Smoking raises dementia risk: Scientists discover nicotine’s hidden lung–brain link

April 17, 2026
The researchers found a previously unmapped route from the lungs to the mind through pulmonary neuroendocrine cells (PNECs). When exposed to nicotine, these cells release exosomes—tiny particles that transport cellular products and waste—that disrupt the iron balance in neurons, triggering symptoms often found in dementia patients.