Michael Hunter, MD on Medika Life

The Second Leading Cause of Lung Cancer Will Surprise You

YOU KNOW ABOUT CIGARETTE SMOKING AND LUNG CANCER. But what would you guess is the world’s second most common cause of lung cancer? Did you guess asbestos? Radon? Inherited genetics?

If you guessed air pollution, you are spot on. After smoking, air pollution is the second leading cause of lung cancer worldwide. That’s the finding of a new analysis.

Today we look at new data showing variability in lung cancer incidence by geography. You’ll learn which countries are the most affected, how coal affects risk, and how those of us who care about those with cancer can use our voices to fight back.

Photo by Malcolm Lightbody on Unsplash

“So, whether the aliens explore with chemistry or with radio waves, they might come to the same conclusion: a planet where there’s advanced technology must be populated with intelligent life-forms, who may occupy themselves discovering how the universe works and how to apply its laws for personal or public gain.

Looking more closely at Earth’s atmospheric fingerprints, human biomarkers will also include sulfuric, carbonic, nitric acids, and other components of smog from burning fossil fuels. Suppose the curious aliens are socially, culturally, and technologically more advanced than we are. In that case, they will surely interpret these biomarkers as convincing evidence for the absence of intelligent life on Earth.”
― Neil deGrasse Tyson, Astrophysics for People in a Hurry

Lung cancer problem scope

Lung cancer is the third most common cancer in the United States. The Centers for Disease Control and Prevention explains that skin cancer is the most common cancer type in the USA, followed by prostate cancer (among men) and breast cancer (among women).

Lung cancer is the leading cause of death due to cancer in the United States among men and women.

Across the globe, lung cancer is the second most common cancer. By sex, it is the leading cancer in men and the second most common cancer in women.

There are more than 2.2 million new lung cancer cases each year. Here are the countries with the highest incidences of lung cancer, according to the World Cancer Research Fund International (cases per 100,000):

  1. Hungary 50
  2. Serbia 47
  3. France, New Caledonia 43
  4. French Polynesia 41
  5. Turkey 40
  6. Montenegro 40
  7. Belgium 38
  8. Bosnia and Herzogovenia 38
  9. North Korea 37
  10. Denmark 37

The death rates are highest in Hungary, Serbia, French Polynesia, Turkey, and Guam.

Photo by Ray Reyes on Unsplash

Lung cancer causes

Smoking is the main cause of the two main forms of lung cancer: small and non-small cell. Cigarettes contribute to 80 percent of lung cancer deaths in women, and 90 percent of men, respectively.

Men who smoke are 23 times more likely to get lung cancer than non-smokers. Women are 13 times more likely, compared with never smokers.

Smoking can affect those of us who are non-smokers. In the United States, exposure to secondhand smoke is related to about 7,330 lung cancer deaths among non-smokers yearly. Non-smokers have a 1.2 to 1.3-fold risk of developing lung cancer if exposed to secondhand smoke at home or work.

Other lung cancer causes

Besides smoking and the factors detailed above, other proven causes of lung cancer include:

  • Previous lung disease (such as tuberculosis, pneumonia, emphysema, or chronic bronchitis).
  • Having antibodies to Chlamydia pneumoniae, bacteria that can cause chest infections.
  • Exposure (such as at work) to asbestos, radon, crystalline silica, mixtures of polycyclic aromatic hydrocarbons, and heavy metals are linked with an increased risk of lung cancer. Radon exposure is second only to smoking as a causative agent of lung cancer.
  • Indoor air pollution (for example, from wood and coal burning for heating and cooking.

If you drink water containing arsenic, your lung cancer risk rises. Among current and former smokers, taking high doses of beta-carotene supplements increases lung cancer risk.

On the other hand, the World Cancer Research Fund International offers some potential risk-reducing strategies:

  • Limit red meat, processed meat, and alcoholic drinks, as these substances may increase the risk of lung cancer.
  • Increasing your fruit and vegetable intake for current and former smokers may lower your lung cancer risk.
  • Foods [not supplements] with beta-carotene, carotenoids, or retinol may drop your lung cancer risk.
  • In current users of cigarettes, vitamin C-containing food may lower the risk.
  • For never-smokers, foods with isoflavones may drop the risk.
  • Physical activity may decrease the risk of lung cancer.

Air pollution and lung cancer

Could pollution be the second leading cause of lung cancer? A novel study suggests that 14.1 percent of lung cancer deaths worldwide are directly linked to air pollution.

This new finding puts air pollution as the second leading cause of lung cancer, exceeded only by smoking.

The researchers report that the lung cancer death burden attributable to air pollution is lower in the USA, where 4.7 percent of deaths due to the disease are directly linked to pollution.

Unfortunately, we in the western USA have seen a recent increase in wildfires and can expect to pay the price for our exposure to this unpleasant air. The study authors also found an association between deaths from lung cancer worldwide and the proportion of national energy produced by coal.


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Michael Hunter, MD
Michael Hunter, MD
I received an undergraduate degree from Harvard, a medical degree from Yale, and trained in radiation oncology at the University of Pennsylvania. I practice radiation oncology in the Seattle area.

Michael Hunter, MD

I received an undergraduate degree from Harvard, a medical degree from Yale, and trained in radiation oncology at the University of Pennsylvania. I practice radiation oncology in the Seattle area.

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