Asbestos is the most common cause of mesothelioma. Over 9 out of 10 cases of mesothelioma (90%) are caused by exposure to asbestos fibres. Asbestos is a natural mineral found in many countries.
There are three main types of asbestos:
- blue (crocidolite)
- brown (amosite)
- white (chrysotile).
They were used in UK industries until the ban on imports of blue and brown asbestos in the 1980s, and on all types in 1999. Exposure to blue and brown asbestos is commonly linked with mesothelioma. However, exposure to all types of asbestos is harmful.
Mesothelioma does not usually develop until many years after exposure to asbestos. It can take from 15 to 60 years. But the average is about 30 to 50 years after exposure for pleural mesothelioma. It may be less time for peritoneal.
When asbestos is damaged or disturbed (often by hitting, rubbing or handling), it releases tiny fibres. These fibres can be breathed into the lungs. Asbestos fibres are very fine and can get into the smallest airways of the lungs. Once the fibres are in the lungs, the body’s defence mechanisms try to break them down and remove them. This leads to inflammation in the lung tissue. The asbestos fibres can also travel through the lung tissue and settle in the outer lining of the lung (the pleura). Over many years, these fibres can cause pleural mesothelioma or other lung conditions to develop.
Asbestos fibres can also be swallowed, and some of the fibres can get stuck in the digestive system. They can then move into the outer lining of the abdomen (the peritoneum). Here, they cause swelling and thickening of the lining. This can lead to peritoneal mesothelioma.
Exposure to asbestos
People most likely to have been exposed to asbestos at work include:
- joiners and construction workers
Mesothelioma is five times more common in men than in women. This is because when asbestos was used in these industries, it was mostly men who did these types of jobs.
People who have not worked directly with asbestos can also sometimes develop mesothelioma. For example:
- family members of people who have worked with asbestos and unknowingly brought the dust home on their clothes
- people who lived near asbestos factories
- people who worked in buildings containing asbestos materials that were damaged or disturbed.
If you develop an asbestos-related illness, you may be entitled to certain benefits and compensation. Occasionally, mesothelioma develops in people who did not know that they have been exposed to asbestos.
The other causes of mesothelioma are not fully understood. In rare cases, mesothelioma has been linked to:
- exposure to radiotherapy
- a mineral called erionite, which has been found in Turkey and North America.
Mesothelioma is not infectious and cannot be passed on to other people. Doctors do not know why some people who are exposed to asbestos get mesothelioma and others do not. Early research shows that people with changes in certain genes may have a higher risk of developing mesothelioma than others when they are exposed to asbestos.