The new MRI research reveals that heavy smoking can shrink the basic areas of the brain associated with memory and knowledge and overweight can exacerbate damage, creating new questions about prevention of dementia.
Study: Smoking predicts brain atrophy in 10,134 healthy people and is possibly influenced by body mass index. Credit Picture: Fongbeerredhot/Shutterstock.com
A recent study at Dementia npj Investigated the relationship between smoking and brain atrophy and if the body mass index (BMI) affects this correlation. The study found that smokers had significantly lower gray and white brain volumes than non -smokers. When the BMI was included in statistical models, the relationship between the smoking package and the loss of brain volume decreased, indicating a possible effect mediated rather than direct causal relevance.
Neurodegenerative disorder: dominance and risk factors
A neurodegenerative disorder occurs when nerve cells in the brain and the nervous system gradually lose their function, resulting in a reduction in physical and cognitive abilities. Alzheimer’s disease (AD) is the most common type of dementia, which affects memory, cognitive function and behavior.
An increased prevalence of dementia worldwide has been recorded. A recent study has estimated that about 47 million people around the world have been diagnosed with dementia. This number is expected to increase by 10 million new cases each year.
Many studies have identified the risk factors of early, medium life and late life for dementia. Smoking is a risk factor that contributes up to 14% of dementia cases worldwide. Toxins present in cigarette smoke can cause nephew, a mechanism closely associated with AD. In addition to dementia, previous research has also shown that cigarette smokers are at high risk of many diseases, such as cerebrospinal disease and respiratory diseases.
While previous post-analyzes have linked smoking to the increased risk of dementia, few large-scale studies have examined how the history and intensity of smoking are directly related to the atrophy of the brain with magnetic resonance (MRI), a biomarker. To assess this, the correlation between smoking and brain atrophy and the loss of brain tissue from shrinking or death of neurons with reduced neuronic connections must be evaluated.
Researchers generally monitor brain atrophy for AD and other neurodegenerative disorders through neuroimaging by t1 loss in t1-established structural imaging, which differs from aging. Magnetic resonance imaging is performed for the evaluation of the loss of stroke, a biomarphy of neurodegeneration.
Not many large -scale studies have been explored the correlation between smoking atrophy and brain -based brain loss measured by magnetic resonance imaging, which could play a decisive role in determining the way in which smoking contributes significantly.
For the study
The current study examined the assumption that people with a history of smoking face higher brain atrophy throughout the brain and regional lobar levels than non -smokers.
A total of 10,134 participants from four study positions, aged 18 to 97 years, were selected for this study. All participants underwent a non -opposite MRI scan of the whole body. Prior to the depiction, questionnaires were completed, from which demographics, medical history and smoking regime were completed. Each participant provided information on the number of packages that smoke per day and the number of years they smoke.
Based on the questionnaire answers, participants were grouped as the smoking group (a non-zero-year-year) and non-smokers group (zero packaging years). Packaging years correspond to a measure of exposure to tobacco to evaluate the history of smoking and related risks. The smoking team included 3,292 participants, while the non -smokers group included 6,842 people.
The current study used the Fastsurfer network, an extensively validated deep learning conductor, to quantify brain tumors from 3D T1 scans. A deep learning model was also used for the intracranial tumor sector (ICV).
A regression analysis was carried out in smokers to explore the relationship between the years of smoking packages and brain areas in two different models: Model 1 (adapted to age, gender and study position) and model 2 (adapted to age, gender, site and BMI).
Study findings
Compared to the non -smokers group, participants belonging to the smoking group were more often women, Caucasian, had a higher BMI, were higher and had higher rates of type 2 diabetes and hypertension. The smoking team had an average package year of 11.93.
Groupwise regional comparisons have revealed lower brain volumes in smoking against non -smoking groups. A bilateral PEARSON correlation showed a moderately positive correlation between the highest BMI and the increased years of smoking packages. Comparing Model 1 and Model 2, the current study observed the weakening of the statistical significance and the sizes of the results in 11 areas of the brain when the BMI was added, indicating a possible but not definitively proven, BMI mediation to the correlation between the increase in the increasing packets.
It is important that smokers have still shown significant atrophy in multiple areas, including areas related to Alzheimer’s disease, such as hippocampus, posterior textile and precuneus, even when adapted to BMI.
Conclusions
The current study revealed that people with a history of smoking and higher chronic smoking packages had brain atrophy. Preliminary findings also show that the BMI could play a dynamic and exploratory role in the correlation between smoking and the loss of brain tumor. Therefore, obesity and smoking are two risk factors that could be exploited in the future to prevent dementia, including ad.
In the future, more research is needed to examine the possible mediation effects of the volume of white matter hypertension and brain atrophy on smoking history and packages of packages.
The basic power of this study lies in the analysis of a large coorde with a history of smoking and quantitative structural representation. In addition, it allowed the measurement of the peripheral brain volume at risk for the pathology of AD, such as the hippocampus, the posterior textile and the precuneus.
Despite the strengths, the design of a transverse section limited the authors’ ability to complete the causal relevance. The design of the study did not have the time analysis required for reliable mediation or moderation test. In addition, the study did not include Alzheimer’s cognitive tests or biomarkers, such as amyloid or tau, which limits the ability to directly connect brain atrophy. Therefore, the role of the BMI in the relationship between smoking and brain atrophy requires a more timeless analysis for validation.
Magazine report:
- Meysami, S. et al. (2025). Smoking predicts brain atrophy in 10,134 healthy individuals and is possibly affected by the body mass index. Dementia npj. 1 (1), 1-7. https://doi.org/10.1038/s44400-025-00024-0. https://www.nature.com/articles/S44400-025-00024-0