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Mesothelioma Causes & Risk Factors

Expert Fact Checked

This page was medically reviewed by James Stevenson, M.D.. For information on our content creation and review process read our editorial guidelines. If you notice an error or have comments or questions on our content please contact us.

James Stevenson, M.D. Thoracic Medical Oncologist

Mesothelioma is caused by exposure to asbestos. Once inhaled, tiny asbestos fibers can damage organ linings and cause mesothelioma cancer. Asbestos was used in military and commercial settings for decades. Other mesothelioma risk factors include advanced age and radiation exposure.

What Is the Main Cause of Mesothelioma?

The only confirmed cause of mesothelioma is asbestos exposure. When tiny asbestos fibers become airborne, people might inhale or ingest them. The fibers can then settle in and damage organ linings, leading to mesothelioma. Asbestos fibers commonly lodge in the lining around the lung (the pleura). They may also settle in other areas, like the abdominal lining (the peritoneum).

For many years, product makers used asbestos in commercial and consumer goods. This exposed workers and the general public to serious health risks. According to the World Health Organization, asbestos causes about 70% of work-related cancer deaths.

No amount of asbestos exposure is considered safe. Even short-term exposures can cause mesothelioma or other asbestos-related diseases.

“Mesothelioma is a very rare type of cancer arising from a tissue in the body called the mesothelium, a thin, almost transparent sheet of tissue that surrounds some internal organs. It is unique among cancers in being so linked to environmental exposure, in this case asbestos.”

Dr. F Perry Wilson

Francis Perry Wilson, M.D.

Senior Medical Advisor

How Does Asbestos Cause Mesothelioma Cancer?

Experts do not know exactly how asbestos causes mesothelioma. But they suggest the following events may lead to the cancer:

  • Exposure: An individual inhales or ingests asbestos fibers.
  • Embedding: The fibers embed in thin tissue linings made of mesothelial cells – for example, the lining around the lungs (pleura).
  • Inflammation: The fibers cause inflammation where they settle.
  • Cell damage: Over time, inflammation leads to damage and cancerous changes in the mesothelial cells.
  • Cancer: As a result, these changes cause mesothelioma to develop.

How Do You Get Mesothelioma?

Graphic depicting the events that cause mesothelioma: Asbestos fibers enter the lungs, then settle in the linings around the lungs. The asbestos fibers irritate the cells in the area, which changes the cells over time, leading to cancer.

It can be a long time between initial asbestos exposure and when symptoms of mesothelioma become apparent. Mesothelioma has a latency period of 10 – 50 years.

Does Anything Other Than Asbestos Cause Mesothelioma?

Research shows nearly all mesothelioma cases — about 90% — are linked to asbestos. Occasionally, doctors can’t trace a patient’s asbestos exposure. That doesn’t mean the patient was never exposed. It could be that the patient encountered asbestos in a way they can’t remember.

A very small number of cases may be related to a specific kind of genetic mutation. But the vast majority of mesothelioma patients don’t have this mutation.

Can Smoking Cause Mesothelioma?

Data from over 40 years of research indicates smoking does not cause mesothelioma. To determine this, doctors looked at large groups of people who were exposed to asbestos. They counted cases of mesothelioma that occurred in people who did or did not smoke. The smokers had the same risk of mesothelioma as the non-smokers.

Which Factors Increase the Risk of Mesothelioma?

Data indicates nearly all mesothelioma tumors are caused by asbestos. But other factors may also increase your risk.

Risk factors for mesothelioma include:

*These are general risk factors for cancer.

Long-Term Asbestos Exposure Increases Risk

People who live or work near asbestos for long periods of time have a higher risk of developing mesothelioma. Experts say risk increases as the duration of exposure goes on. Someone who lived near natural asbestos for 6 months would have less risk than a person who worked with it for 10 years.

Long-term asbestos exposure happens most often with asbestos jobs. Many people who worked in manufacturing or the military have had serious exposures. Dangerously lengthy exposure can also happen to anyone who lives near natural asbestos.

Workplace Exposure

The most common way people encounter asbestos is through exposure at work. Before stricter regulations, many workers directly handled asbestos. Others used asbestos-containing materials to do their jobs. Construction workers, shipyard employees and others may still run into asbestos at work.

Military Exposure

About 30% of mesothelioma diagnoses occur in veterans. This stems from the military’s widespread use of asbestos for most of the 20th century. Asbestos has been phased out, but older materials and structures still contain it. Current service members may still be at risk of exposure from these sources.

Secondary Asbestos Exposure

Secondary asbestos exposure happens when someone accidentally carries asbestos on their person. For example, the tiny fibers may settle on a worker’s clothing. Anyone who comes into contact with these clothes might inhale or ingest asbestos. This type of exposure can cause mesothelioma.

“When I was a girl, I wore my dad’s work coat all the time. It was covered in asbestos from his construction job.”

Heather Von St. James is a mesothelioma survivor and advocate.

Heather Von St. James

developed pleural mesothelioma from secondary asbestos exposure.

Environmental Exposure

Asbestos occurs naturally in the environment around us. People who live near natural asbestos deposits are at risk of exposure and illness. For example, Libby, Montana, is situated near a former asbestos mine. Its residents experienced historically high rates of asbestos cancers, including mesothelioma.

If you suspect any type of asbestos exposure, speak with your doctor. Together, you can come up with a plan to monitor for potential signs of asbestos conditions.

Increased Mesothelioma Risk Among Older Patients

One common misconception is that mesothelioma only strikes the elderly. The most recent data from the Centers for Disease Control and Prevention (CDC) indicates risk increases with age. Nearly 80% of mesothelioma cases occur in people 65 years or older. But mesothelioma is diagnosed in younger patients, too.

According to the CDC’s most updated statistics, in the span of a single year:

  • Fewer than 60 mesothelioma cases were diagnosed in patients younger than 45.
  • More than 2,200 mesothelioma cases were diagnosed in patients older than 65.

This means people 65 and older have more than 44 times the risk of mesothelioma compared to those 45 and younger. Mesothelioma can take many years to develop after asbestos exposure. This latency period may contribute to elevated risk with increasing age.

Greater Mesothelioma Incidence Among Men

Mesothelioma is not gender-specific but does occur most often among men. Data indicates pleural mesothelioma is diagnosed at least twice as often in men than women.

This difference may be because more men work in asbestos industries. Historically, many asbestos occupations, like mining and working in shipyards, have more male employees than female.

Health and Lifestyle Risk Factors

Several health and lifestyle factors may increase a person’s risk of developing cancer, including:

  • Alcohol consumption: Research suggests someone who regularly drinks alcohol has an increased risk of cancer. The more a person drinks, the higher the risk.
  • Eating certain foods: Research suggests some foods may elevate the risk of cancer. These include cooked, starchy foods — like French fries — and meats cooked at high temperatures.
  • Lack of physical activity: Data suggests higher levels of physical activity may decrease the risk of some cancers. This may mean that sedentary lifestyles increase the risk of cancer.
  • Obesity: Research suggests obesity may carry a greater risk of cancer. But this risk may result from other factors related to obesity. For example, underlying conditions may be causing obesity. Those conditions, not obesity, may increase the risk of cancer.

Any of these may increase the risk of developing mesothelioma or other cancers after asbestos exposure. Other lifestyle choices, like smoking tobacco, may affect cancer risk too.

Other Mesothelioma Risk Factors

Some research shows there are other potential mesothelioma risk factors. These include the SV40 virus and exposure to radiation or erionite. Certain inherited genes may also play a role.

Inherited BAP1 Gene Mutations

  • BAP1 mutation is linked to developing mesothelioma at a younger age.
  • People born with this mutation tend to develop cancer easily.
  • Mesothelioma patients with this mutation may have better life expectancy than those without it.

Simian Virus 40 (SV40)

  • Testing has found evidence of previous SV40 infection in some pleural mesothelioma patients.
  • The link between SV40 and mesothelioma is still disputed.
  • Research is ongoing.

Radiation Exposure

  • Radiation exposure may increase the risk of developing mesothelioma.
  • Radiation exposure may occur with certain cancer treatments, X-rays or atomic energy work.

Erionite / Zeolites

  • Erionite is part of a mineral group called zeolites. It is often found in volcanic ash.
  • Some geographic areas with high levels of erionite also have high rates of mesothelioma.

If you have any of these risk factors, you should discuss them with your doctor. This can help you understand possible ways to lower risks. And the doctor can help you watch for potential symptoms of asbestos illnesses.

How Can You Prevent Malignant Mesothelioma?

The simple truth is no action can guarantee that any one person won’t get mesothelioma. But avoiding asbestos is the best way to lower your risk. Simple steps can help you minimize potential asbestos exposures.

  • Be aware of past asbestos uses. Humans can’t see asbestos fibers without a microscope. But you can learn where you might find asbestos products and materials. To reduce risks, it’s best to avoid any items that may contain this dangerous mineral.
  • Follow asbestos safety protocols at work. Protective actions and equipment are vital for anyone working at an asbestos jobsite. Experts recommend correctly wearing personal protective equipment. This includes following all decontamination steps.
  • Trust asbestos professionals to handle suspicious materials. Older buildings can harbor asbestos materials. This includes homes and schools built before the 1980s. Renovation projects can disturb the asbestos and put people at risk. But an asbestos inspector can check these structures ahead of time. This step helps reduce the risk of exposure from older asbestos products.
  • Know the law. The Environmental Protection Agency (EPA) recently banned ongoing uses of one type of asbestos. But the United States still lacks a full asbestos ban. So asbestos products still remain in many older buildings and homes. Staying mindful of this can help you keep a distance from any suspicious materials.

Common Questions About Mesothelioma Causes

  • Who is at risk for mesothelioma?
    People who experience frequent, long-term asbestos exposure are most at risk for developing mesothelioma. In general, regular exposure to asbestos is most common at asbestos jobsites. Certain occupations, like construction workers, shipyard workers and veterans, face a higher risk of exposure.
  • How easy is it to get mesothelioma?
    No amount of asbestos exposure is considered safe. Regular, long-term exposure to asbestos puts individuals at a higher risk of developing mesothelioma. But even one-time or short-term exposure may cause mesothelioma and other asbestos illnesses.
  • Can you sue for asbestos exposure from negligence?
    Under certain conditions, you can sue liable parties for asbestos exposure. For example, you may be able to sue your workplace if they failed to protect you from asbestos and you develop health conditions as a result.