Decline in sense of smell is connected to faster buildup of Alzheimer’s disease-related pathology seen in brain scans, according to new research focused on older adults who live outside of nursing homes. The findings provide additional evidence that loss of smell (known as anosmia) is a key early sign of Alzheimer’s-related cognitive impairment and the accumulation of associated harmful proteins, such as amyloid-beta and tau. The research, led by NIA scientists, was published in the Journal of Alzheimer’s Disease.
Decline in sense of smell had previously been confirmed as an early warning sign for Alzheimer’s in both human and animal studies, but its connection to the uptick of dementia-related brain imaging biomarkers over time had not been as closely studied in larger populations of older adults. For this study, the team tracked 364 participants from the Baltimore Longitudinal Study of Aging (BLSA) over an average period of about 2.5 years. The NIA-led BLSA is the longest running study of healthy aging in America.