Health and Fitness

Why do non-smokers get lung cancer?

Tobacco is a poison. But, how does a non-smoker succumb to it?

While smoking happens to be an undisputed cause of cancer, lung cancer isn’t restricted to only chronic smokers. Former smokers and even non-smokers are known to develop this type of carcinoma.

Lung cancer is the most common type of cancer across the globe. In 2012 alone, 1.8 million new cases were diagnosed globally. The disease is a widespread health concern and to make the matters worse, patient survival has barely improved over the last few decades.

In the 1970s, the chance of surviving 10 years after diagnosis was 3%; in 2010-11, it increased to a marginal 5%. While in the same time period, the post-diagnosis survival of a patient suffering from breast cancer nearly doubled to 78.5% from 40%.

As a matter of fact, each year, out of approximately 200,000 Americans who develop lung cancer, nearly 20,000 cases are of non-smokers. While every smoker has a high lung cancer risk, the risk is shared by those who haven’t ever had a puff in their lives. What’s more, a number of conditions and circumstances are known to increase a non-smoker’s risk of developing lung cancer.

A common view is that lung cancer is self-inflicted and the problem will disappear when everyone gives up the habit. This isn’t the case.

Passive smoking

 Passive smoking refers to inhalation of tobacco smoke from others in the vicinity, be it in the workplace or at home. It is a well-known risk factor for lung cancer. Statistically speaking, non-smokers who share their living quarter with smokers increase their own risk of developing lung cancer by a whopping 24%. In the US, each year, nearly 3,000 deaths related to lung cancer are attributed to lung cancer.

This, however, should not be used as grounds for discrimination. As they always say, precaution is better than cure. While passive smoking is an established risk factor, some consideration and awareness should never go amiss.

While 85% of lung cancer cases are caused by cigarette smoking, it is imperative to understand the turn of cogs behind non-smoking related lung cancer. Also, women are speculated to be more susceptible to non-smoking-related lung cancer, as about 67% of non-smoker lung cancer patients were women.

Inhaling Radon gas

Radon is a naturally-occurring gas that is released when a radioactive element named uranium decays. This gas can easily escape from underground radioactive waste dumps. It will, then, traverse to the surface of the soil and enter homes through drains, pipes and other openings. As this gas is both colourless and odourless, detection is possible only with specialized test kits. More worrying yet, the U.S. Environmental Protection Agency speculates that of every 15 homes in the U.S., at least one contains very high levels of Radon gas – a dangerous development, to say the least.

It makes complete sense that a gas which is associated with radioactive compounds causes cancer. But what does not make sense is how it is considered to be the cause of nearly 12% of all lung cancer deaths in the U.S. It is estimated that 15,000 – 20,000 deaths, in both smokers and non-smokers, occur due to radon gas exposure. Those who smoke are at a significantly higher risk than non-smokers when exposed to the gas.


This public health menace was once marketed as ‘magic mineral’. Asbestos occurs naturally and can be pulled into a fluffy consistency. And, though it is soft and flexible, it is highly resistant to heat, chemical corrosion and electricity. An effective insulator, pure asbestos can be mixed into cloth, paper, plastic and cement etc. to add a considerable strength to them.

While qualities had made asbestos business quite profitable, they also made it highly toxic.

When microscopic fibres of asbestos break loose from the insulation material, they are released into the air. Naturally, they can be inhaled. But, the havoc they wreak over time is far greater than the benefit it does. These fibres stick around for a long time in the lungs and are associated with lung cancer. People who work around asbestos, who do not even smoke, have a 5-times higher risk of developing lung cancer when compared to other non-smokers.

Smoking, when paired with asbestos inhalation, can drastically increase the odds of developing lung cancer related to asbestos.

Keeping public health in mind, the use of asbestos is limited and even banned in many countries.


Cancer has been widely known to be genetic as well. Hence, it isn’t only the environment but also the genes of a person that lead to the development of cancer, lung or others. Nearly 5-10% of cancers are caused due to genetic reasons. Individual genetic susceptibility has a role to play in the development of cancer. Also, studies have shown that people (both smokers and non-smokers) with relatives who have had lung cancer have a higher susceptibility to lung cancer than the general population.

Air Pollution

What we term as ‘air pollution’ is the mixture of harmful substances found in the air we breathe. The contents and their concentration may vary upon the source, the time of the year, the weather and, of course, your location. The contents can be natural substances, like desert dust, or artificial ones like burning fuels and car fumes.

Air pollution can increase the risk of lung cancer. Approximately 2,000 lung cancer deaths in the U.S. can be attributed to air pollution and experts believe that prolonged exposure can have effects similar to that of passive smoking.

The saddest part isn’t that the occurrence of lung cancer has increased or the survival rate hasn’t improved much; it is that lung cancer isn’t getting the research funding it deserves. For example, Canada, which has the second highest rate of lung cancer in the world and 25% cancer deaths attributable to it, ploughs in only 7% of research funding into lung cancer. Hopefully, the world shall see the day when the rate of lung cancer survival won’t be this far and few between.