Risk Factors of Mesothelioma

The predominant cause of mesothelioma is exposure to asbestos - according to some estimations cancer of mesothelium is caused by asbestos exposure in about 80% of all patient. For that reason the greatest risk factor of mesothelioma is direct or indirect contact with asbestos and asbestos products although mesothelioma has been also reported in people without known exposure to asbestos. However, some experts are convinced that the percentage of people who suffer from mesothelioma because of exposure to asbestos would be a lot higher if their contact with asbestos would be better researched. Asbestos was not only used in construction and building industries but in variety of other industries and manufacture of products such as automobile brake pads and even textiles, and thus many people could be exposed to asbestos without even being aware of it.

The risk of mesothelioma, like other asbestos related diseases, is the greatest in people who worked with asbestos such as people who worked in asbestos mines and mills, workers who manufactured asbestos products, workers in the construction industry, shipbuilders, demolition workers as well as all who lived near asbestos mines, mills and factories. In greater risk of developing mesothelioma are also family members and others living with asbestos workers who could have brought asbestos fibers home on their clothes or hair. However, all who had been heavily exposed to asbestos do not develop mesothelioma or any other asbestos related disease, while asbestos fibers were fatal for many people who were exposed to asbestos only for a sort period. The amount of asbestos fibers that needs to be inhaled to cause mesothelioma is unknown but in theory already one asbestos fiber is potentially carcinogen. Either way, incidence of mesothelioma is higher in people who have been heavily exposed to asbestos.

There is no association between smoking and mesothelioma but experts assume that a combination of smoking and asbestos exposure greatly increases the risk of developing mesothelioma.

Who are at high risk for development of mesothelioma?

Asbestos is mined, milled and used in a variety of industrial and commercial products. Asbestos was used in insulations, textile industry, heat protectors, filters, and construction industry. Occupational exposure to asbestos may have occurred to asbestos miners, millers and producers of asbestos products, and workers who install plumbing, boilers and heating equipment in ships factories and homes. It is not necessary for the worker to handle the asbestos products directly to have a higher risk of developing mesothelioma, but working in the environment in proximity to asbestos may be sufficient. Carpenters, electricians, welders and many other workers who may have worked in the shipyard may have been exposed to asbestos and could be in the high-risk category for mesothelioma.

Mesothelioma exposure puts grave risk to the workers. One study has suggested that up to 10% asbestos workers may have died as the direct result of mesothelioma development. The time period between the initial exposure to a disease causing agent and development of disease known as lag period. Mesothelioma is a disease with a very long lag period. Average lag period associated with the development of mesothelioma is around 30 to 40 years and it could be as long as 65 years or more. Different subtypes of asbestos are associated with varying risk of development of mesothelioma. A subtype of asbestos, namely crocidolite is shown to be associated with higher risk of mesothelioma in miners, manufacturers and workers who install asbestos products. Another subgroup, amosite is associated with intermediate risk of development of mesothelioma. Chrysolite, which is currently the major form of asbestos in production, probably has the weakest association with the development of mesothelioma. Prior to restrictions imposed on asbestos use, a variety of workers were exposed to asbestos. The high-risk workers included asbestos minors, insulators, asbestos producers and asbestos manufacturers. Heating and construction workers also had very high risk of exposure to asbestos. People in this occupation with history of exposure to asbestos during early adulthood have a very high risk of development of mesothelioma. It is estimated that such workers have a lifetime risk of about 20 percent for the development of mesothelioma. The risk of mesothelioma development is not confined to workers who directly handle asbestos products as in the case of workers mentioned above. Other workers who work in close proximity to these occupational groups in construction sites, but had no direct contact with asbestos, have a high risk of development of mesothelioma. Workers who had no direct contact with asbestos have a relatively lower risk of development of mesothelioma compared to those who worked in direct contact. Exposure to asbestos may also increase the risk of other cancers. These cancers include lung cancer (about 4 to 5 fold increase) and pancreatic cancer.

People At Risk for Mesothelioma

Unfortunately, there are numerous people at risk for Mesothelioma based on the types of jobs they have had. For example, the following trades or occupations are considered as high risk: oil refinery workers, people working in factories that manufacture asbestos, mechanics, tile contractors, rail yard and power plant workers, shipyard workers, construction workers, brick layers, ship builders, welders, electricians, sand blasters, plumbers, and sheet metal workers.

Individuals At Risk For Developing Mesothelioma

The following represents some of the individuals who are at risk for developing mesothelioma or asbestosis.

• Brick layers, plumbers, sand blasters, sheet metal workers, millwrights, welders, painters, longshoremen, merchant marines, grinders, electricians, drywall contractors, miners, drillers, building inspectors and maintenance personnel.

• Any job that includes the manufacturing of asbestos, for example: insulation, fireproofing, plumbing supplies, roofing components, or other building materials and supplies such as cement, pipe coverings, refractory materials, gaskets, floor tiles and joint compounds.

• Individuals employed in the railroad, factory, shipyard, automobile, and construction and building industries during the last six decades.
  

• People working in factories that manufacture asbestos.

• Mechanics are at risk due to asbestos that is used in brake and clutch linings.

• Tile contractors are at risk due to the dust from cutting some types of tile.

There is strong evidence in the medical literature that the dangers of asbestos exposure were known long before millions of American workers were exposed.

• Oil refinery workers, rail yard and power plant workers can be at risk from various sources of asbestos.

• Shipyard and/or ship builders are at risk due to the asbestos in pipe insulation and other sources.

What type of jobs are at risk for developing asbestosis or mesothelioma? Any job that includes the manufacturing of asbestos, for example: insulation, fireproofing, plumbing supplies, roofing components, or other building materials and supplies such as cement, pipe coverings, refractory materials, gaskets, floor tiles and joint compounds.

• Steel mill workers can come into contact with asbestos from a variety sources due to the fact that steel mills frequently use asbestos as an insulator (especially when employees are required to work in high-temperature areas).

• Navy veterans and maritime workers.
  
• Construction workers can be at risk, especially those who do demolition of older buildings

Individuals employed in the railroad, factory, shipyard, automobile, and construction and building industries during the last six decades are at the risk of developing asbestosis or mesothelioma symptoms.

People At Risk for Mesothelioma: Conclusion

Regrettably, there are many people at risk for Mesothelioma due to the types of employment they have had.

For instance, the following trades or occupations are considered as high risk: rail yard and power plant workers, mechanics, oil refinery workers, shipyard workers, construction workers, sand blasters, brick layers, sheet metal workers, people working in factories that manufacture asbestos, ship builders, electricians, tile contractors, welders, and plumbers.

Mesothelioma Risk Factors

Risk factors are environmental, hereditary, or behavioral conditions that increase a person’s chances of getting a disease. Risk factors do not control whether someone gets a disease or not; they are simply the statistically-associated factors that seem to indicate that the development of a disease is more likely. For example, the primary risk factor for developing lung cancer is whether a person smokes tobacco or not. Other factors such as diet, hereditary predisposition to cancer, and so forth also affect the odds, and are also considered risk factors in assessing the chances that someone will develop the disease.

For malignant mesothelioma, the primary risk factor is absolutely clear: exposure to asbestos. Approximately 90 percent of malignant mesothelioma cases are in individuals who have had major occupational or environmental exposure to asbestos. At least eight million Americans have had sufficient exposure to asbestos, either in their jobs, through exposure to friable asbestos in commercial products or in homes or schools, or through secondary exposure to someone who worked in asbestos-using industries, to be considered at risk for malignant mesothelioma.

There are three primary factors in determining the risk posed to an individual by asbestos exposure: the time of the exposure, the duration of the exposure, and the level of the exposure. Malignant mesothelioma has a very long latency period – from 20 to 50 years in the majority of cases. Exposure to asbestos at young ages is therefore worse than exposure at an older age; asbestos exposure at age 70, for example, is unlikely to develop into malignant mesothelioma since the exposed person is likely to die of other causes long before the mesothelioma has a chance to form.

Exposure to high levels of asbestos is worse than exposure to modest levels; it is better to have gone to school in a building with some crumbling asbestos tiles than to have worked in an asbestos mine. Exposure over a long period of time is worse than exposure for brief periods. One grim fact of asbestos exposure and mesothelioma risk is that the passage of time without exposure does not reduce the risk; the body does not repair or recover from asbestos exposure the way it can from things like tobacco smoking.

Although asbestos exposure is the primary risk factor for mesothelioma, there are some other risk factors which can contribute to the disease.

Radiation, specifically exposure to thorium dioxide, has been linked to at least a few cases of mesothelioma.

Zeolite, a silicate mineral found mainly in Turkey, is similar to asbestos and is thought to have a similar ability to cause malignant mesothelioma.

Tobacco smoking, although not a direct risk factor, has been found to increase the incidence of mesothelioma in patients who also were exposed to asbestos.

The SV40 virus, a simian virus which some 10 to 30 million Americans were exposed to during the early days of the polio vaccine, is thought by some researchers to contribute to the development of malignant mesothelioma.