Scientists studied the lungs of ex-smokers cell by cell. What they found was unsettling - Newsweek

What the report says

Newsweek reported on new research from McGill University in Montreal examining why people who have stopped smoking can remain at elevated risk for smoking-related lung disease. The study, led by senior author Carolyn Baglole of McGill’s Department of Pharmacology and Therapeutics and the Research Institute of the McGill University Health Center, explored why quitting can improve lung health while not necessarily returning the lungs to the condition of someone who never smoked.

According to Newsweek, the team analyzed publicly available single-cell data covering more than 100,000 lung cells from nine never-smokers, seven former smokers and five current smokers. The analysis, published in Translational Research, looked across more than 40 lung cell types to compare molecular activity associated with ongoing smoking, smoking cessation and no smoking history.

The researchers found that some lung cells showed signs of recovery after people quit, but other cells retained molecular changes tied to tissue structure, immune responses and blood vessel health. Newsweek also reported that some former smokers showed patterns not found in either current smokers or never-smokers, which the researchers said could point to a distinct biological imprint left after cessation.

The findings matter because smoking is a major risk factor for lung cancer and chronic obstructive pulmonary disease, and former smokers still face higher risk than people who never smoked. The McGill researchers said the next step is to understand why certain lung cells do not fully rebound, with the broader goal of identifying ways to support lung repair and reduce smoking-related disease risk.