Being Well

Lung Cancer in Nonsmokers: Causes and Prevention

Exposure to cancer-causing agents in the air can lead to lung cancer, even in people who don't smoke.

We often associate lung cancer with smoking, so it may be surprising when someone who has never smoked or used any tobacco products gets diagnosed with lung cancer. Unfortunately, lung cancer in nonsmokers may be more common than we think. The American Cancer Society estimates that up to 20 percent of lung cancer deaths are from causes unrelated to smoking.

Causes of Lung Cancer in Nonsmokers

Living with someone who smokes raises your risk of lung cancer. But even people without any prolonged firsthand or secondhand exposure to tobacco smoke can develop this type of cancer. Here are the top causes of lung cancer in nonsmokers:

1. Radon gas

Exposure to radon gas is the top cause of lung cancer in nonsmokers. Radon occurs naturally when uranium, thorium and radium decay in rocks and soil.

The National Cancer Institute reports everyone is exposed to low levels of radon every day. But about one in 15 homes has a radon level above what the Environmental Protection Agency (EPA) considers safe. The gas seeps into the air through cracks in the foundation, floors or walls. It can also come from groundwater or well water and can be inhaled when you shower or bathe. Long-term exposure to radon gas has been linked to lung cancer even in nonsmokers.

2. Exposure to carcinogens at work

Asbestos is the most common workplace substance known to cause lung cancer, according to Mayo Clinic, but people exposed to arsenic, chromium and nickel are also at higher risk. Although employers have taken steps to protect workers and asbestos is much less common than it used to be, employees still need to be cautious about their exposure to harmful substances.

3. Outdoor air pollution

The World Health Organization has classified outdoor air pollution as carcinogenic (cancer-causing) to humans and has identified it as a cause of premature deaths from lung cancer. Air pollution is more concerning in countries outside the United States with less stringent standards for air quality.

4. Genetics

People with a close relative who had lung cancer are at higher risk of developing it themselves. Researchers are still trying to understand genetic links to lung cancer.

Prevention Tips

With each of the causes of lung cancer in nonsmokers, you can take steps to protect yourself. The first step is to never smoke and limit exposure to secondhand smoke. Smoking, along with other risk factors, further increases your chances of developing lung cancer. You can also take steps to address each risk individually.

  • Test your home for radon. Radon tests are inexpensive and tell you the long-term and short-term levels of radon in your home. The EPA recommends taking action if your reading is above 4 picocuries per liter (pCi/L) of air. You can seal your home or increase ventilation to reduce the levels of radon gas.
  • Protect yourself at work. Use the proper equipment to reduce exposure to cancer-causing substances and avoid them whenever possible.
  • Exercise and eat healthy. No matter what risk factors you’re exposed to, maintaining a healthy diet rich in fruits and vegetables and exercising regularly can help lower your risk of developing not only lung cancer, but also many other cancers.

According to Mayo Clinic, lung cancer often doesn’t cause any symptoms in its earliest stages. See your doctor if you feel that you have risk factors for lung cancer even if you don’t smoke. Your doctor can talk to you about screening options to detect cancer early and other steps you can take to prevent cancer from developing.

If you think you're at risk of developing lung cancer, talk to your doctor to learn more about screening and prevention.

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Patricia Chaney
Patricia Chaney