Blue Collar Workers and the Mesothelioma Menace

Manual laborers suffer from mesothelioma disease in an inordinate amount.  This has been the subject of much research.  One important study is called, "Analysis of the cores of asbestos bodies from members of the general population: patients with probable low-degree exposure to asbestos" by Churg A, Warnock ML - Am Rev Respir Dis. 1979 Oct;120(4):781-6.  Here is an excerpt: "Abstract - Asbestos bodies were isolated from the lungs of 21 patients who had 300 to 9,000 of such bodies/g of lung tissue, a concentration frequently found in manual laborers in the general population who are not primary asbestos workers. All of the 123 bodies examined by electron diffraction produced diffraction patterns consistent with amphibole varieties of asbestos. Electron microprobe analysis (energy dispersive x-ray spectroscopy) of 46 bodies revealed that 38 of the cores were composed of the commercial amphiboles, amosite and crocidolite, whereas only 8 were composed of the noncommercial amphiboles, anthophyllite and tremolite. Review of the occupations of these patients revealed that all but one had blue-collar jobs. For many of these persons, putative sources of asbestos exposure such as construction work could be defined, but for some, the source could not be determined. One woman was apparently exposed to asbestos in the practice of her hobby of ceramics, in which she used anthophyllite-contaminated clay. We concluded that commercial amosite/crocidolite asbestos forms the cores of most asbestos bodies in manual laborers in the general population and that the source is usually occupational.

Fibre type and concentration in the lungs of workers in an asbestos cement factory by B Gylseth, G Mowé, A Wannag - Br J Ind Med 1983;40:375-379.  Here is an excerpt: "Abstract - The predominant asbestos fibre type used in the production of asbestos cement is chrysotile. The use of asbestos in relation to fibre type in a Norwegian asbestos cement plant during 1942-80 was 91.7% chrysotile, 3.1% amosite, 4.1% crocidolite, and 1.1% anthophyllite respectively. Electron microscopy and x ray microanalysis of lung tissue samples of asbestos cement workers who had died of malignant pleural mesothelioma or bronchogenic carcinoma showed a completely inverse ratio with regard to fibre type. The percentage of chrysotile asbestos in lung tissue varied between 0% and 9% whereas the corresponding numbers for the amphiboles were 76% and 99%. These differences are discussed with respect to the behaviour of different fibre types in the human body and to the occurrence of malignant mesothelioma in this asbestos cement factory."

Asbestos fiber length as related to potential pathogenicity: A critical review by Ronald F. Dodson, PhD, FCCP, FAHA, Mark A.L. Atkinson, MA, DPhil, Jeffrey L. Levin, MD, MSPH - The University of Texas Health Center at Tyler, Texas - American Journal of Industrial Medicine - Volume 44 Issue 3, Pages 291 – 297.  Here is an excerpt: "Abstract - Background - Asbestos inhalation is recognized as an exposure that increases the risk for the development of lung disease. It is unique among dusts in that it is both a carcinogen and capable of inducing extrapulmonary responses such as pleural thickening and fibrosis as well as malignancy. One feature of asbestos suggested as crucial in its pathological activity is its fibrous morphology. Long fibers that have been inhaled are cleared less readily and are thus more persistent in the body. Furthermore certain experimental models link fiber length to levels of risks for development of certain diseases. The present review will survey the data on this subject.

Methods - The review considers experimental models that have been used to assess the response to various lengths of fibers in animal models in addition to data obtained from studies of human materials. The review also emphasizes the importance in defining the method by which a sample is categorized. Results - Data are offered which support the potential for longer fibers as well as shorter fibers to contribute to pathological responses. Conclusions - The data presented argue that asbestos fibers of all lengths induce pathological responses and that caution should be exerted when attempting to exclude any population of inhaled fibers, based on their length, from being contributors to the potential for development of asbestos-related diseases. If you found any of these excerpts interesting, please read the studies in their entirety.