12/10/2025
https://www.facebook.com/share/1D3tviKrr7/
Studies have identified a diminished sense of smell as a potential early warning sign of Alzheimer's disease. Researchers at the University of Chicago found that individuals carrying the APOE e4 gene, a known risk factor for Alzheimer's, exhibited a 37% higher likelihood of experiencing olfactory dysfunction by age 65. This decline in smell detection was observed even before noticeable memory issues emerged.
Further investigations revealed that in early Alzheimer's stages, immune cells in the brain, known as microglia, may mistakenly attack neural connections between the olfactory bulb and the locus coeruleus, a brainstem region crucial for sensory processing. This damage disrupts the brain's ability to process smells, potentially leading to anosmia (loss of smell). These findings suggest that olfactory dysfunction could precede cognitive decline and serve as an early biomarker for Alzheimer's disease.
Experts emphasize that while a reduced sense of smell can be a normal part of aging, its occurrence in conjunction with other risk factors may warrant further evaluation. Simple at-home smell tests are being explored as non-invasive tools for early detection of cognitive impairment, offering a promising avenue for identifying individuals at risk of Alzheimer's disease before clinical symptoms appear.
Research Paper 📄
DOI: 10.1038/s41467-025-62500-8