New research suggests that smoking could cause thin out a vital part of the brain, according to a recent study.

Researchers at McGill University and the University of Edinburgh found that smoking causes the thinning of the brain cortex, or the outer layer of the brain in which critical cognitive functions such as memory, language and perception take place.

"We found that current and ex-smokers had, at age 73, many areas of thinner brain cortex than those that never smoked," Dr. Sherif Karama, lead author of the study, said in a statement. "Subjects who stopped smoking seem to partially recover their cortical thickness for each year without smoking."

For the study, researchers collected data from 244 males and 260 female subjects with the average age of 73. The test group included current smokers, ex-smokers and non-smokers. All of the subjects were examined as children in 1947 as part of the Scottish Mental Survey. Researchers used health data gathered during recent personal interviews with the subjects, and also analyzed data from MRI scans showing the current state of the subjects' brain cortices.

Though the cortex grows thinner with normal aging, the study found that smoking appears to accelerate the thinning process. 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. Cortical thinning seems to persist for many years after someone stops smoking," Dr. Karama said.

The findings are detailed in the journal Molecular Psychiatry.