World Lung Cancer Day 2023: Can Passive Smoking Cause Cancer? See What Experts Say

Lung cancer is more common in smokers, and more than 80% of lung cancer patients smoke often. Other risk factors include secondhand smoke, radon, air pollution, and a family history of lung cancer.

New Delhi: World Lung Cancer Day is observed on Augusr 1, since 2012, to raise awareness of the terrible disease, stimulate more research, and break the stigma associated with it. Lung cancer is more common in smokers, and more than 80% of lung cancer patients smoke often. Other risk factors include secondhand smoke, radon, air pollution, and a family history of lung cancer. People should be on the lookout for indicators of lung cancer such as a persistent cough, trouble breathing, coughing up blood, chest pain, and exhaustion and get the necessary tests done after consulting a specialist.

In this regard, Dr. Col Dutta who is a Sr. Consultant - Internal Medicine & Pulmonology, Indian Spinal Injuries Centre, New Delhi said, "The biggest cause of cancer-related death worldwide is lung cancer and there is an alarming increase in lung cancer cases in India. Although smoking continues to be the main cause of lung cancer, the dangers that pollution and passive smoking pose to non-smokers cannot be ignored. Air pollution, occupational exposure, and/or the potential involvement of infectious microorganisms are the major causes. Smoking needs to be addressed together with other environmental toxins such arsenic, chromium, nickel, asbestos, and dioxins."

What Is Passive Smoking?

Dr. Vandana D Prabhu who is a pulmonologist at Apollo Clinic, HSR Layout explained what passive smoking is and said, "Environmental tobacco smoke is a common source of indoor air pollution worldwide, and its inhalation is known as passive smoking. Passive smoking means breathing in other people’s tobacco smoke. If you live with someone who smokes, you have a higher risk of diseases such as lung cancer, heart disease and stroke."

Additionally, passive smoking is classified as a Group 1 carcinogen, meaning it is proven to cause cancer in humans. Exposure to second hand smoke can lead to lung cancer in nonsmokers, says Dr. Pavan Yadav, Lead Consultant - Interventional Pulmonology & Lung Transplantation, Aster RV Hospital.

Approximately 16% of lung cancer cases among non-smokers are potentially attributable to passive smoking, she further went on to say. 

"This is slightly higher among women (around 18%), with most cases occurring due to household exposure. The biological plausibility for this association is that carcinogens and toxic substances seem to remain present in side-stream smoke and exhaled mainstream smoke. Exposure to passive smoking is a major public health concern, resulting in a large economic burden worldwide," she further added.

Effects Of Passive Smoking On Health

Dr Aman Priya Khanna, who is a Laser, Bariatric, and Minimal Access Surgeon and Co-founder & medical director of HexaHealth shared the effects of passive smoking on health.

He said, "Tobacco smoke has more than 5000 chemicals, the majority of which are harmful. They quickly spread through the air, linger for hours and accumulate on surfaces and clothing."

• Exposure to passive smoking elevates the risk of lung cancer, heart disease, stroke and Chronic Obstructive Pulmonary Disease (COPD).


• Nonsmokers exposed to secondhand smoke account for about 7,330 lung cancer deaths annually.


• Short-term effects are coughing, headaches, sore throats, and irritation of the eyes and nasal passages.


• Pregnant women have significant risks to the baby during and after birth, increasing the chances of low birth weight and cot death.


• Even children are at greater risk of asthma attacks, impaired lung function, ear infections and other health issues.

How Passive Smoking Leads To Lung Cancer?

Cigarette smoke contains over 70 known carcinogenic chemicals. Nonsmokers inadvertently inhale the same toxins. It can compromise the immune system's defences against cancer cells and other diseases, rendering them more vulnerable. People working close to smokers face serious occupational hazards, especially in enclosed spaces.

In this regard, Dr Aman said, "The smoke exhaled by the smoker directly is called mainstream smoke. When a smoker takes a drag on a cigarette, pipe, or cigar, a non-smoker inhales this mainstream smoke, which contains the same harmful chemicals as in the tobacco product."

"Sidestream smoke comes from the burning end of a cigarette, pipe, or cigar. It is more dangerous because it is produced at a lower temperature and, as a result, contains higher concentrations of harmful substances, including carcinogens (cancer-causing agents), more so as it does not pass through the filter end of tobacco products," he further added.

How To Prevent Passive Smoking And Reduce The Risk Of Lung Cancer?

Harmful particulate matter and toxic gases due to increased city air pollution combined with secondhand smoke compound the problem, which can exacerbate stated issues. The toxins of tobacco smoke stay suspended for a very long time in already polluted air. It adds more irritants, thus creating a more pronounced and prolonged response in the airways. 

In this regard, Dr Aman listed out some ways to prevent passive smoking:

• Creating a smoke-free environment is crucial in discouring smoking. Most exposure occurs within homes where smoke can easily travel between rooms and linger in the air, even with open windows. Encourage smokers to smoke outside to minimise indoor exposure. 


• Request visitors to smoke outdoors and refrain from smoking or allowing others to smoke inside the car, as secondhand smoke can accumulate to high levels in the enclosed space, even with open windows.


• Advocate and support smoke-free policies in public places, workplaces, and homes to promote healthier environments. Choose smoke-free establishments like restaurants, bars, and public spaces to avoid exposure when possible. 


• Educate friends, family, and colleagues about the hazards of secondhand smoke and its association with lung cancer, empowering them to make informed choices about smoking habits.


• Encourage and support smokers to quit smoking. Smoking cessation benefits their health and reduces the risk of exposing others to secondhand smoke.


• Protect children, as they are the most vulnerable victims. Never smoke in the presence of children, and ensure that they are not exposed to smoke in any environment.

"The combined effect of passive smoking and air pollution can intensify oxidative stress (due to free radicals) in the body, making it harder for the body to repair and recover from damage. It also increases the frequency and severity of exacerbations leading to decreased respiratory capacity and vulnerability to infections," he concluded.

How To Detect Lung Cancer?

Lung cancer is a dangerous foe that needs cautious assessment through a medical history and physical examinations. Dr. Vinay Bhatia, Head- Molecular Biology National Reference Lab and Oncquest Laboratories Limited, Gurugram, listed out the tests that can help one detect lung cancer.

• Chest X-rays, CT scans, PET scans or MRI are imaging procedures, being used to reveal its elusive existence, exposing questionable spots and revealing the degree of its spread.


• With their radioactive sugar injections, PET scans to reveal malignant lesions which may have been overlooked or difficult to characterize by conventional CT scan, X-ray, or MRI.


• Lung biopsies are examined under a microscope by a pathologist to provide definitive diagnosis.


• Molecular mutations testing is a crucial prognostic tool. These mutations, which range from KRAS and EGFR to ALK and RET, provide valuable information about tumor's biology, guide treatment decisions and predict response to targeted therapies.


• Additionally, PDL 1 testing in a patient’s tumor tissue can determine whether a patient might benefit from immunotherapy medications.


• Liquid biopsies based on non-invasive testing analyse tumor related biomarkers such as circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs), which has shown promising potential tool for cancer monitoring and treatment decisions-making.

Tips To Improve Lung Health:

Dr. Col Dutta said, "To improve lung health, embrace a healthy lifestyle. Avoid smoking and exposure to pollutants, exercise regularly, and adopt a balanced diet with plenty of fruits and vegetables. Incorporate food such as oranges, lemons, broccoli, carrots, almonds, walnuts, flaxseeds, turmeric and include green tea for a better lung health. Regular health check-ups and screenings should be done."