By causing the brain to lose volume, smoking causes premature aging and increases the risk of dementia.
- Study finds that smoking accelerates brain shrinkage, causing premature aging and increasing the risk of cognitive decline and Alzheimer’s disease.
- To date, France still has nearly twelve million daily smokers, while tobacco remains the leading cause of avoidable mortality in the country, with 75,000 deaths attributable in 2015.
- Alzheimer’s disease affects 1.2 million people in France today, according to Health Insurance. Rare before the age of 65, the disease affects 23% of the population after the age of 80, and affects approximately twice as many women as men.
As we age, our brain naturally loses volume compared to its original optimal size. It’s like that, you can’t escape it. But certain lifestyles, especially avoidable ones, can aggravate the process and intensify the shrinkage of our gray matter. This is particularly the case with smoking, thus causing premature aging of the brain and increasing the risk of age-related cognitive decline and Alzheimer’s disease, according to a recent study published in the journal Biological Psychiatry.
The more cigarettes a person smokes, the smaller their brain becomes
“Until recently, scientists have neglected the effects of smoking on the brain, in part because they have focused on its toll on the lungs and heart.”explains psychiatrist Laura J. Bierut, lead author of the study, in a communicated. It has long been known that there is a link between tobacco consumption and small brain size, but the reasons for this association remain unclear.
To sort out fact from fiction, researchers from the University of Washington (United States) analyzed data from some 40,000 adult volunteers from the UK Biobank, including their brain volume imaging and smoking history. and their genetic risk of smoking, half of smoking behavior being hereditary.
As a result, each pair of data was found to be linked: smoking history and brain volume, genetic smoking risk and smoking history, and finally genetic smoking risk and brain volume. Notably, the association between smoking and brain volume was dose-dependent: the more cigarettes per day a person smoked, the smaller their brain.
A shrinking of the brain “irreversible” and dementia risk factor
When all three factors were considered together, the association between genetic smoking risk and brain volume disappeared, while the link between each of them and smoking behavior remained. Using a statistical approach known as mediation analysis, the researchers were then able to “determine the sequence of events: genetic predisposition leads to smoking, which leads to a decrease in brain volume.”
And, unfortunately, the shrinkage would “irreversible”according to Laura J. Bierut: even people who had stopped smoking years before had gray matter that was definitely less voluminous than that of participants who had never tried cigarettes. “You certainly cannot undo the damage that has already been done to your brain, concludes the researcher, but by quitting smoking, you can avoid causing others.” and unnecessarily putting you at increased risk of dementia.
