A new study presents this not-so-surprising fact: Nine out of every 10 cells in the lungs of smokers show some degree of mutation, reports the AFP. But then came the surprise: The lungs of former smokers seem to be able to repair some of the damage, according to the study in Nature. How this happens isn't clear. In fact, a researcher uses the word "magically" to describe the healing to the BBC: "There is a population of cells that, kind of, magically replenish the lining of the airways," says Peter Campbell of the UK's Wellcome Sanger Institute. As the researchers describe it, the few cells that are able to avoid mutation in smokers' lungs "exist in a nuclear bunker," but they are able to grow and replace damaged cells if the smoker quits.
This held true for people who had smoked 15,000 packs over a span of decades, says Campbell in a statement. "Within a few years of quitting, many of the cells lining their airways showed no evidence of damage from tobacco." One big caveat: The study sample was small, based on the lung biopsies of only 16 people, not all of whom were smokers. Still, a story in Nature says that "perhaps the most surprising result" of the study is that for five out of six former smokers, 20% to 50% of their cells "had a low mutation burden that was similar to the profile of non-smokers of the same age range." Campbell says the results refute a common-held idea among smokers that it's pointless to quit because damage is permanent. The study shows "it's never too late to quit," he says. (Read more lungs stories.)