Mesothelioma Causes

The principal causative agent in a majority of mesotheliomas patients in the United States is asbestos exposure. Due to this hazardous effect of asbestos exposure, the U.S. Department of Health and Human Services, the EPA and the International Agency for Research on Cancer have classified asbestos as a substance which causes cancer in humans (a known human carcinogen).

Asbestos is a group of naturally occurring fibrous mineral found in several products used in our normal day to day life E.g. - cement, brake linings, roof shingles, flooring products, textiles, and insulation. It has been mined and used in various products since the late 1800s. During World War II the use of asbestos increased significantly. Although millions of Americans were exposed to asbestos from the late 1940s the adverse effects of exposure were largely unknown to the general public. Due to the hazardous effects of exposure to asbestos, all new uses of asbestos were banned by the U.S. Environmental Protection Agency (EPA) in 1989.

There are 2 main types of asbestos

Any form of asbestos is harmful to humans but according some research studies amphibole fibers stay in the lungs longer than chrysotile, and this tendency may account for their increased toxicity.

Routes of asbestos exposure

Air:
Asbestos fibers are strong and resistant heat, fire, chemicals and usually do not dissolve or breakdown in any way. When airborne fibers are inhaled by a person they travel through the airways and reach the lung coverings (pleura). Most of these fibers are expelled from the lungs but some fibers may remain in the lung tissue for a long period of time causing changes in the mesothelial cells which will result in uncontrolled growth of the cells and development of mesothelioma.

All of us are exposed to low levels of airborne asbestos fibers which pose little, if any risk to our health. For example, outdoor air in rural areas contains about 10 fibers per cubic meter (A cubic meter is about the amount of air that you breathe in 1 hour.) which is equivalent 0.00001 fibers per milliliter. But in the cities these values may be 10 fold higher than in rural areas. Significant health effects are caused when much higher concentration levels are present in the air.

Drinking water:
Asbestos fibers can also be found in water and when consumed, reaches the abdominal cavity and may cause peritoneal mesothelioma. Asbestos fibers may enter the drinking water from asbestos containing pipes which carry them.

Mesothelioma is a disease which is frequently seen in people who work with asbestos products or in people who are employed in factories that manufacture asbestos-containing products. The mesothelioma risk in these groups of people is several times higher than that of the general population.

The effect of asbestos exposure depends on various factors:

People may be exposed to asbestos fibers in:

 Work place:

In about 70-80% of mesothelioma patients a history of work related asbestos exposure can be found.  Examples of occupations with a risk of asbestos exposure are listed below.

Although the risk of acquiring mesothelioma is high in the occupational population mentioned above, a minority of mesetheliomas may be acquired by inhaling asbestos found in communities and at home.

 Communities:

 Homes

The mere presence of asbestos in a building does not pose a risk of fiber inhalation since Intact and undisturbed asbestos materials do not release asbestos fibers into air.

Other possible risk factors which play a role in developing mesothelioma are mentioned below:
Smoking – Smokers who are exposed to asbestos are at a higher risk of developing mesothelioma at some point of their life.
Simian virus 40 (SV40) - Some researches have establish an association between mesothelioma and simian virus 40 (SV40), but more research is needed to prove that the virus actually increases the risk of mesothelioma.
Radiation - Mesothelioma may be caused by radioactive substances which were used in X-rays during the period from the 1920s to the 1950s.

DISCLAIMER: All information provided on this website is for informational purpose only and cannot be understood as a medical opinion or advice of any sought or kind. Please consult your doctor for medical opinion.