What are the risk factors for mesothelioma?
Working with asbestos is the major risk factor for mesothelioma. A history of asbestos exposure at work is reported in about 70 percent to 80 percent of all cases. However, mesothelioma has been reported in some individuals without any known exposure to asbestos.
Asbestos is the name of a group of minerals that occur naturally as masses of strong, flexible fibers that can be separated into thin threads and woven. Asbestos has been widely used in many industrial products, including cement, brake linings, roof shingles, flooring products, textiles, and insulation. If tiny asbestos particles float in the air, especially during the manufacturing process, they may be inhaled or swallowed, and can cause serious health problems. In addition to mesothelioma, exposure to asbestos increases the risk of lung cancer, asbestosis (a noncancerous, chronic lung ailment), and other cancers, such as those of the larynx and kidney.
Smoking does not appear to increase the risk of mesothelioma. However, the combination of smoking and asbestos exposure significantly increases a person’s risk of developing cancer of the air passageways in the lung.
Who is at increased risk for developing mesothelioma?
Asbestos has been mined and used commercially since the late 1800s. Its use greatly increased during World War II. Since the early 1940s, millions of American workers have been exposed to asbestos dust. Initially, the risks associated with asbestos exposure were not known. However, an increased risk of developing mesothelioma was later found among shipyard workers, people who work in asbestos mines and mills, producers of asbestos products, workers in the heating and construction industries, and other tradespeople. Today, the U.S. Occupational Safety and Health Administration (OSHA) sets limits for acceptable levels of asbestos exposure in the workplace. People who work with asbestos wear personal protective equipment to lower their risk of exposure.
The risk of asbestos-related disease increases with heavier exposure to asbestos and longer exposure time. However, some individuals with only brief exposures have developed mesothelioma. On the other hand, not all workers who are heavily exposed develop asbestos-related diseases.
There is some evidence that family members and others living with asbestos workers have an increased risk of developing mesothelioma, and possibly other asbestos-related diseases. This risk may be the result of exposure to asbestos dust brought home on the clothing and hair of asbestos workers. To reduce the chance of exposing family members to asbestos fibers, asbestos workers are usually required to shower and change their clothing before leaving the workplace.
Asbestos exposure plays a role in 70 percent to 80 percent of mesothelioma cases, though the actual percentage could be higher. Asbestos is a mineral that is found naturally in the environment. Asbestos fibers are strong and resistant to heat, making them useful in a wide variety of applications. Asbestos fibers have been used to make 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 — for instance, in the mining process or in removing asbestos insulation from a building — 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. Although asbestos is still used in a limited number of industries, the federal government limits the amount of asbestos fibers workers may be exposed to and sets rules to protect workers.
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.
People who live with workers exposed to asbestos may also have an increased risk of mesothelioma. Asbestos dust is thought to have been carried home on workers' clothes. Today workers are required to shower and change clothes after working with asbestos to protect their families.
Some people with years of asbestos exposure never develop mesothelioma. Researchers estimate only about 5 percent of the people with the highest exposure to asbestos will 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. Risk of mesothelioma is increased greatly in smokers who are exposed to asbestos.
Other possible risk factors Researchers have identified other factors that may increase the risk of mesothelioma, including:
