November is lung cancer awareness month, a time to learn about one of the most common and deadly forms of cancer. Although the disease is often associated with smoking, according to the American Cancer Society, as many as 20 percent of people who die from lung cancer in the U.S. each year have never used a tobacco product. Here are three ways you can develop the disease even if you’ve never touched a cigarette.

Environment

Environmental factors play a major role in your individual lung cancer risk, and according to the U.S. Environmental Protection Agency, radon gas is the leading cause of lung cancer in nonsmokers. Radon is a colorless, odorless radioactive gas that forms naturally as a result of the decay of radioactive elements such as uranium.

According to the American Cancer Society, people can be exposed to radon in homes or buildings constructed on soil or rock high in radioactive characteristics. The gas given off by the soil or rock can then enter a building through cracks in the walls or foundation. For this reason, people who spend time in their basement or in the lowest level of a building will have the greatest risk of radon exposure.

Lifestyle

Although non-smokers have already significantly decreased their risk of lung cancer, they could be unknowingly increasing their risk with lifestyle. For example, spending a large amount of time in areas where they are exposed to secondhand smoke can seriously increase that risk.

In addition, while there is a direct link between an unhealthy diet and increased lung cancer risk, research has shown that eating a healthy diet filled with fruit and vegetables may protect against lung cancer in both smokers and nonsmokers, The American Cancer Society reported.

Genetics

Some individuals have a genetic predisposition to lung cancer. According to The American Cancer Society, some specific genetic mutations are actually more common in non-smoking lung cancer patients than smokers.

In addition, according to the Cancer Treatment Centers of America, individuals with an immediate family member who has or had lung cancer (and who does not or did not smoke) may be more prone to developing the disease.

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