Toronto, Feb 11 (IANS): Long-term smoking could cause thinning of a vital brain part in which critical cognitive functions such as memory, language and perception take place, a new study has warned.

Smoking appears to accelerate the thinning of the brain's cortex, the outer layer of the brain. A thinner brain cortex is associated with adult cognitive decline.

"Smokers should be informed that cigarettes could hasten the thinning of the brain's cortex, which could lead to cognitive deterioration," said the study's lead author Sherif Karama, assistant professor of psychiatry at the McGill University in Canada.

Stopping smoking helps to restore at least part of the cortex's thickness, the findings showed.

The study involved 244 male and 260 female participants with average age of 73. All the participants were examined as children in 1947 as part of the Scottish Mental Survey.

"We found that current and ex-smokers had, at age 73, many areas of thinner brain cortex than those that never smoked. Subjects who stopped smoking seem to partially recover their cortical thickness for each year without smoking," Karama pointed out.

The apparent recovery process is slow, however, and incomplete.

Heavy ex-smokers in the study who had given up smoking for more than 25 years still had a thinner cortex, the study, published in the journal Molecular Psychiatry, added.