THURSDAY, Aug. 4, 2022 (HealthDay News) -- Rapid olfactory decline during normal cognition may be a simple biomarker for early Alzheimer disease in older adults, according to a study published online July 28 in Alzheimer's & Dementia.
Rachel R. Pacyna, from the Pritzker School of Medicine at the University of Chicago, and colleagues assessed if the rate of olfactory decline during normal cognition predicts subsequent Alzheimer disease diagnoses and brain dysmorphology. The analysis included 515 older adults with up to 18 years of annual exams.
The researchers found that faster olfactory decline during periods of normal cognition predicted higher incidence of subsequent mild cognitive impairment or dementia (odds ratio, 1.89), which was comparable to carrying an APOE-ε4 allele. Additionally, faster olfactory decline during normal cognition was associated with smaller gray matter volumes on MRI in Alzheimer disease and olfactory brain regions.
"We have to take our study in the context of all of the risk factors that we know about Alzheimer's, including the effects of diet and exercise," a coauthor said in a statement. "Sense of smell and change in the sense of smell should be one important component in the context of an array of factors that we believe affect the brain in health and ageing."