Asbestos fiber concentrations in the lungs of brake repair workers: commercial amphiboles levels are predictive of chrysotile levels.

Journal Article (Journal Article)

OBJECTIVES: To investigate the impact of extreme data points in Finkelstein's 2009 findings of no association between lung levels of commercial and non-commercial amphiboles (principally tremolite as a marker for chrysotile asbestos) in brake repair workers with mesothelioma. METHODS: We first identified potential outliers, high leverage points, and influential points among lung levels of commercial amphiboles and tremolite among 15 persons whose only known exposure to asbestos was through brake repair work. We used sensitivity analysis and quantile regression to account for extreme data points and model commercial amphibole levels as a predictor of tremolite levels. We also used quantile regression to evaluate whether case-reported duration of employment as a brake repair worker predicted lung levels of commercial amphiboles or tremolite. RESULTS: We found lung levels of commercial amphiboles are a statistically significant predictor of tremolite levels via sensitivity analysis (r = 0.82, slope estimate P-value = 0.001, R² = 0.68) and quantile regression (slope estimate P-value <0.0001). Our data provide no evidence that duration of employment as a brake repair worker was a predictor of lung levels of tremolite or commercial amphiboles. CONCLUSIONS: Our findings suggest that elevated lung levels of tremolite in the lungs of brake repair workers with elevated levels of amphiboles arose from concurrent exposures to commercial amphibole and chrysotile asbestos in occupational settings other than brake repair work. These findings are supported by five new cases. The weight of the scientific evidence does not support a role for occupational exposure to brake dust and other friction products in the development of mesothelioma.

Full Text

Duke Authors

Cited Authors

  • Marsh, GM; Youk, AO; Roggli, VL

Published Date

  • October 2011

Published In

Volume / Issue

  • 23 / 12

Start / End Page

  • 681 - 688

PubMed ID

  • 21671853

Electronic International Standard Serial Number (EISSN)

  • 1091-7691

Digital Object Identifier (DOI)

  • 10.3109/08958378.2011.580472


  • eng

Conference Location

  • England