Another reason to quit smoking: It increases the risk of dementia due to brain shrinkage – but quitting, at any age, helps

She admits that scientists once paid less attention to the effects of tobacco on the brain, “partly because we were focused on all the terrible effects of tobacco on the lungs and the heart.”

As we become increasingly concerned about brain healthand I started looking at the brain more closely, it became clear that smoking is also very bad for the brain, she says.

“People who smoke are more likely to have gray and white matter deterioration,” adds Bierut, noting that this may help explain why some researchers estimate that 14 percent of global pollution Alzheimer’s disease cases are linked to smoke cigarettes.

Studies show smoking damages the brain as well as the heart and lungs. The habit is linked to brain shrinkage, which causes memory loss – a hallmark of dementia. Photo: Shutterstock — Studies show that smoking damages the brain as well as the heart and lungs. This habit is linked to brain shrinkage, which leads to memory loss – a hallmark of dementia. Photo: Shutterstock

A Swedish study on smoking and the brain examined women’s brains and smoking habits over more than 30 years. Smoking has been found to be associated with frontal lobe shrinkage.

The frontal lobe is responsible for managing many elements of thought and behavior, including emotions, personality, judgment, and self-control. It also supports in-memory storage. And memory loss is an early marker of dementia.

Dr. Joshua Gray, associate professor in the departments of medical and clinical psychology and neuroscience at the Uniformed Services University in Washington, led a large study in 2020 on the effects of smoking on the brain.

Quitting smoking at an early age (40) can reduce excess mortality by 90 percent. In other words, the risks are reduced to levels only slightly higher than those of non-smokers.

Dr. Joshua Gray, assistant professor of medical and clinical psychology and neuroscience

The findings, he says, suggest that smoking is one of the main risk factors for dementia, associated with a 1.6 times higher likelihood of developing the disease.

“It exerts many detrimental effects through oxidative stress,” he says. Inflammation and atherosclerotic processes such as hardening of the arteries can result in brain atrophy, as the studies mentioned above and dozens of others have shown.

Atherosclerosis is the thickening or hardening of the arteries caused by buildup in the vessel walls.

“We found in our study that smoking was linked to a reduction in gray matter and an increase in white matter hyperintensity,” that is, lesions, explains Gray. The lesions are closely linked to a higher risk of dementia and stroke. (White matter describes the nerve fibers that connect different areas of the brain to each other and to the spinal cord.)

White matter describes the nerve fibres that connect different areas of the brain to each other and to the spinal cord. Photo: Shutterstock — The white matter describes the nerve fibers that connect the different areas of the brain to each other and to the spinal cord. Photo: Shutterstock

The brain consumes 20 percent of the oxygen the body needs to function. It is particularly vulnerable to oxidative stress – an imbalance between harmful free radicals and the body’s natural defense mechanisms – which damages structures inside brain cells and can cause cell death.

Oxidative stress also disrupts the balance of essential proteins, such as beta-amyloid peptides. Studies suggest that it contributes to accumulation of amyloid plaque in the brain it is a marker of Alzheimer’s disease.

Inflammation is cited as the cause of many diseases, including dementia; experts speak of brain “inflammation” – aging accelerated by inflammation.

Atherosclerosis impairs blood flow, which can have serious consequences for brain health for obvious reasons: it deprives the brain of oxygen and important nutrients, leading to a risk of vascular dementia.

The US Food and Drug Administration says there are more than 7,000 chemicals in cigarettes and cigarette smoke. Image: Shutterstock — The U.S. Food and Drug Administration says cigarettes and cigarette smoke contain more than 7,000 chemicals. Image: Shutterstock

Chemicals inhaled from smoking (and second-hand smoke) damage blood vessels, increasing the risk of developing atherosclerosis.

According to the U.S. Food and Drug Administration, cigarettes and cigarette smoke contain more than 7,000 chemicals. Nicotine and tar are the most mentioned. Others include acetone, found in nail polish remover; arsenic, used in rat poison; and lead, present in batteries.

A pregnant woman who smokes can harm not only her brain, but also that of her unborn child. A 2023 study published by researchers at the University of California, Irvine found that gestational nicotine disrupts receptors that support and regulate central nervous system activity.

Smoking while pregnant harms not only the mother-to-be, but also the unborn child. Studies show tobacco smoke exposure in pregnancy is linked to smaller brains in newborns. Photo: Shutterstock — Smoking during pregnancy not only harms the expectant mother, but also the unborn child. Studies show that exposure to tobacco smoke during pregnancy is linked to smaller brains in newborns. Photo: Shutterstock

Exposure to tobacco smoke during pregnancy has been associated with smaller head circumference at birth, reflecting the smaller size of the newborn brain, which may affect long-term brain development.

“Stopping smoking at an early age (40) can reduce excess mortality by 90 percent,” he says. “In other words, the risks are reduced to levels only slightly higher than those of non-smokers.

“Even quitting smoking after age 60 has been shown to significantly reduce the risk of dementia. »