Pleural Cavity Article

Asbestos and Disease.

Of the various types of asbestos, four have been used commercially. These are, chrysotile or white asbestos, crocidolite or blue asbestos, amosite and anthrophyllite. Chrysotile is most used and in the USA accounts for 99% of current usage.

Asbestos was used widely in the past because of its fire resistant properties. It occurs naturally, and can be released into the atmosphere naturally. There is a minute trace of asbestos in the air and this level is slightly higher in towns and cities. Asbestos can also be in water following breakdown of natural deposits. It is insoluble in water.

Asbestos fibres are very fine. It is about 2000 times smaller than the width of a human hair. The fibres are sharp and measures less than 0.3 microns or one millionth of a millimetre in diameter and five microns in length. Not only are they not visible to the naked eye, they cannot be seen under a microscope.

Asbestos becomes a serious hazard to health when these fine particles are separated. If asbestos in homes and industries is well contained in items such as cement and tiles, and are not disturbed, the risk of developing asbestos related disease is minimal. Problems with exposure develop during drilling, sawing or careless demolition.

Since asbestos fibres are so fine, it remains in the air for a long time and can be carried a great distance from the site of initial release. It is therefore possible that you can inhale higher than normal quantities of asbestos without knowing it. Asbestos fibres enter the body mainly by inhalation but can be swallowed. The fibres remain in the lung and become embedded. It is not expelled by coughing or breathing out. Some of the fibres remain in the lungs. Others gravitate to the pleural lining. These fibres cause scarring and eventually cancers. How exactly this happens, is not clear but it is suggested that the body defence mechanism, such as white cells of blood, try to absorb the fibres and in the process, release damaging chemicals that injure surrounding tissue.

Asbestos exposure can result over time in asbestosis, pleural plaques, lung cancers and mesothelioma. Professor Julian Peto said, “Every single person in UK has some asbestos in their lungs. It is the level of exposure and the frequency that’s important. All the established cases of mesothelioma so far have been due to high and regular exposure. What we don’t know, is if the lower levels due to environmental exposure cause mesothelioma.” A recent article in the Daily Mail highlighted a case of mesothelioma in a Hospital consultant. He could not remember any significant asbestos exposure. It highlights the problem that we could be exposed to asbestos without our knowledge.

We know cigarette smoking causes lung cancer but a study on asbestos workers who smoked showed that they had eight times greater risk of developing lung cancers that other smokers. Asbestos workers who smoke are 92 times more likely to develop lung cancer than non-smokers with no history of asbestos exposure.

A study in 1992 of 2601 lung cancer cases showed that one in eight men had asbestos exposure and of these a third were still smoking.

So even though asbestos exposure seems closely linked to mesothelioma, remember that there is also a link with lung cancer. If you are worried that you were exposed to asbestos in the past, it is vitally important, if you are a smoker, that you stop smoking. This is perhaps the best preventative measure you can take.