‘It’s never too late’

Smokers can effectively turn back time in their lungs by kicking the habit, with healthy cells emerging to replace some of their tobacco-damaged and cancer-prone ones, a new study shows.

Smokers have long been told their risk of developing diseases like lung cancer will fall if they can quit, and stopping smoking prevents new damage to the body.

But a study published yesterday in the journal Nature found that the benefits may go further, with the body appearing to draw on a reservoir of healthy cells to replace smoke-damaged ones in the lungs of smokers when they quit.

The study’s joint senior author, Peter Campbell of the Wellcome Sanger Institute, said the results should give new hope to smokers who want to quit.

“People who have smoked heavily for 30, 40 or more years often say to me that it’s too late to stop smoking -- the damage is already done,” he said in a statement issued by the institute. “What is so exciting about our study is that it shows that it’s never too late to quit.”

Some of the people in the study had smoked more than 15,000 packs of cigarettes in their life, he said.

The precise mechanism by which that replacement occurs is not yet clear, but the study’s authors believe there may be a sort of reservoir of cells, waiting for a chance to emerge.