Rising air pollution, changes in hormone levels, immune system imbalances and longer life expectancy are increasing the risk of lung cancer in women who have never touched a cigarette.

Lung cancer cases are increasing in people who have never smoked, especially in women, a new study by the World Health Organization’s cancer agency has found.

The findings, published in The Lancet Respiratory Medicine, reveal that lung adenocarcinoma, the most common type of lung cancer among non-smokers, accounts for nearly 60% of lung cancer cases in women compared to 45% in men.

About 2.5 million new lung cancer cases were diagnosed worldwide in 2022 – an increase of 300,000 since 2020. The study suggests that environmental factors, particularly air pollution, along with genetic predisposition and immune responses, may be driving this rise in non-smoking-related lung cancer.