Unbound MEDLINE

Are airborne refractory ceramic fibers similar to asbestos in their carcinogenicity?

Abstract

BACKGROUND
Animal studies on refractory ceramic fiber (RCF) have led to the suggestion that RCF might resemble asbestos in carcinogenicity. Human data are available to test this hypothesis.
METHODS
We compared the occurrence of lung cancer and mesothelioma in 605 men engaged in the manufacture of RCF and followed since 1987 to cancer rates that would have been anticipated if airborne RCF were carcinogenic to the same degree as are crocidolite, amosite or chrysotile asbestos. We integrated the results of workplace exposure monitoring with mortality follow-up using formulas presented by Hodgson and Darnton (2000) to estimate hypothesized risks under different asbestos scenarios.
RESULTS
During 15,281 person-years of observation, there were 12 deaths from lung cancer. General population rates predicted 11.8 cases expected for an observed/expected (O/E) ratio of 1.0. Anticipated numbers of deaths from lung cancer under hypotheses of carcinogenicity similar to that of amphiboles and chrysotile were 62 and 17, allowing for rejection of amphibole-like effects (p < 10(-5)) but not chrysotile-like carcinogenicity (p = 0.15). There were no cases of mesothelioma, as compared to 4.9 anticipated under a crocidolite-like hypothesis (p = 0.007 to reject), 1.0 for amosite (p = 0.38) and 0.05 for chrysotile (p = 0.95).
CONCLUSION
There was no increase in lung cancer or mesothelioma in these workers exposed to RCF. If the cohort had the same exposure to crocidolite asbestos the number of lung cancer and mesothelioma cases would have been significantly greater than observed. The data do not yet permit a similar conclusion with respect to chrysotile asbestos.

Links

  • Publisher Full Text
  • Authors

    Walker AM, Maxim LD, Utell MJ

    Source

    Inhalation toxicology 24:7 2012 Jun pg 416-24

    MeSH

    Adult
    Aged
    Aged, 80 and over
    Air Pollutants, Occupational
    Asbestos
    Carcinogens
    Ceramics
    Humans
    Lung Neoplasms
    Male
    Mesothelioma
    Middle Aged
    Mineral Fibers
    Occupational Diseases
    Occupational Exposure

    Pub Type(s)

    Journal Article
    Research Support, Non-U.S. Gov't

    Language

    eng

    PubMed ID

    22642290