PARIS, Dec 8 (AFP) - Smoking has long been known to cause cancer, heart disease, impotence and so on -- now, damage to your IQ can be added to the list.
Researchers in Scotland assessed the mental abilities of 465 people who had been enrolled in an IQ test at the age of 11 in 1947.
The volunteers were tested again between 2000 and 2002, when they were 64 years old. Roughly half of them were smokers.
"Smokers performed significantly worse in five different cognitive tests than did both former smokers and those who had never smoked," the British weekly New Scientist reports in next Saturday's issue.
"When social and health factors such as education, occupation and alcohol consumption were taken into account, smoking still appeared to contribute to a drop in cognitive function of just under one percent."
The study, published in full in a specialist journal, Addictive Behaviours, was led by Lawrence Whally of the University of Aberdeen.
Why smoking could affect cognitive ability is unclear. One possible reason is that, in later life, brain cells are more susceptible to damage by rogue atoms called free radicals, which could be unleashed by the chemicals in tobacco smoke.
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