Risk Factors
Asbestos exposure: The primary risk factor for mesothelioma
Asbestos is a mineral that's found naturally in the environment. Asbestos fibers are strong and resistant to heat, making them useful in a wide variety of applications, such as in insulation, cement, brakes, shingles, flooring and many other products. People who work around asbestos fibers are thought to have the greatest risk of mesothelioma.
When asbestos is broken up, such as during the mining process or when removing asbestos insulation, dust may be created. If the dust is inhaled or swallowed, the asbestos fibers may settle in the lungs or in the stomach, where they can cause irritation that may lead to mesothelioma, though how exactly this happens isn't understood.
Mesothelioma risk is believed to be increased in people who are exposed to high levels of asbestos, in people who are exposed to asbestos over a long period of time and in people exposed to asbestos at a young age. It can take 30 to 40 years or more for mesothelioma to develop as a result of asbestos exposure.
Some people with years of asbestos exposure never develop mesothelioma. And yet, others with very brief exposure develop the disease. This indicates that other factors may be involved in determining whether someone gets mesothelioma or doesn't. For instance, you could inherit a predisposition to cancer or some other condition could increase your risk.
Possible risk factors
Factors that may increase the risk of mesothelioma include:
- Personal history of asbestos exposure. If you've been directly exposed to asbestos fibers at work or at home, your risk of mesothelioma is greatly increased.
- Living with someone who works with asbestos. People who are exposed to asbestos may carry the fibers home on their skin and clothing. These stray fibers can put others in the home at risk of mesothelioma. People who work with asbestos should shower and change clothes before leaving work.
- Smoking. Risk of mesothelioma is increased greatly in smokers who are exposed to asbestos.
- SV40. Some research indicates a link between mesothelioma and simian virus 40 (SV40), a virus originally found in monkeys. Millions of people may have been exposed to SV40 when receiving polio vaccinations between 1955 and 1963, because the vaccine was developed using monkey cells. Once it was discovered that SV40 was linked to certain cancers, the virus was removed from the polio vaccine. Whether SV40 increases the risk of mesothelioma is a point of debate, and more research is needed.
- Radiation. Some research links mesothelioma to the radioactive substance thorium dioxide, which was used along with X-rays to diagnose various health conditions from the 1920s to the 1950s. Thorium dioxide was later found to cause cancer and is no longer used.
- Family history. A family history of mesothelioma may increase your risk of mesothelioma, but more research is needed to understand this theory.
There are different kinds of asbestos. The most common forms are:
- "White" asbestos or Chrysotile which is obtained from serpentine rocks. Chrysotile is the type most often used in industry. It is more flexible than other types of asbestos and can be spun and woven into fabric. This is the kind of asbestos used in theatre curtains and firefighters' suits.
- "Brown" asbestos or Amosite is a trade name for the amphiboles belonging to the Cummingtonite - Grunerite solid solution series, commonly from Africa.
- "Blue" asbestos or Riebeckite is also known under the name of Crocidolite. Blue asbestos is commonly thought of as the most dangerous type of asbestos.
In the United States, chrysotile has been the most commonly used type of asbestos. Chrysotile was often present in a wide variety of materials, including but not limited to:
- sheetrock taping
- mud and texture coats
- vinyl floor tiles, sheeting, adhesives and ceiling tiles
- plasters and stuccos
- roofing tars, felts, siding, and shingles
- "transite" panels, siding, countertops, and pipes
- acoustical ceilings
- fireproofing
- putty
- caulk
- gaskets
- brake pads and shoes
- clutch plates
- stage curtains
- fire blankets
- interior fire doors
- fireproof clothing for firefighters
- refractory cements and papers
Content provided by Mayo Foundation for Medical Education and Research (MFMER) and www.survivingmesothelioma.com
