According to the American Cancer Society, lung cancer is the second most common cancer among both women and men in the United States. However, because lung cancer is often only caught at a later stage, it is by far the leading cause of cancer death.

There are several factors that can increase your risk of developing lung cancer. These can be divided into three categories:

  • lifestyle risk factors
  • personal risk factors
  • environmental risk factors

In this article, we’ll address each of these three categories in more detail, and discuss lung cancer screening protocols and who should get screened.

Lifestyle risk factors are those factors that you can actively change and have some level of control over. They include things like smoking and your diet.

Here’s what we know about the different lifestyle risk factors for lung cancer.


Smoking is the top risk factor for lung cancer. In fact, the American Cancer Society estimates that smoking is linked to about 80 percent of lung cancer deaths.

This risk factor isn’t just limited to cigarette smoking, though. Smoking other tobacco products, such as cigars or pipes, also increases your risk. Additionally, using low-nicotine or low-tar products doesn’t reduce your risk of lung cancer.

According to the Centers for Disease Control and Prevention (CDC), tobacco smoke contains over 7,000 different chemicals, at least 70 of which are known to cause cancer. Inhaling these chemicals can cause harmful changes inside your lungs that can increase your risk of cancer.

People who smoke tobacco products have about 20 times the risk of lung cancer compared to people who don’t smoke. Additionally, the longer and more frequently you smoke, the higher your risk.

Quitting smoking can reduce your risk of lung cancer. However, people who’ve quit smoking still have a higher risk of developing lung cancer than people who’ve never smoked.

Secondhand smoke exposure

Even if you don’t smoke, frequent exposure to tobacco smoke can also increase your risk of lung cancer. This can happen if you live or work with people who smoke tobacco products.

According to the CDC, lung cancer risk increases by 20 to 30 percent among nonsmokers who are often around secondhand smoke. In fact, secondhand smoke causes over 7,300 deaths among nonsmokers every year in the United States.

When you inhale secondhand smoke, the effect is similar to smoking. This is because you’re still bringing the harmful chemicals in tobacco smoke into your lungs, albeit in smaller amounts.

As with smoking, lung cancer risk increases based on how often and how long you’re around secondhand smoke. You can reduce your risk by taking steps to limit your exposure to secondhand smoke.


Certain dietary factors may also increase lung cancer risk. For example, research has found that smokers who take beta carotene supplements are at an increased risk of lung cancer.

Also, some research indicates that a high intake of alcohol or red meat may increase lung cancer risk. However, additional studies are needed.

In some parts of the world, drinking water can contain high levels of the harmful chemical arsenic, which has been linked to increased lung cancer risk. However, drinking water in the United States isn’t a major source of arsenic.

Personal risk factors for lung cancer are those things that you typically can’t change, like your age, family medical history, and previous health conditions.

Let’s take a look at these risk factors in more detail.

Family or personal history of lung cancer

Some cancers can run in families. Because of this, your risk of lung cancer may be higher if an immediate family member had lung cancer, particularly if they were diagnosed at a young age.

Immediate family members include your:

  • parents
  • siblings
  • children

According to the National Cancer Institute, having a relative with lung cancer may double your risk of the disease. However, keep in mind that having a family history of lung cancer doesn’t necessarily mean that you’ll develop it as well.

Researchers are still trying to understand how lung cancer risk is linked to genetics. This effort is complicated by the fact that many lifestyle and environmental risk factors, such as smoking and radon exposure, may be shared among family members.

Additionally, people who’ve been diagnosed with lung cancer are at an increased risk of having another type of lung cancer. This is particularly true if you smoke.


Advancing age is a risk factor for lung cancer. In fact, most people who develop lung cancer are older individuals. According to the American Cancer Society, the average age of someone newly diagnosed with lung cancer is 70.

Age likely increases your risk due to the effects of other factors, such as lifestyle habits and environmental factors. The older you are, the longer you’re likely to have been exposed to things like tobacco smoke and air pollution.

Previous radiation exposure

People who’ve been exposed to radiation in their chest area are also at an increased risk of lung cancer. A couple of ways this can happen include:

As with other risk factors, your risk of lung cancer increases if you smoke in addition to having had previous exposure to radiation.

Other medical conditions

Some types of lung conditions, such as chronic obstructive pulmonary disorder (COPD) and tuberculosis, can increase your risk of lung cancer.

It’s possible that inflammation may drive the changes that can lead to cancer with these diseases. However, the exact mechanism of how these lung conditions increase lung cancer risk is currently unknown.

Additionally, living with human immunodeficiency virus (HIV) is associated with increased lung cancer risk. This may be due to a combination of the virus’s effect on the immune system and high rates of smoking among people living with HIV.

Environmental risk factors are those things that you may not always have complete control over. However, you can certainly try to take steps to limit your exposure to them.

Here’s what we know about the environmental risk factors for lung cancer.

Radon exposure

Radon is a type of radioactive gas that occurs naturally in rocks and dirt. It’s both colorless and odorless. Because radon is radioactive, breathing in air that contains radon exposes your lungs to small levels of radiation.

According to the Environmental Protection Agency (EPA), radon is the second leading cause of lung cancer in the United States. It’s estimated to cause about 21,000 lung cancer deaths each year.

Although radon is present outdoors, it disperses easily and is unlikely to be harmful. The real danger comes when radon seeps through cracks or holes in the foundation of houses and buildings and accumulates indoors. This increases the concentration of the gas and exposes you to higher levels.

In fact, it’s estimated that 1 in 15 homes in the United States has high radon levels. You can have your home inspected to check for and address high radon levels.

Exposure to other hazardous substances

There are several other hazardous substances that can increase your risk of lung cancer, including:

Exposure to these substances typically occurs in a work environment, often in industrial or mining jobs.

Your lung cancer risk increases if you smoke and are frequently exposed to any of these known hazardous substances.

Air pollution

Exposure to air pollution may slightly raise the risk of lung cancer. This can include both outdoor and indoor air pollution.

High levels of outdoor air pollution can occur in large cities or areas that have heavy traffic. The American Cancer Society estimates that about 5 percent of lung cancer deaths worldwide are due to outdoor air pollution.

A potential source of indoor air pollution is long-term exposure to fumes from coal, wood burning, or certain unrefined cooking oils. This is more likely to occur in poorly ventilated buildings.

Lung cancer screening can help detect lung cancer before symptoms begin. When cancer is detected early, treatment is often more effective.

The screening test for lung cancer is a type of CT scan called a low-dose CT scan. This test uses a low amount of radiation to produce images of your lungs. Your healthcare provider can then review these images for signs of cancer.

Lung cancer screening guidelines

The United States Preventative Services Task Force recommends yearly lung cancer screenings for people who meet all three of the criteria outlined below.

  1. You are between the ages of 50 and 80 years old.
  2. You have a history of heavy smoking, which is defined as 20 pack-years or more (i.e., smoking one pack a day for 20 years).
  3. You currently smoke or have quit smoking within the past 15 years.

The screening guidelines recommended by the American Cancer Society are generally similar to those listed above. However, in this case, the age range is different: 55 to 74 years of age.

If you’re thinking about being screened for lung cancer, speak to your healthcare provider. They can help determine if you’re a good candidate for screening and direct you to a nearby screening facility.

There are many different risk factors for lung cancer. Some you can change, while others are outside of your control.

The most important step you can take to help prevent lung cancer is to quit smoking. Staying away from secondhand smoke and avoiding exposure to radon and other harmful chemicals may also help lower your risk.

Screening for lung cancer is a valuable tool that can help detect lung cancer at an early stage, when it’s easier to treat. If you’re interested in being screened for lung cancer, talk to your healthcare provider.