Analysis of occupational asbestos exposure and lung cancer mortality using the g formula

Am J Epidemiol. 2013 May 1;177(9):989-96. doi: 10.1093/aje/kws343. Epub 2013 Apr 4.

Abstract

We employed the parametric G formula to analyze lung cancer mortality in a cohort of textile manufacturing workers who were occupationally exposed to asbestos in South Carolina. A total of 3,002 adults with a median age of 24 years at enrollment (58% male, 81% Caucasian) were followed for 117,471 person-years between 1940 and 2001, and 195 lung cancer deaths were observed. Chrysotile asbestos exposure was measured in fiber-years per milliliter of air, and annual occupational exposures were estimated on the basis of detailed work histories. Sixteen percent of person-years involved exposure to asbestos, with a median exposure of 3.30 fiber-years/mL among those exposed. Lung cancer mortality by age 90 years under the observed asbestos exposure was 9.44%. In comparison with observed asbestos exposure, if the facility had operated under the current Occupational Safety and Health Administration asbestos exposure standard of <0.1 fibers/mL, we estimate that the cohort would have experienced 24% less lung cancer mortality by age 90 years (mortality ratio = 0.76, 95% confidence interval: 0.62, 0.94). A further reduction in asbestos exposure to a standard of <0.05 fibers/mL was estimated to have resulted in a minimal additional reduction in lung cancer mortality by age 90 years (mortality ratio = 0.75, 95% confidence interval: 0.61, 0.92).

Keywords: asbestos; bias (epidemiology); epidemiologic methods; healthy worker effect; occupations.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Asbestos, Serpentine / adverse effects*
  • Asbestos, Serpentine / analysis
  • Female
  • Government Regulation
  • Humans
  • Lung Neoplasms / etiology
  • Lung Neoplasms / mortality*
  • Lung Neoplasms / prevention & control
  • Male
  • Middle Aged
  • Mineral Fibers / adverse effects
  • Occupational Exposure / adverse effects*
  • Occupational Exposure / analysis
  • Occupational Exposure / legislation & jurisprudence
  • Occupational Exposure / prevention & control
  • South Carolina / epidemiology
  • Textile Industry / legislation & jurisprudence
  • Textile Industry / statistics & numerical data
  • Time Factors
  • United States
  • United States Occupational Safety and Health Administration / legislation & jurisprudence*
  • United States Occupational Safety and Health Administration / statistics & numerical data
  • Young Adult

Substances

  • Asbestos, Serpentine
  • Mineral Fibers