If you’re a smoker, the findings of this new study will make you want to quit. (Photo: Getty Images)

As if cancer, premature aging, gum disease, lung disease, Alzheimer’s disease, and heart disease weren’t reasons enough to quit smoking, a new study shows yet another scary effect of lighting up: Thinning of the cortex, the brain’s outer layer.

While the cortex is known to thin as a person ages, that thinning seems to be accelerated in smokers. This part of the brain is where functions such as memory, language, and perception take place — and a thinning cortex is associated with cognitive decline.

Related: Quitting Smoking May Bring Mental Health Benefits

For the study, published in the journal Molecular Psychiatry, researchers looked at health data and MRI brain scans of 244 men and 260 women with an average age of 73; some of the people in the study were current smokers, some were ex-smokers, and some were non-smokers.

The brain cortices of the current and ex-smokers were thinner than those who had never smoked before, researchers found. But the good news: People who did smoke but quit the habit seemed to “partially recover their cortical thickness for each year without smoking,” study researcher Sherif Karama, MD, assistant professor of psychiatry at McGill University, said in a statement.

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However, Karama did add that even though researchers saw signs of recovery, the process seemed to be slow, and the former smokers’ cortices were still thinner than those who never smoked.

Previously, research out of the University of California, Los Angeles, showed that smoking during young adulthood seems to thin a specific part of the brain cortex, called the insula. The insula plays a role in decision-making and monitoring internal states; it’s also the part of the brain with the highest density of nicotinic acetylcholine receptors, meaning it has a strong role in tobacco dependence.

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The findings come at the same time as those of another study that examined health data from nearly one million people over approximately 10 years, showing that in the U.S., tobacco is to blame for an additional five diseases and 60,000 deaths a year, the New York Times reports. The five diseases found to be newly linked with tobacco use include kidney disease, infection, intestinal disease from blood flow problems, and heart and lung diseases that, before, were not previously linked with tobacco use.

"A substantial portion of the excess mortality among current smokers between 2000 and 2011 was due to associations with diseases that have not been formally established as caused by smoking," the authors of the study, which appeared in The New England Journal of Medicine, wrote. “These associations should be investigated further and, when appropriate, taken into account when the mortality burden of smoking is investigated.”

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