title: A 20-year follow-up study on the effects of long-term exposure to thorium dust.
abstract: OBJECTIVE
  To investigate the possible effects of long-term exposure to dust containing thorium and thoron progeny on dust-exposed miners.
  
  
  METHODS
  A negative, high voltage, exhaled thoron progeny measurement system was used to estimate the miners' thorium lung burden.
  
  
  RESULTS
  The highest thorium lung burden of 638 miners was 11.11 Bq. The incidence of stage 0(+) pneumoconiosis was higher among dust-exposed miners. Lung cancer mortality of the dust-exposed miners was significantly higher than that of controls (P < 0.005).
  
  
  CONCLUSIONS
  There is a difference in cancer rates between those who have long-term exposure to dust containing thorium (in which carcinogenic ThO(2) and SiO(2) exist) and thoron progeny and those who have not.
authors.affiliation: Laboratory of Industrial Hygiene, Ministry of Health, Beijing 100088, China. chenxing_an@hotmail.com
authors.forename: Xing'an
authors.initials: X
authors.lastname: Chen
authors.forename: Yonge
authors.initials: Y
authors.lastname: Cheng
authors.forename: Huijuan
authors.initials: H
authors.lastname: Xiao
authors.forename: Guodong
authors.initials: G
authors.lastname: Feng
authors.forename: Yunhui
authors.initials: Y
authors.lastname: Deng
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Feng
authors.forename: Lian
authors.initials: L
authors.lastname: Chen
authors.forename: Xuanmao
authors.initials: X
authors.lastname: Han
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Yang
authors.forename: Zhihuan
authors.initials: Z
authors.lastname: Dong
authors.forename: Rong
authors.initials: R
authors.lastname: Zhen
mesh_terms: D000396:Air Pollutants, Radioactive / Q000009:adverse effects; D001822:Body Burden; D002681:China / Q000453:epidemiology; D004391:Dust; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology*; D008906:Mining; D009784:Occupational Diseases / Q000453:epidemiology*; D016273:Occupational Exposure / Q000009:adverse effects; D013910:Thorium / Q000009:adverse effects*
chemical_list: D000396:Air Pollutants, Radioactive; D004391:Dust; D013910:Thorium