Crystalline Silica Exposure and Lung Cancer Mortality in Diatomaceous Earth Industry Workers: A Quantitative Risk Assessment

Details

• Personal Author:
  Checkoway, Harvey ; Gilbert S ; Park R ; Rice, Faye L. ; Smith R ; Stayner L
• Description:
  OBJECTIVE: To use various exposure-response models to estimate the risk of mortality from lung cancer due to occupational exposure to respirable crystalline silica dust. METHODS: Data from a cohort mortality study of 2342 white male California diatomaceous earth mining and processing workers exposed to crystalline silica dust (mainly cristobalite) were reanalyzed with Poisson regression and Cox's proportional hazards models. Internal and external adjustments were used to control for potential confounding from the effects of time since first observation, calendar time, age, and Hispanic ethnicity. Cubic smoothing spline models were used to assess the fit of the models. Exposures were lagged by 10 years. Evaluations of the fit of the models were performed by comparing their deviances. Lifetime risks of lung cancer were estimated up to age 85 with an actuarial approach that accounted for competing causes of death. RESULTS: Exposure to respirable crystalline silica dust was a significant predictor (p<0.05) in nearly all of the models evaluated and the linear relative rate model with a 10 year exposure lag seemed to give the best fit in the Poisson regression analysis. For those who died of lung cancer the linear relative rate model predicted rate ratios for mortality from lung cancer of about 1.6 for the mean cumulative exposure to respirable silica compared with no exposure. The excess lifetime risk (to age 85) of mortality from lung cancer for white men exposed for 45 years and with a 10 year lag period at the current Occupational Safety and Health Administration (OSHA) standard of about 0.05 mg/m3 for respirable cristobalite dust is 19/1000 (95% confidence interval (95% CI) 5/1000 to 46/1000). CONCLUSIONS: There was a significant risk of mortality from lung cancer that increased with cumulative exposure to respirable crystalline silica dust. The predicted number of deaths from lung cancer suggests that current occupational health standards may not be adequately protecting workers from the risk of lung cancer. [Description provided by NIOSH]
• Subjects:
  Dust Lung Lung Diseases Neoplasms Occupational Health Respiratory System Respiratory Tract Diseases Risk Assessment Safety Silicon Dioxide
• Keywords:
  Author Keywords: Crystalline Silica Cristobalite Dust-exposure Dusts Humans Lung-cancer Lung-disorders Lung Cancer Pulmonary-system-disorders Respirable-dust Respiratory-system-disorders Risk-analysis Silica-dusts Statistical-analysis

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• ISSN:
  1351-0711
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  EID - Education and Information Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  38-45
• Volume:
  58
• Issue:
  1
• NIOSHTIC Number:
  nn:20021850
• Citation:
  Occup Environ Med 2001 Jan; 58(1):38-45
• Email:
  frice@cdc.gov
• CAS Registry Number:
  Cristobalite (CAS RN 14464-46-1) ; Diatomite (CAS RN 61790-53-2) ; Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  2001
• Peer Reviewed:
  True
• Source Full Name:
  Occupational and Environmental Medicine
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:45eafd3b93e7305e970224772ed0c67614dab3079a59eaa1c8adb9f0050cdeaa0cce4bc46f1cdecbd0844c721520d745daf9491ff91e331aa44a917601bb3afa
• Download URL:
  https://stacks.cdc.gov/view/cdc/198946/cdc_198946_DS1.pdf
• File Type:
  [PDF - 262.41 KB ]