Saturday, November 24, 2007

What Causes of Mesothelioma?

A. Asbestos

Mesothelioma is most predominantly caused by asbestos exposure. Working with asbestos is the major risk factor for mesothelioma.

Asbestos is an insulating material comprised of magnesium-silicate mineral fibers. 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.

Mesothelioma is most predominantly caused by asbestos exposure. Working with asbestos is the major risk factor for mesothelioma.

Inhaled asbestos fibers cause a physical irritation resulting in cancer rather than the cancer being caused by a reaction that is more chemical in nature. As fibers are inhaled through the mouth and nose they are cleared from the body by adhering to mucus in the nose, throat and airways and then get expelled by coughing or swallowing. The Amphibole fibers (long and thin) do not clear as easily and it is therefore thought that they can embed into the lining of the lungs and chest and result in mesothelioma.

Workers who sustain high levels of asbestos exposure are more likely to die from asbestosis, lung cancer or mesothelioma than any other disease.

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. Asbestos is a very dangerous substance and can cause a lot of damage to your health. It is made up of very small fibers, which can find their way to pleura (outside lining of the lung) and damage the cells pleura is made of. These fibers can also be carried on clothing, which makes them dangerous not only to the person exposed to asbestos, but to their family members as well.

Asbestos exposure is known to be responsible for a variety of health issues, including:

  1. Malignant mesothelioma
  2. Asbestos lung cancer
  3. Asbestosis
  4. Diffuse pleural thickening
  5. Fibrosis

Broad Classification of Asbestos

Article Source: http://EzineArticles.com/

There are two broad categories into which all types of asbestos can be classified. They are as follows:

1. Serpentine group. This type of asbestos has a layered form and the fibers are curly. This is why it is called as 'serpentine'. This group has just one member, called chrysolite. Basically, This is the most common type of asbestos.

2. Amphibole group .This is considered to be the most hazardous type of asbestos. It has straight fibers. Unlike the serpentine group, it has a chain like structure. Five kinds of asbestos are found in the amphibole group.

Types of Asbestos:

1. Chrysotile asbestos. Also called white asbestos, chrysolite is the most common type of asbestos. It belongs to the serpentine group. The construction industry makes vast use of this type of asbestos. Since this type of asbestos is widely used, the majority of the asbestos-related health problems globally are caused due to chrysolite. It is used in the following materials: fire proofing materials, insulation, woven to form asbestos clothes,
cement pipes, cement Sheets, automobile brake shoes, clutches, disk pads, textiles, plastics, paper,rubber and even in nuclear industry.

2. Tremolite asbestos. Tremolite asbestos is not often used industrially, though it was sometimes found in certain commercial products such as talcum powder.

3. Actinolite asbestos. Like tremolite, actinolite asbestos is not often used industrially. Airborne actinolite asbestos fibers are easily inhaled and severely damaging to the lungs.

4. Amosite asbestos. Also called brown asbestos. This belongs to the amphibole category of asbestos. It has very stiff and Strong fibers. These fibers get easily air borne and are Very dangerous when inhaled through the nose or mouth. It is known as brown asbestos. It is mostly used for insulating purposes. Most of the countries have banned this amosite several decades ago itself. After chrysolite, this was the most popularly used type of asbestos. Amosite asbestos is used for a variety of commercial purposes such as pipe and cement sheet insulation.

5. Crocidolite asbestos. Also called blue asbestos, crocidolite asbestos viewed as the most dangerous of the six. This is a very rare type of asbestos belonging to the amphibole category. It is mostly used to reinforce plastics as it is highly strong. It is slightly blue in color. It is also used in thermal insulation.

6. Anthophyllite asbestos. Like tremolite and actinolite, anthophylite asbestos is not often used industrially, though it can occasionally be found in certain types of vermiculite (natural minerals that expand with the application of heat).

Asbestos Exposure and Your Work
resource : ATSDR

Many people have come into contact with asbestos fibers through their jobs (occupational exposure). Some of the work environments or occupations in which workers are now or were exposed in the past include:

Work Environments.

- Asbestos product manufacturing (insulation, roofing, building, materials)
- Automotive repair (brakes & clutches)
- Construction sites
- Maritime operations
- Mining operations
- Offshore rust removals
- Oil refineries
- Power plants
- Railroads
- Sand or abrasive manufacturers
- Shipyards / ships / shipbuilders
- Steel mills

Occupations:

- Asbestos removal workers
- Workers at exfoliation facilities where vermiculite ore from Libby, Montana, was processed
- Demolition workers
- Workers at asbestos product manufacturing plants
- Auto mechanics
- Boilermakers
- Bricklayers
- Building inspectors
- Carpenters
- Drywallers
- Electricians
- Floor covering manufacturers or installers
- Furnace workers
- Glazers
- Grinders
- Hod carriers
- Insulators
- Iron workers
- Laborers
- Longshoremen
- Maintenance workers
- Merchant marines
- Millwrights
- Operating engineers
- Painters
- Plasterers
- Plumbers
- RoofersIndividuals

Who have worked in the above work environments and occupations should consult with a physician with expertise in the evaluation and management of asbestos-related lung disease.

B. Other Causes
resource: medcine health

1. Radiation : Mesothelioma has been reported to occur in few people following exposure to therapeutic radiation using thorium dioxide (Thorotrast).

2. Zeolite : Zeolite is a silicate mineral (chemically related to asbestos) commonly found in the soil of the Anatoli region of Turkey. A few cases of mesothelioma reported from this region may have been caused by zeolite.

3. Simian Virus 40 (SV40) : The role of SV40 in the development of mesothelioma has also been suggested. This virus has been identified in human mesothelioma cells. In studies conducted in animals, it has been shown to induce the development of mesothelioma. However, further research is needed to confirm the link.

4. Smoking : the combination of smoking and asbestos exposure significantly increases a person's risk of developing pleural mesothelioma.

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