| The major risk factor for
mesothelioma is exposure to asbestos. Only about 20% of the cases reported
occur due to other reasons. These reasons are not vivid as yet. Asbestos is
a the name of a category of minerals, and finds extensive use in several
industrial products, including cement, brake linings, flooring products,
roof shingles, textiles, and insulation. During the process of
manufacturing, several small fibres float in air, which are inhaled and
swallowed. Over a period of time, these asbestos fibres reach a threshold
concentration in lungs and pleura, and lead to several complicated
disorders. Besides mesothelioma, exposure to asbestos multiplies the risk of
other health ailments like lung cancer, asbestosis, and other cancers such
as the ones of lungs and kidney.
Asbestos Mesothelioma Facts
In the groups of workers with cumulative
exposures to asbestos ranging from about 5 to 1200 fibre-year/ mL, diseases
like lung cancer, mesothelioma, asbestosis etc. are found extensively. Such
exposures result from 40 years of occupational exposure to air
concentrations of 0.125 to 30 fiber/ Ml.
Tremolite asbestos exposure has been
associated with an increased incidence of disease in vermiculite miners and
millers from Libby, Montana.
Long and thin fibres reach the lower
airways and alveoli of lungs, where they are retained for longer. These
fibres are more toxic than short and wide fibres or particles. Wide
particles deposit in the upper respiratory tract and do not reach the lung
and pleura, which are the sites of asbestos-induced toxicity. Short, thin
fibres play in role in asbestos pathogenesis.
Fibers of amphibole asbestos, for instance,
tremolite asbestos, actinolite asbestos, and crocidolite asbestos are
retained longer in the lower respiratory tract than chrysotile fibres of
similar dimensions.
70-80% of the reported cases of
mesothelioma occur due to chronic exposure to asbestos fibres.
Malignant pleural mesothelioma is an
extremely painful cancer.
Smoking does not appear to increase the
risk of mesothelioma, however, the combination of smoking and asbestos
exposure steeply raises the slope of a person’s risk of developing cancer of
the air passageways in the lung.
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