Smoking affects brain volume finds a new study

Smoking among the young has increased drastically among the younger population and this habit is often related to lung and heart problems but its association with brain was not well known.

Several studies have shown that brain volume is negatively associated with cigarette smoking, but there is an ongoing debate about whether smoking causes lowered brain volume or a lower brain volume is a risk factor for smoking.

A study carried out by scientists at the University of Washington, United States, showed that smoking also affects the brain, being related to the appearance of Alzheimer's and dementia, a specialized magazine published. 

Researchers looked at the consequences of tobacco use at the brain level, and their findings help explain why smokers are at high risk of age-related cognitive decline and Alzheimer’s disease, according to an article in Biological Psychiatry: Global Open Science. A history of daily smoking is strongly associated with a decreased total brain volume.

With the aim of unraveling the relationship between genetics, brain and behavior, the authors of the research analyzed data extracted from the UK Biobank, on the health and behavior of half a million people, mostly of European descent.

The team analyzed de-identified data on brain volume, smoking history and genetic risk of smoking from 32,094 people.

They were able to show that each pair of factors were related: smoking history and brain volume; genetic risk of smoking and history of smoking; and genetic risk of smoking and brain volume. Furthermore, the association between smoking and brain volume was dose-dependent: the more packs a person smoked per day, the smaller their brain volume.

When all three factors were considered together, the association between genetic risk for smoking and brain volume disappeared, while the link between each of them and smoking behaviors remained.

Using a statistical approach known as mediation analysis, the researchers determined the sequence of events: genetic predisposition leads to smoking, which leads to a decrease in brain volume.

Reference: Yoonhoo Chang, Vera Thornton, Ariya Chaloemtoem et al; Investigating the Relationship Between Smoking Behavior and Global Brain Volume; Biological Psychiatry: Global Open Science, | VOLUME 4, ISSUE 1, P74-82, JANUARY 2024.