What Are The Risk Factors For Lung Cancer? Smoking & Lung Cancer

Lung cancer risk factors

Most people would say that tobacco consumption is the cause of lung cancer, and that is partly true. But only reducing lung cancer risk factors to tobacco smoking would be oversimplifying. There are many others to consider.

In this article, we’re going through the risk factors that increase the likelihood of lung cancer. Some of them can be changed by making adjustments to your lifestyle. Others cannot be altered in any way. And still, others are under active research, and we are still not sure if they increase the risk or not.

Modifiable Risk Factors

Modifiable risk factors

Modifiable risk factors are those that we can change by doing something different or changing something in our lives.

Modifiable risk factors for lung cancer include:

  • Tobacco smoking: It is probably the most important modifiable risk factor. 80% of people who die from lung cancer were smokers, and most of them, heavy smokers. Small cell lung cancer is one of the most aggressive types of cancer, and most cases are related to smoking. It is very rare to find one of these cancers in people who have never smoked. The burden of this risk factor is proportional to how frequently you smoke, and the more packs of cigarettes you smoke every day, the greater the risk. Almost all smoking types are directly associated with cancer, including pipe smoking, cigarette smoking, and other variants. Even menthol cigarettes and low-tar cigars have the same effect in increasing the risk of lung cancer.
  • Passive smoking: It is also known as secondhand smoke or environmental tobacco smoke because you’re not the one holding the cigarette, but you’re still breathing the smoke that comes out of other people. Thus, the risk of lung cancer in these cases is significantly higher. Secondhand smoking is also a cause of death by lung cancer, and around 7,000 deaths a year are estimated for this risk factor. Passive smoking is a risk factor in families or households where one individual smokes heavily, and the rest become affected by remaining close to him.
  • Radon exposure: Radon is a radioactive gas found in nature. It results from uranium decay, and it is impossible to perceive by smell or taste. In the United States, radon exposure is the second cause of lung cancer and the number one cause among nonsmokers. The most dangerous type of radon exposure is found indoors because the airflow typically takes out outdoor exposure. Indoors, radon becomes concentrated, and people breathe this substance without realizing it. Basements can be a source of radon, and it is possible to measure its levels to make sure that we’re not exposed to this substance.
  • Asbestos exposure: For many years, asbestos exposure was a concerning problem in houses and buildings. Many houses were made with products that contained asbestos, but current regulations do not allow this. Still, it is used in textile plants, mines, mills, and other occupational sources. Workers exposed to asbestos are more likely than the general population to suffer from lung cancer of a particular type called mesothelioma.
  • Other carcinogens exposure: Other carcinogens in the workplace include uranium in radioactive ores, Diesel exhaust, and chemicals such as arsenic, coal products, nickel, silica, cadmium, mustard gas, among others. Industry workers in contact with these and other carcinogens have a higher risk of lung cancer and different cancer types.
  • Incorrect supplement use: Not all supplements are beneficial for lung cancer, and vitamin A is a clear example. One would think that the antioxidant properties of beta carotene make it a useful supplement against cancer. But smoking heavily and consuming high beta carotene levels is a bad combination and increases the risk of lung cancer.

Non-Modifiable Risk Factors

Non-modifiable risk factors

This type of risk factor cannot change by a change of habits or a revision of our house and the workplace.

Non-modifiable risk factors for lung cancer include:

  • A history of radiotherapy: If you had previous radiation therapy in areas of the chest, the risk of lung cancer increases. The risk is even higher in smokers and people with overlapping risk factors. Radiotherapy in the chest is common in Hodgkin disease, breast cancer, and other types of cancer that involve the chest area.
  • Air pollution: This is a common risk factor in populated cities because smog and air pollution work similarly to passive smoking but to a lesser degree. Still, it is a prevalent source of cancer in the population as a whole, and it is thought that 5% of cancer cases worldwide are caused by air pollution.
  • Medical history of lung cancer: A previous history of lung cancer increases your risk of recurrence. Another tumor may appear in the same lung or the opposite lung in patients who recovered from the disease. Additionally, the history of lung cancer may not come from yourself. If one of your close relatives had lung cancer, your chances are higher than the average, especially if they developed the disease at a young age. This is probably due to a genetic predisposition to lung cancer, but other aspects also play a role, such as environmental exposure to radon and tobacco smoke.

Risk Factors Under Research

Risk factors under research

Other risk factors are under active research because we still don’t know if they have a significant role in developing lung cancer.

They include:

  • Marijuana smoking: Similar to tobacco smoking, marijuana contains tar and other carcinogenic substance found in tobacco. Unlike tobacco smoking, people who smoke marijuana do it all the way to the end of the joint, so they are more likely to smoke the part where tar is more highly concentrated. Moreover, marijuana is inhaled profoundly, and smokers usually keep the smoke inside for extended periods, increasing the lungs’ exposure and the chance of carcinogens deposits in the lung structures.
  • Electronic cigarettes: Electronic cigars use an electronic nicotine delivery, and even if they don’t have tobacco, they still don’t have enough research to say if they are harmless or not.


Malhotra, J., Malvezzi, M., Negri, E., La Vecchia, C., & Boffetta, P. (2016). Risk factors for lung cancer worldwide. European Respiratory Journal48(3), 889-902.

Akhtar, N., & Bansal, J. G. (2017). Risk factors of Lung Cancer in nonsmoker. Current problems in cancer41(5), 328-339.