Mesothelioma Causes & Risk Factors
Mesothelioma is caused by inhaling or ingesting asbestos fibers. The asbestos fibers can travel into the lungs or abdomen and lodge in the mesothelium, a protective membrane that covers the organs. Mesothelioma occurs as a result of inflammation and damage to cells and DNA, causing tumors to develop decades after asbestos exposure.
Watch: Learn what causes mesothelioma from thoracic surgeon Dr. Marcelo DaSilva.
How Do You Get Mesothelioma?
The primary cause of mesothelioma is asbestos. About 80% of mesothelioma patients were exposed to asbestos in the past. Malignant mesothelioma develops when inhaled asbestos fibers cause irreversible inflammation, scarring and cell damage.
All types of asbestos cause mesothelioma.
When asbestos fibers travel to different parts of the body, it results in different types of mesothelioma.
For example, pleural mesothelioma is caused when fibers get stuck in the pleura, which is the lining of the lungs. The peritoneal type is caused when fibers are deposited in the peritoneum, which is the lining of the abdominal cavity.
Mesothelioma was virtually unknown until the 20th century. Mesothelioma incidence rates rose as industries expanded the use of asbestos.
Risk Factors for Mesothelioma
The majority of people who get malignant mesothelioma cancer were exposed to asbestos while working certain blue-collar jobs or serving in the military. About 80% of people diagnosed with mesothelioma have been exposed to asbestos.
Primary Mesothelioma Risk Factors
- Working at an asbestos mine or asbestos-processing plant
- Working in a high-risk occupation such as construction or heavy industry
- Serving on military ships or facilities built with products containing asbestos
- Living in a residential area near an asbestos mine or contaminated site
- Disturbing asbestos products during a home renovation without proper safety measures
Watch: Dr. Jacques Fontaine talks about the different people who are at risk of developing mesothelioma.
Occupational Asbestos Exposure
The primary risk factor of mesothelioma cancer is occupational asbestos exposure. Construction workers and demolition crews are among the highest at risk due to the thousands of construction materials manufactured with asbestos before the 1980s. These materials are still present in millions of homes and commercial buildings today.
Firefighters have a high risk of asbestos exposure for similar reasons. When fires or natural disasters destroy homes and damage structures, firefighters are among the first people exposed to the toxic fibers released into the air.
Historically, industrial workers, power plant workers and shipyard crews also risked exposure from asbestos-containing materials in their fields.
Environmental Asbestos Exposure
Asbestos is a naturally occurring group of minerals that form in large deposits. People who live in hilly or mountainous regions risk exposure from asbestos that might naturally release from the earth.
As the mineral mixes with nearby water sources, it can contaminate residential wells and drinking supplies. Asbestos that enters bodies of water can also evaporate and travel as airborne fibers for several miles, polluting residential areas.
Gender
Research has shown that mesothelioma incidence is higher among men, but it’s unknown whether there is a genetic component to the disease. The higher prevalence in men may be due to the trend of male-dominated occupations with asbestos risk.
Additionally, patients with mutations in BAP1, a tumor-suppressor gene, have an increased likelihood of developing mesothelioma after exposure to asbestos.
Age
Age does not directly impact the risk of developing mesothelioma. However, the average age of mesothelioma patients is 69 due to the latency period of the disease. Mesothelioma can take 20 to 50 years to develop after initial asbestos exposure. While older adults are more likely to develop mesothelioma, age itself is not a risk factor.
Lifestyle
Good overall health can help lower the risk of cancer and minimize the side effects of treatment. Healthy habits such as adequate sleep and proper nutrition may also improve a mesothelioma prognosis. Lifestyle factors do not directly affect the risk of developing mesothelioma, but they can affect overall patient survival and treatment options.
Simian Virus 40 (SV40)
In some studies, researchers have identified a possible link between the simian virus 40 and mesothelioma. SV40 was present in contaminated polio vaccines between the 1950s and 1960s, affecting an estimated 10 million to 30 million people.
Current evidence suggests that exposure to SV40 alone is insufficient to cause mesothelioma in humans. However, the virus may contribute to an elevated risk of mesothelioma in patients exposed to other carcinogens, such as asbestos. More studies are required as researchers have not yet confirmed a definite relationship between SV40 and mesothelioma in humans.
Radiation
There is evidence to suggest a correlation between some sources of radiation and mesothelioma development. Radiation treatment for other cancers, such as lung or abdominal cancers, may increase the risk of developing mesothelioma. Specific genetic markers may also contribute to this risk, but more research is required.
Zeolites
Erionite, a mineral in the zeolite family formed by volcanic ash and similar to asbestos, has been proven to cause mesothelioma cancer and other respiratory diseases. Erionite is predominant in the Western United States throughout gravel quarries and areas of road construction.
Zeolites are mostly harmless while in the ground until a disturbance releases the fibrous mineral into the air. The National Institute for Occupational Safety and Health has begun to recommend erionite regulations, similar to asbestos directives. Exposure poses a severe risk of mesothelioma in certain erionite-rich regions, such as Turkey.
Is Smoking Tobacco a Risk Factor for Mesothelioma?
Smoking on its own does not increase the risk of developing mesothelioma. However, in combination with asbestos exposure, it can increase the risk of developing mesothelioma and lung cancer.
Cigarette smoking damages structures in the lungs that aid in removing debris and promoting airflow. Over time, mucous, cellular waste and toxins such as asbestos can build up. This debris can cause decreased oxygen and cellular damage that leads to mesothelioma and other cancers.
Where Does Asbestos Exposure Occur?
Asbestos exposure primarily happens in a workplace setting. It can also happen at home and in the natural environment.
Asbestos was widely used in thousands of commercial, industrial and domestic products. Examples include drywall, insulation, piping, glues and adhesives, ceiling tiles, cement and shingles.
Workers who manufactured or used these products were exposed to asbestos on the job. Others, including workers’ family members, faced secondary exposure at home. Environmental exposure happened in communities that mined or processed asbestos.
Past Occupational Asbestos Exposure
The risk for asbestos-related illnesses is highest for people who worked with the raw mineral or with asbestos-containing products on a daily basis.
High-Risk Occupations for Mesothelioma Cancer
- Shipyard workers
- Construction workers
- Power Plant workers
- Chemical Plant workers
- Industrial workers
- Insulators
- Boiler workers
- Auto mechanics
Mesothelioma Risk Factors in Present-Day Jobs
Construction tradesmen and firefighters can be exposed to asbestos while working in old homes and structures built with contaminated materials. Exposure can happen during a renovation, demolition or disaster response.
When old buildings are destroyed without safety precautions, airborne asbestos fibers can contaminate the surrounding area. Even new buildings contain asbestos products such as roofing materials.
Firefighters, contractors, demolition workers, electricians and plumbers are at high risk of exposure to asbestos in old buildings.
Secondhand Exposure to Asbestos
When the asbestos industry was booming, families of workers were also at great risk. Workers often came home with asbestos fibers on their hair, work clothes, shoes and tools. This exposed family members to the toxic substance and increased their risk for mesothelioma and related diseases.
Environmental Asbestos Exposure
Because asbestos is a naturally occurring mineral, people living near large deposits in hilly or mountainous regions also face exposure. Minimal amounts of the mineral can fill the air in these regions. Still, environmental exposure is most dangerous near former asbestos mines.
My father worked in steel mills for years and I remember washing his clothes which were covered in dust.Judy GoodsonDiagnosed with peritoneal mesothelioma in 2013
How Does Mesothelioma Develop?
Mesothelioma can develop as a result of DNA damage caused by asbestos fibers.
Once asbestos is inhaled, the body has a hard time getting rid of the fibers.
The fibers become lodged in tissues and accumulate with repeated exposure. After many years, these fibers may cause cancerous changes to surrounding cells.
Mesothelioma starts in mesothelial cells, which make up the protective membranes of the mesothelium that cover the lungs, abdomen and heart.
Watch: Learn how mesothelioma can develop on different parts of the body from mesothelioma specialist Dr. Marcelo DaSilva.
DNA Damage Caused by Asbestos Fibers
- Inflamed Cells: Fibers inflame and irritate mesothelial cells, leading to irreversible scarring, cellular damage and cancer.
- Genetic Changes: Fibers enter mesothelial cells and disrupt their life cycle, causing genetic changes that lead to cancer.
- Cancerous Mutations: Asbestos causes the production of free radicals, which are molecules that damage DNA and cause healthy cells to mutate.
- Uncontrolled Growth: The fibers trigger the production of oncoproteins, which block genes that protect cells from growing uncontrollably and forming tumors.
Other Mesothelioma Risk Factors
- Exposure to other fibrous minerals such as erionite.
- Exposure to radiation.
- Receiving a polio vaccine between 1955 and 1963 that was contaminated with simian virus 40 (SV40).
- Genetic factors that increase the likelihood of developing cancer.
A 2020 Chinese study published in Toxicology Letters exposed rats to chrysotile asbestos fibers in order to observe how the fibers affected the lungs. Results showed that chrysotile fibers caused lung inflammation, lung tissue damage and activated genes associated with cancer growth.
Differences Between Mesothelioma Causes & Risk Factors
A risk factor is anything that increases the odds of developing a disease. A cause is the contributing factor that leads to a disease.
For example, although men are much more likely to develop mesothelioma than women, gender alone cannot cause the cancer.
Often, multiple risk factors are involved in the development of mesothelioma.
The duration of asbestos exposure plays a role. While the World Health Organization says no amount of asbestos exposure is safe, it is usually heavy, repeated exposure over many years that leads to asbestos-related illnesses.
A study in the American Journal of Epidemiology found the longer someone works in a job that involves asbestos exposure, the higher their risk of mesothelioma becomes.
| Years of Occupational Asbestos Exposure | Increase in Risk of Mesothelioma |
|---|---|
| 1-7 | 1.7 times more likely |
| 8-19 | 2 times more likely |
| 20+ | 5.4 times more likely |
The link between asbestos exposure and mesothelioma is so strong that it can be difficult for researchers to tell if any other risk factors can cause mesothelioma on their own. Although scientists continue to study this topic, and they know other fibrous minerals cause mesothelioma, exposure to asbestos remains the most clearly defined cause.
Preventing and Detecting Mesothelioma
The best way to prevent mesothelioma is to follow workplace safety regulations and protect yourself by learning more about how you might be exposed to asbestos at work and at home. Be cautious of materials in old homes that may contain asbestos.
If you think a past job or home repair project exposed you to asbestos, you should seek regular medical exams to check for signs of asbestos-related diseases.
If you or a loved one has a history of asbestos exposure — especially in the workplace — don’t wait for symptoms to arise. Instead, be proactive and talk to your doctor. Early detection offers the best opportunity for effective mesothelioma treatment.
Common Questions About Mesothelioma Causes
- Is asbestos the only cause of mesothelioma?
According to the American Cancer Society, 80% of mesothelioma cases are caused by known exposure to asbestos. Studies have shown that radiation treatment for other cancers or certain genetic markers may increase the risk of developing mesothelioma. However, asbestos remains the only proven cause of the disease.
- Who is at risk for mesothelioma?
Occupational asbestos exposure is the primary cause of mesothelioma. Construction workers, firefighters, industrial workers, power plant workers and shipyard workers have the greatest risk of asbestos exposure.
Wives and children of blue-collar workers are at risk of secondary asbestos exposure and mesothelioma. Men who worked with asbestos would often carry fibers home on their skin, hair, clothes and tools.
- How much exposure to asbestos is harmful?
There is no safe amount of exposure to asbestos due to the size and shape of asbestos fibers. The risk of developing mesothelioma is greater with increased exposure to asbestos. Trace amounts of asbestos on clothes and skin are enough to cause mesothelioma by secondary exposure.
- What should I do if I think I am developing mesothelioma?
If you are experiencing respiratory symptoms or other signs of mesothelioma and have a history of asbestos exposure, talk with your physician about being screened for the disease.
Mesothelioma doctors will order CT imaging and other tests based on your history of asbestos exposure to determine if you are developing mesothelioma.
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