Silicosis exposure-response in a cohort of tin miners comparing alternate exposure metrics

Details

• Personal Author:
  Chen W ; Park RM ; Chen W ; Park RM
• Description:
  BACKGROUND: The detailed lung radiographic response to silica exposure has not been described. In estimating the exposure-response relationship in silicosis with statistical models, the absence of baseline (unattributable) risk can disable relative-rate estimation or produce widely varying estimates. This obstructs identification of optimum exposure metrics and invalidates comparisons and meta-analyses, which assume a common background rate. METHODS: A cohort of 3,000 Chinese tin miners with more than 1,000 cases of silicosis was analyzed for the period 1961-1994. Regular surveillance documented three stages of silicosis. To examine the exposure-response relationship, the intercept in relative-rate models was fixed to correspond to 1% of the observed silicosis rate. Exposure metrics for contributions in different time-windows were simultaneously evaluated, as were burden and cumulative burden metrics. RESULTS: Silica exposures that most contributed to silicosis onset occurred in the period 5-10 years prior (excess annual rate per 10 mg-year/m(3), ER = 0.158, 95% CI = 0.125-0.192, or 16% per year). During 10-20 year prior, the excess rate contribution was much smaller (ER = 0.048, 95% CI = 0.037-0.060) but larger again during 20-30 year prior to onset (ER = 0.112, 95% CI = 0.098-0.126). For advanced silicosis, all time periods contributed about equally to the rate of onset. CONCLUSIONS: Reliable estimates of parameters were observed, demonstrating exposure contributions over time. Burden metrics with different half-lives suggested some reversibility for silicosis onset with a half-life of 20 years. Advanced silicosis was best predicted with a cumulative burden metric which was consistent with prior observations that previously deposited silica continues to cause pulmonary damage. [Description provided by NIOSH]
• Subjects:
  Environmental Monitoring Lung Diseases Mining Occupational Exposure Occupational Health Radiography Respiratory Tract Diseases Risk Assessment Safety Silicon Dioxide Tin Compounds

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• Keywords:
  Analytical-processes Author Keywords: Burden Cumulative Exposure Dose-response Employee-exposure Exposure-assessment Exposure Response Lung-disease Lung-disorders Mine-workers Miners Mining-industry Occupational Disease Pulmonary-system-disorders Radiographic-analysis Respiratory-system-disorders Risk-analysis Silica-dusts Silicosis Statistical-analysis Statistical-quality-control Surveillance-programs Tin-compounds Vanishing Baseline

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• ISSN:
  0271-3586
• Document Type:
  Text
• Genre:
  Journal Article ; Journal Article
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH) ; National Institute for Occupational Safety and Health (NIOSH)
• Division:
  EID - Education and Information Division ; EID - Education and Information Division
• Topic:
  Workplace Safety & Health ; Workplace Safety & Health
• Location:
  North America ; North America
• Pages in Document:
  267-275
• Volume:
  56
• Issue:
  3
• NIOSHTIC Number:
  nn:20041561
• Citation:
  Am J Ind Med 2013 Mar; 56(3):267-275
• Contact Point Address:
  Robert M. Park, MS, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Education and Information Division, MSC-15,4676 Columbia Parkway, Cincinnati,OH45226
• Email:
  rhp9@cdc.gov
• CAS Registry Number:
  Quartz (SiO2) (CAS RN 14808-60-7) ; Silica (CAS RN 7631-86-9) ; Quartz (SiO2) (CAS RN 14808-60-7) ; Silica (CAS RN 7631-86-9)
• Federal Fiscal Year:
  2013
• NORA Priority Area:
  Construction ; Mining ; Construction ; Mining
• Peer Reviewed:
  True
• Source Full Name:
  American Journal of Industrial Medicine
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:214e5486233754511cd91a4694a67f5aed175b1dcfcdd5aeb264081536d09f99bc8f14059d8666f34d295bd18df9548eca4748efd4fbf8b5b51e58d9e7aedb3d
• Download URL:
  https://stacks.cdc.gov/view/cdc/194096/cdc_194096_DS1.pdf
• File Type:
  [PDF - 155.14 KB ]