Asbestos Fibre Concentrations in the Lungs of Brake Workers: Another Look
Wednesday, June 25th, 2008.
Annals of Occupational Hygiene. 2008 Jun 23. [Epub ahead of print] [Link]
Finkelstein MM.
Family Medicine Centre, Mount Sinai Hospital, 60 Murray Street, 4th Floor, Toronto, Ontario, Canada M5T 3L9.
Abstract
Objective: To reanalyse data on the lung content of asbestos fibres among brake mechanics.
Methods: I re-analysed data published by Butnor, Roggli and colleagues on the lung content of chrysotile and tremolite asbestos fibres among brake mechanics and controls. Statistics of the distributions were estimated by maximum likelihood to accommodate observations below the detection limit. Mean concentrations were compared by the t-test, bootstrap resampling and interval-censored survival methods.
Results: The mean concentrations of fibres were higher among the brake workers than the controls. The concentration of tremolite fibres was higher than the concentration of chrysotile, a pattern similar to that observed among Quebec chrysotile miners and millers.
Conclusions: Re-analysis of published data does not support the interpretation that, in automotive brake repair workers with malignant mesothelioma, asbestos content is within the normal range. The alternative interpretation that brake mechanics have a greater than background burden of asbestos fibres, attributable to occupational exposure to dusts from friction products manufactured from Canadian chrysotile, appears more credible. This asbestos burden might be associated with an increased risk of asbestos-associated cancers.
Keywords: asbestos brakes • friction products • lung fibre content
Glossary
- detection
- finding disease. Early detection means that the disease is found at an early stage, before it has grown large or spread to other sites. Note many forms of cancer can reach an advanced stage without causing symptoms. Mammography can help to find breast cancer early, and the PSA blood test is useful in finding prostate cancer.
- mesothelioma
- a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.
