Lung cancer in non-smokers: Doctors point out passive smoking and air pollution as main causes

Last month, the TV presenter and newscaster Aparna Vasthray dies of lung cancer Her death has raised concerns in Bengaluru about risk factors for lung cancer that are now affecting even non-smokers.

This is an alarming trend, said doctors, who blame passive smoking and air pollution for the rise in lung cancer among non-smokers.A recent study by the Indian Council of Medical Research-National Centre for Disease Informatics and Research (ICMR-NCDIR), Bangalore, looked at various published studies and found a strong association between air pollution and cancer, with airborne fine particulate matter (PM2.5) and nitrogen dioxide (NO2) in particular being associated with increased lung cancer and associated mortality.

Microscopic pollutants penetrate deep into the lungs, causing inflammation and damaging lung tissue. Chronic exposure to these pollutants can lead to mutations in lung cells and ultimately cancer. The risk is significant even for non-smokers who breathe polluted air every day, the doctors said.

Apart from genetic factors, several occupations in India expose workers to substances that cause lung cancer. Workers in mining, construction and certain manufacturing industries are at higher risk.

Passive smoking

Vinayak Maka, head of medical oncology at Ramaiah Memorial Hospital, said lung cancer among non-smokers is an alarming trend. “Passive smoking remains a major risk factor and many non-smokers inhale the smoke around them, increasing their risk of developing lung cancer,” he said.

“Apart from air pollution, occupational exposure to carcinogens such as asbestos, radon and certain chemicals further increase the risk among non-smokers. Genetic predisposition is also an important factor. Some people may be susceptible to lung cancer due to genetic mutations despite never having smoked. In addition, lifestyle factors such as diet and physical activity, as well as underlying conditions such as chronic lung disease, can also affect cancer risk,” he pointed out.

Niti Raizada, senior director, medical oncology and haematology-oncology, Fortis Hospital, Bengaluru, said the health effects of smoke are far more far-reaching than the act of smoking itself.

“It is widely known that lighting a cigarette is dangerous, but many people are unaware of the dangerous hazards that linger in the smoke that lingers long after the cigarette has been extinguished. Understanding the risks associated with direct, passive and even thirdhand smoke is essential to understanding the full extent of the lung cancer threat and protecting our health from this deadly disease,” she said.

smoking

Passive smoking, or active smoking, is inhaling smoke directly from a cigarette, cigar or pipe. This type of smoke contains thousands of harmful chemicals, many of which are known carcinogens. The risks associated with passive smoking – direct lung damage and significant cancer risk – are well documented. Beyond cancer, smoking is a leading cause of chronic obstructive pulmonary disease (COPD), heart disease and stroke, affecting overall health and quality of life, she said.

Dr Raizada said there was a hidden danger in secondhand or passive smoke, saying: “Smoke that non-smokers inhale from the end of a lit cigarette or a smoker's exhaled breath poses serious health risks even without direct contact.”

Children and pregnant women are especially at risk. In children, secondhand smoke can cause respiratory infections, asthma and developmental problems. Pregnant women exposed to secondhand smoke are at higher risk of low birth weight and premature birth. Additionally, because secondhand smoke floats in the air and settles on surfaces, it can pose an ongoing health risk in enclosed spaces, she explained.

Passive smoking

Third-hand smoke refers to residues of nicotine and other toxic chemicals that remain on indoor surfaces long after a person has stopped smoking. “Third-hand smoke residue can get on walls, furniture and clothing. Children and pets who come into contact with contaminated surfaces can ingest or inhale the harmful substances, putting them at increased risk of health problems,” the doctor said.

“Furthermore, thirdhand smoke residues can interact with other indoor pollutants to produce even more harmful compounds, which can exacerbate health risks, especially in environments where smoking is a common occurrence. Even if you have never smoked or been exposed to secondhand smoke, living in an environment with thirdhand smoke pollution can pose health risks, especially over the long term,” she explained.

Symptoms and precautions

Symptoms of lung cancer include a cough (often bloody), chest pain, wheezing, and weight loss. These symptoms often do not appear until the cancer is advanced. Treatment options vary but may include surgery, chemotherapy, radiation therapy, targeted drug therapy, and immunotherapy.

Doctors say the most effective way to reduce the risk of lung cancer is to avoid smoking and limit exposure to secondhand smoke. Additionally, maintaining a smoke-free environment and reducing exposure to residual smoke are also essential preventative measures.

A multifaceted approach is now required to effectively tackle lung cancer. The general public needs to be educated about the risk factors, symptoms and importance of early detection of lung cancer through intensive public and social media campaigns, the doctors added.