Smoking cigarettes has long been linked to health issues involving the mouth, lungs and chest. However, a new study has found another negative effect of the harmful habit — this time, involving a smoker's brain.
Researchers out of Washington University School of Medicine in St. Louis, Missouri, found smoking causes the brain to shrink, and stopping smoking doesn't restore it to its original size. And since brains naturally lose volume as a person ages, smoking effectively speeds up the brain's aging process, possibly explaining why older smokers are at a higher risk of having Alzheimer's disease and dementia.
"It sounds bad, and it is bad," said senior author Dr. Laura J. Bierut, alumni-endowed professor of psychiatry. "A reduction in brain volume is consistent with increased aging. This is important as our population gets older because aging and smoking are both risk factors for dementia."
The findings, published in Biological Psychiatry: Global Open Science, were a result of comparing 32,094 smokers' smoking history, brain imaging, genetic predisposition and other health data points.
Ultimately, researchers found genetic risk leads to smoking, which leads to decreased brain volume. Plus, the more a person smokes each day, or with each additional year of smoking, the smaller their brain volume compared to less frequent smokers or those who don't smoke at all.
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"People who smoke are more likely to have deterioration in gray and white matter, which provides a possible explanation as to why 14% of global Alzheimer's disease cases could be attributable to cigarette smoking," the study states. "However, a significant question remains about whether these associations represent predisposing features for the risk of developing cigarette smoking or are consequences of cigarette smoking."
And although stopping smoking stops the brain from shrinking, researchers found smokers who quit still had permanently smaller brains years later, meaning the brain damage is irreversible.
"You can't undo the damage that has already been done, but you can avoid causing further damage," Chang said. "Smoking is a modifiable risk factor. There's one thing you can change to stop aging your brain and putting yourself at increased risk of dementia, and that's to quit smoking."
The CDC has a long list of resources for those hoping to quit smoking, including a phone number, text messaging service and a smartphone app. Click here for more help in managing withdrawal symptoms or to learn about medicines to help you quit.
