Smoking accelerates normal brain ageing in ways that can impair thinking skills such as planning, decision-making and problem-solving, research has shown.
The good news is that it might be possible to reverse the harmful effects by giving up the habit, even late in life, say scientists.
Researchers analysed brain scan data on 504 men and women with an average age of 73.
Around half the participants were former or current smokers while the rest had avoided tobacco all their lives.
The findings showed that smoking appeared to increase the rate at which the outer layer of the brain, or cerebral cortex, thins with age.