (95% CI 0.015 to 0.077; 0.022 ERR/WLM). Confounding by quartz may affect these results but appears to account only for 10-20% of the risk. The results for squamous cell and small cell lung cancer were 0.049 and 0.072, respectively. However, no increased risk was observed for adenocarcinoma (0.000 ERR per kBq year/m(3), 95% CI -0.017 to 0.017).
  
  
  CONCLUSIONS
  Our overall risk estimate is about half of that found in the first Malmberget study but twice that found in the same cohort in the previously published pooled analysis. Radon did not increase the risk for adenocarcinoma in the lung.
authors.affiliation: Oncology, Department of Radiation Sciences, Umeå University, Umeå, Sweden. hakan.jonsson@oc.umu.se
authors.forename: Håkan
authors.initials: H
authors.lastname: Jonsson
authors.forename: Ingvar A
authors.initials: IA
authors.lastname: Bergdahl
authors.forename: Gustav
authors.initials: G
authors.lastname: Akerblom
authors.forename: Kåre
authors.initials: K
authors.lastname: Eriksson
authors.forename: Kurt
authors.initials: K
authors.lastname: Andersson
authors.forename: Leif
authors.initials: L
authors.lastname: Kågström
authors.forename: Bengt
authors.initials: B
authors.lastname: Järvholm
authors.forename: Lena
authors.initials: L
authors.lastname: Damber
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007501:Iron / Q000633:toxicity*; D008175:Lung Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D008906:Mining; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology*; D009784:Occupational Diseases / Q000139:chemically induced / Q000453:epidemiology*; D016273:Occupational Exposure / Q000009:adverse effects*; D011886:Radon / Q000633:toxicity*; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology
chemical_list: D007501:Iron; D011886:Radon