Mesothelioma Risk Factors

While there is only one known cause of mesothelioma (asbestos), there are multiple risk factors that can increase a person’s chance of contracting it. Knowing what these risk factors are can help protect you and your at-risk loved ones from developing mesothelioma, or at least prevent speeding up its progression.

Mesothelioma Risk Factors Overview

When it comes to your health, the more you know, the better you can improve it and manage your health care. Even if you are diagnosed with, or at risk for a disease as serious as mesothelioma, this fact remains true.

Understanding exactly what mesothelioma is, its causes, risk factors, symptoms, progression, prognosis, and treatment will only help you navigate your specific situation more confidently and successfully.

It’s important that you share any of your known risk factors (such as occupational history) with your doctor so that they can better assess and diagnose your condition.

But first, it is important to understand the difference between a cause and a risk factor.

Cause vs Risk Factor

A cause of a disease, or cancer like mesothelioma, is something that absolutely precedes the disease and is definitely proven to directly result in its development. It’s a condition, event, or substance that, if absent, would prevent the disease from ever having developed.

A risk factor, on the other hand, is something that is associated with the disease but does not directly cause it.

A risk factor is a correlation, not a causality. A risk factor can be something that makes someone more susceptible to disease but doesn’t directly cause the disease. It can also be something that purely coincides with the disease, such as age or socio-economic class.

Known Causes of Mesothelioma

As far as mesothelioma is concerned, the only known cause, as well as the highest risk factor, is asbestos. When asbestos fibers are inhaled and travel into the lungs or are swallowed and pass through the digestive system, they can stick in the tissue of the lung (pleural), the chest (pericardial) or abdominal (peritoneal) cavities.

As the asbestos fibers resist digestion and eradication by the body, they remain there over years and decades, causing inflammation and scarring. As a result, they can (but do not always) disrupt cell development and cause cancer to develop.

Asbestos exposure does not guarantee that a person will develop mesothelioma. In fact, mesothelioma is still relatively rare, even among those exposed to asbestos.

Risk Factors for Mesothelioma

While asbestos is the only known cause of mesothelioma, there are some possible risk factors that can increase a person’s chance of developing it after being exposed to asbestos.

Knowing the risk factors can play an important role in preventing mesothelioma since not everyone exposed to asbestos develops it. It’s a rare cancer, even among those who have been exposed to asbestos, so if you have been exposed, avoiding risk factors can improve your chances of not developing mesothelioma.

Even if you have developed mesothelioma, avoiding additional risk factors can prevent it from progressing more quickly.

Why some develop mesothelioma after asbestos exposure while others do not is still not fully understood among the mesothelioma community. It’s possible that risk factors play a major role in influencing who does and does not develop it, which is all the more reason to be fully aware of what the risks are so that you can avoid them.

Asbestos Exposure

As mentioned above, asbestos is the main risk factor, as well as the only known cause of mesothelioma. Those exposed to it, either through primary or secondary exposure, are the only ones at risk for contracting mesothelioma.

However, the extent of a person’s asbestos exposure, as well as the type of asbestos they encounter, play a role in determining the severity of their risk.

While no amount of asbestos exposure is safe, the following factors influence the risk level:

  • Concentration: The amount of asbestos a person is exposed to at one time
  • Duration: The length of time someone is exposed to and breathing in asbestos at a given time
  • Frequency: The number of times a person is exposed to asbestos over their lifetime
  • Asbestos type: Asbestos can be categorized into two main types, serpentine, and amphibole. Serpentine asbestos fibers are long and curly, while amphibole fibers are short and straight, rather like needles.

Studies demonstrate that exposure to amphibole asbestos fibers results in higher risk for mesothelioma than exposure to serpentine fibers.

Occupations where individuals were/are exposed to asbestos in higher concentrations, longer duration or on more frequent occasions pose higher risks than those with minimal exposure.

Occupations with the highest risk for dangerous levels of exposure include:

  • Construction workers
  • Shipyard workers
  • Power plant workers
  • Firefighting/first responders
  • Automotive technicians

Lower-to-moderate-risk occupations include:

  • Metalworkers
  • Plumbers
  • Carpenters
  • Electricians

Besides the above factors, whether someone has direct or secondary contact with asbestos can also play a role in their level of risk for mesothelioma. Those who encounter and breathe in asbestos directly experience primary exposure.

But those who encounter primary exposure often carry asbestos fibers with them on their clothes, hair, and skin into their homes, resulting in secondary exposure for their loved ones who can breathe in the fibers they bring home.

Primary exposure poses a higher risk of mesothelioma than secondary exposure. However, both types of exposure have produced cases of mesothelioma.


Admittedly, there is much debate and conflicting information regarding the impact smoking has on the development of mesothelioma. Some studies indicate that smoking does increase one’s risk of developing mesothelioma.

However, smoking undeniably damages the lungs and suppresses the immune system, both of which make an individual susceptible to cancer and disease, including mesothelioma.

Furthermore, studies have proven that those who have asbestos exposure and smoke are far more likely to develop lung disease and cancer than those exposed to only asbestos or only smoking.

Evidence suggests that asbestos-exposed smokers are in greater danger of developing mesothelioma than non-smokers with asbestos exposure.

Doctors strongly urge everyone exposed to asbestos or those with a mesothelioma diagnosis to quit smoking.

Regardless, the risks smoking poses to those exposed to asbestos is well established. Doctors firmly recommend quitting smoking if you have mesothelioma or if you were exposed to asbestos since your chances of developing lung cancer become even greater than the individual risks of either asbestos exposure or smoking combined.


Some studies suggest that those exposed to high amounts of radiation after asbestos exposure were more likely to develop mesothelioma. This was especially true for those who received high doses of radiation to the abdomen or chest while treating another type of cancer. However, even in these patients, mesothelioma remained a rare occurrence.

Patient Demographics

Certain demographics face a much higher risk for mesothelioma than others. White males over the age of 45, typically 65 and older, are most at risk.

As noted above, these risk factors do not actually cause cancer. The reason mesothelioma is so common among this population is because far more white males worked in high-risk occupations than either women or men of other races.

The reason mesothelioma typically develops in later years is because of the cancer’s latency—it takes anywhere from 20-50 years for mesothelioma to develop after initial exposure to asbestos. Furthermore, the worst levels of exposure occurred before regulations were established in the 1980s.

Mesothelioma is far more common in individuals in their mid-to-late 40s or older who worked in high-risk occupations prior to the 1980s.

BAP1 Gene Mutation

Another potential risk factor is having the BAP1 gene mutation. This is a rare mutation of a gene that, under normal circumstances, helps to limit cell growth and can suppress cancer development. The mutation of the BAP1 gene means that this cancer-fighting cell cannot operate correctly, thus leaving the individual with an increased risk for cancer development.

It does appear that those exposed to asbestos who have the BAP1 gene mutation are indeed at greater risk for developing mesothelioma than those who do not have the gene mutation.

SV40 Virus

A final possible risk factor, and even a potential cause, may be the simian virus 40 (SV40).

This SV40 virus accidentally made its way into a group of injectable polio vaccines administered from 1955 to 1963. Approximately 30 million people in the U.S. were subsequently exposed to SV40.

The reason some consider it a possible risk factor or even cause for mesothelioma is because of limited lab studies where lab animals infected with SV40 developed mesothelioma. Other tests demonstrated SV40 causing mouse cells to develop cancer; when exposed to asbestos, the cancer-causing effect of SV40 increased.

In humans, there have been instances of SV40 found in those who died from mesothelioma. Beyond this, however, nothing has been shown or proven. SV40 has also been found in humans who developed no cancer, and no major studies have been able to prove an increased risk of mesothelioma among those vaccinated with the contaminated polio injections.

However, because mesothelioma has such extreme latency, taking 10-50 years to develop after initial exposure, and because it typically develops between the age of 50-70, some argue that a connection might not be able to be accurately determined until those vaccinated reach the peak at-risk age.

Seeking Mesothelioma Support

If you were exposed to asbestos throughout your career and you’ve since developed mesothelioma, you may be struggling to cope with grief and trauma associated with your condition.

Our Patient Advocates are available to assist you and your family in dealing with your diagnosis. From connecting you with emotional and financial support to matching you with the right specialist for your diagnosis, our Patient Advocates are standing by to help you now.

Mesothelioma Support Team

Mesothelioma Hope was founded by a team of advocates to educate people about this aggressive form of cancer. Mesothelioma affects thousands of people each year. We help give hope to those impacted by mesothelioma.

View 6 References
  1. ASCO Cancer.Net, “Mesothelioma: Risk Factors” Retrieved from: Accessed on February 9, 2018.
  2. American Cancer Society, “What Are the Risk Factors for Malignant Mesothelioma” Retrieved from: Accessed on February 9, 2018.
  3. Moffitt Cancer Center, “Mesothelioma Risk Factors” Retrieved from: Accessed on February 9, 2018.
  4. University of Rochester Medical Center, “Malignant Mesothelioma: Risk Factors” Retrieved from: Accessed on February 9, 2018.
  5. American Lung Association, “Mesothelioma Symptoms, Causes and Risk Factors” Retrieved from: Accessed on February 9, 2018.
  6. Canadian Cancer Society, “Risk factors for mesothelioma” Retrieved from: Accessed on February 9, 2018.

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