Research has found several risk factors for lung cancer. A risk factor is anything that changes the chance of getting a disease. Different risk factors change risk by different amounts.

The risk factors for lung cancer include-

  • Smoking and being around others' smoke.
  • Things around us at home or work, such as radon gas.
  • Personal traits, such as having a family history of lung cancer.

Smoking and Secondhand Smoke

Cigarette smoking causes lung cancer. In fact, smoking tobacco is the major risk factor for lung cancer. In the United States, about 90% of lung cancer deaths in men and almost 80% of lung cancer deaths in women are due to smoking. People who smoke are 10 to 20 times more likely to get lung cancer or die from lung cancer than people who do not smoke. The longer a person smokes and the more cigarettes smoked each day, the more risk goes up.

People who quit smoking have a lower risk of lung cancer than if they had continued to smoke, but their risk is higher than the risk for people who never smoked. As more people quit smoking, lung cancer rates will continue to fall, the percentage of lung cancers that occur in smokers will decrease, and the percentage of lung cancers that occur in people who have quit will rise.

Smoking also causes cancer of the voicebox (larynx), mouth and throat, esophagus, bladder,kidney, pancreas, cervix, and stomach, and causes acute myeloid leukemia.

Using cigars or pipes also increases risk for lung cancer, but not as much as smoking cigarettes.

Smoke from other people's cigarettes (secondhand smoke) causes lung cancer as well. Secondhand smoke contains more than 4,000 chemicals, more than 50 of which cause cancer in people or animals. Every year, about 3,000 nonsmokers die from lung cancer due to secondhand smoke.

Things at Home and Work That May Cause Lung Cancer

Several things may cause lung cancer in the workplace or even in the home-

  • Radon gas causes lung cancer and is sometimes found in people's homes. Radon is an odorless, colorless gas that comes from rocks and dirt and can get trapped in houses and buildings. Radon is the number one cause of lung cancer among non-smokers, according to EPA estimates.External Overall, radon is the second leading cause of lung cancer.
  • Examples of substances found at some workplaces that increase risk include asbestos,arsenic, and some forms of silica and chromium. For many of these substances, the risk of getting lung cancer is even higher for those who also smoke. 
  • Other substances may increase lung cancer risk as well.

Family History

Risk of lung cancer may be higher if a person's parents, siblings (brothers or sisters), or children have had lung cancer. This increased risk could come from one or more things. They may share behaviors, like smoking. They may live in the same place where there are carcinogens such as radon. They may have inherited increased risk in their genes.


Scientists are studying many different foods to see how they may change the risk of getting lung cancer. However, any effect diet may have on lung cancer risk is small compared with the risk from smoking. Eating a lot of fat and cholesterol might increase risk of lung cancer. Drinking a lot of alcohol may raise risk as well. However, it's hard to tell how much of the risk in people who drink is actually due to tobacco smoke, since many people both smoke and drink.

Some foods may actually help prevent lung cancer. Diets high in fruits and vegetables likely decrease cancer risk. Diets high in vitamin C, vitamin E, or selenium also may help protect against lung cancer. The effect of eating foods with carotenoids like beta-carotene on lung cancer risk is uncertain. Carotenoids can be found in carrots, sweet potatoes, and some green vegetables. Eating these foods may lower chances of lung cancer. Taking beta-carotene supplements (pills) is not recommended, however, since it may actually increase risk in some smokers.