New Study Reveals How Smoking May Increase Dementia Risk via Lung-Brain Communication

Smoking’s Hidden Link to Dementia: A New Lung-Brain Connection

New research suggests that smoking cigarettes may increase the risk of dementia by triggering harmful chemical signals that travel from the lungs to the brain. The findings, published in Science Advances, provide deeper insight into the well-documented but poorly understood relationship between smoking and neurodegenerative diseases.

Decades of Evidence Linking Smoking and Dementia

A 2011 study found that heavy smoking in midlife more than doubled the risk of developing Alzheimer’s disease and other forms of dementia decades later. While previous theories focused on smoking’s impact on the vascular and respiratory systems—such as reduced oxygen flow to the brain—the new research identifies a previously unknown mechanism involving nicotine-triggered miscommunication.

How Nicotine Disrupts Brain Health via the Lungs

The study reveals a direct pathway from the lungs to the brain through pulmonary neuroendocrine cells (PNECs). When exposed to nicotine, these rare cells release exosomes—tiny particles that transport cellular waste—which disrupt iron balance in neurons. This disruption may contribute to cognitive decline and dementia-like symptoms.

“This research establishes a clear ‘lung-brain’ axis that helps explain why cigarette smoking is linked to cognitive decline and neurodegenerative risks.”

The researchers found that PNECs, which make up less than 1% of lung cells, release exosomes rich in serotransferrin—a protein that regulates iron flow in the bloodstream. This suggests that with every puff of a cigarette, cigar, or vape, the lungs release materials that could affect brain health.

“We are finding neurodegeneration-related markers, which are going up, and which can be linked with many cognitive and dementia-related diseases.”

The Challenge of Studying Rare Lung Cells

PNECs are uniquely challenging to study because they are extremely rare and blend the functions of nerve and endocrine cells. To overcome this, the team generated induced PNECs (iPNECs) from human pluripotent stem cells, allowing them to observe the effects of nicotine exposure in a controlled setting.

“The primary challenge was the extreme rarity of PNECs, which make up less than 1% of lung cells, making them nearly impossible to isolate and study in depth.”

According to the study’s corresponding author, Assistant Professor Joyce Chen of UChicago’s Pritzker School of Molecular Engineering, the findings redefine the lung’s role in health and disease.

“It reveals that the lung is not just a passive target of smoke exposure, but an active signaling organ influencing brain pathology.”

Implications for Future Research and Public Health

The discovery of this lung-brain communication pathway opens new avenues for protecting neurons from smoke-induced damage. While further research is needed to confirm causality, the findings underscore the urgent need for smoking cessation programs and public health interventions to reduce dementia risk.

The study was conducted by researchers at the University of Chicago, including collaborators from the Pritzker School of Molecular Engineering and the Ben May Department for Cancer Research.