November is Lung Cancer Awareness Month, and it serves as a reminder that the disease is the most common cancer death in the United States, killing an estimated 158,080 people every year.
While smoking causes an overwhelming 80 percent of lung cancer deaths, it is important to know other risk factors exist. In fact, many people diagnosed with the disease never smoked in their lives.
For example, exposure to asbestos, a carcinogen directly linked to mesothelioma, can also lead to lung cancer.
While not everyone who smokes will be diagnosed with lung cancer, smoking can negatively interact with some of these other risk factors, placing smokers at an even higher risk of developing the deadly condition.
Five Lesser-Known Causes of Lung Cancer
It’s common knowledge that smoking and secondhand smoke increases the likelihood of developing lung cancer and other respiratory illnesses, but lung cancer — especially among nonsmokers — is linked to asbestos exposure, air pollution, exposure to radon, silica and genetic changes.
This colorless, odorless and easily inhaled radioactive gas is the second most common cause of lung cancer in the U.S.
Radon can be found in homes, offices, schools and other buildings, as well as underground water and surface water. It forms naturally from the decay of radioactive elements in soil and rock throughout the world.
The gas breaks down into tiny radioactive elements — called radon progeny — that can lodge in the lining of the lungs. These elements emit radiation that can damage the lungs, eventually leading to lung cancer. Radon exposure most often occurs at job sites, such as underground mining, but exposure also happens in homes, schools and offices when the gas escapes the soil or rocks through cracks in the floors, walls, construction joints or gaps in the foundation.
It’s responsible for an estimated 20,000 annual lung cancer deaths in the U.S. Smokers exposed to radon are at higher risk of developing the disease.
Asbestos exposure is the leading cause of mesothelioma, a cancer that forms in the lining of the lungs or abdomen, but the toxic mineral can also cause lung cancer.
Both diseases take decades to develop, have overlapping symptoms and share many of same diagnostic procedures and treatment options. But each cancer grows differently and occurs in different areas of the body.
The National Cancer Institute confirmed asbestos as a cause of lung cancer in 1942. Asbestos-related lung cancer accounts for an estimated 4,800 deaths each year — that’s 4 percent of all lung cancer deaths.
When inhaled, asbestos fibers can become trapped in the lungs, eventually leading to inflammation, scarring and, in some cases, lung cancer. Smoking does not increase the risk of mesothelioma, but exposure to asbestos greatly increases the risk of lung cancer in smokers.
The World Health Organization classifies outdoor air pollution (diesel engine exhaust, solvents, metals and dust) as a carcinogen.
The organization’s International Agency for Research on Cancer determined that an increased exposure to outdoor air pollution and particulate matter causes lung cancer and increases the risk of developing bladder cancer.
Particulate matter consists of extremely small solid particles and liquid droplets found in the air. The risk of lung cancer associated with air pollution is less in the U.S. than in countries with poor air quality, such as India and China, but should still be taken seriously, especially in highly industrialized cities. In 2010, the Global Burden of Disease Project estimated 223,000 worldwide deaths from lung cancer associated with air pollution.
Silica is a naturally occurring mineral found in sand, rocks and mineral ores. Its most common form is quartz. The mineral is a component in many building materials, including bricks, concrete and granite. When workers drill or cut into these products and inhale the fine silica dust created, it can lead to a lung disease known as silicosis. Much like asbestos, exposure to silica generally happens in occupational settings such as mining, glass manufacturing and foundry work. Inhaling silica particles and dust causes scarring of the lungs over time. Silicosis increases the risk of lung cancer, as well as conditions such as tuberculosis and chronic bronchitis.
Along with other tangible causes of lung disease, genetics also play a key role in the development of the condition, as is the case with most cancers.
While parents sometimes pass on DNA mutations to their children that greatly increase their risk for developing certain cancers, such as breast cancer, most lung cancers are not caused by inherited genes alone.
Still, people who inherit gene changes in chromosome 6 — one of the 23 pairs of chromosomes in the humans — are more likely to develop lung cancer, even if they don’t smoke a lot or at all.
Genetics can also make you more susceptible to develop lung cancer from asbestos, radon or secondhand smoke exposure. Gene mutations that result from exposure to these environmental factors are called acquired gene changes.
Be Aware of Other Factors and Seek Help
The dangers of smoking cigarettes and other tobacco products are well known. While smoking drastically increases your chances of developing lung cancer, it is not the sole cause.
Even if you’ve never smoked in your life, you could be at risk. If you have a history of exposure to asbestos, radon or other toxic air pollutants, you should seek medical help immediately.
And remember, a genetic history with lung cancer and other cancers puts you at a greater risk.
Smoking is not a prerequisite for lung cancer.