Smoking not only damages health, it is bad for the brain too, according to a Scottish study spanning nearly 60 years.

Professor Lawrence Whalley and his team looked at how the cognitive abilities of 465 people, half of them smokers, changed over their lifetime.

They were first tested in 1947, at 11 years old and examined again between 2000 and 2002 when they were 64.

Smokers performed significantly worse in five different cognitive tests than did both former smokers and those who had never smoked.

When social and health behavior was taken into account - factors like education, occupation and alcohol consumption - smoking still appeared to contribute to a drop in cognitive function of just less than 1 percent.

The link between cognitive aging and impaired lung functions could be that smoking subjects the vital organs, including the brain, to oxidative stress, suggests Whalley, of the Department of Mental Health at the University of Aberdeen.

The study he and colleagues at the University of Edinburgh produced appears in New Scientist magazine.