Occupational Silica Exposure and Mortality from Lung Cancer and Nonmalignant Respiratory Disease: G-Estimation of Structural Nested Accelerated Failure Time Models

Details

• Personal Author:
  Brown DM ; Checkoway, Harvey ; Costello S ; Eisen EA ; Neophytou AM ; Picciotto S
• Description:
  Background: Occupational exposure to crystalline silica is known to increase risks of both lung cancer and noninfectious nonmalignant respiratory diseases (NMRD). However, associations between silica exposure and survival times have not been described. Methods: In a longitudinal cohort of diatomaceous earth workers exposed to crystalline silica (primarily cristobalite) and followed from 1942 to 2011, we applied g-estimation of structural nested accelerated failure time models to adjust for time-varying confounding that could result in healthy worker survivor bias. A continuous measure of exposure was used in analyses estimating the hypothetical effect of banning exposure to silica on survival time. Since a ban is infeasible, sensitivity analyses examined the hypothetical effects of enforcing various Occupational Exposure Limits. Results: The estimated median number of years of life lost per worker (for all natural causes) due to silica exposure was 0.48 (95% confidence interval = 0.02, 1.01). For NMRD deaths, the corresponding estimate was 3.22 (0.82, 7.75) and for lung cancer deaths, 2.21 (0.97, 3.56). Cause-specific estimates were sensitive to the use of weights to adjust for competing events. Lung cancer mortality, which tended to occur at younger ages, was an important competing event for NMRD mortality. Sensitivity analyses supported the main results, but with larger estimates, and suggested that a strict limit would be nearly as effective as a complete ban on silica exposure. Conclusions: Workplace exposure to crystalline silica in this industry appears to shorten survival times significantly, particularly for those who die of lung cancer or NMRD. More stringent exposure limits are probably warranted. [Description provided by NIOSH]
• Subjects:
  Cohort Studies Dust Lung Lung Diseases Mortality Neoplasms Occupational Exposure Occupational Health Respiratory System Respiratory Tract Diseases Safety Silicon Dioxide

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• Keywords:
  Author Keywords: Diatomaceous Earth Cohort Studies Crystalline Silica Diatomaceous Earth Exposure Assessment G-estimation Healthy Worker Survivor Effect Lung Cancer Mortality Data Occupational Exposure Occupational Exposure Limits OELs Respirable Dust Respiratory Diseases Silica

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• ISSN:
  2474-7882
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  California ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  2
• Issue:
  3
• NIOSHTIC Number:
  nn:20056988
• Citation:
  Environ Epidemiol 2018 Sep; 2(3):e209
• Contact Point Address:
  Sally Picciotto, Environmental Health Sciences, UC Berkeley School of Public Health, 2121 Berkeley Way, No 5302, Berkeley, CA 94720
• Email:
  sallypicciotto@berkeley.edu
• CAS Registry Number:
  Diatomite (CAS RN 61790-53-2) ; Quartz (SiO2) (CAS RN 14808-60-7)
• Federal Fiscal Year:
  2018
• NORA Priority Area:
  Mining
• Performing Organization:
  University of California, Berkeley
• Peer Reviewed:
  True
• Start Date:
  20150901
• Source Full Name:
  Environmental Epidemiology
• End Date:
  20180831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:4defb00355829c19633f366cce2cb9e71c29d3fd13f4144581c40bc0ae22613ce819a479e8fcd04f21802627be0cd6421d5050762ad1184745b00e63a7a883ff
• Download URL:
  https://stacks.cdc.gov/view/cdc/214474/cdc_214474_DS1.pdf
• File Type:
  [PDF - 446.47 KB ]