ArticleNeurology2019
Impaired olfaction is associated with cognitive decline and neurodegeneration in the brain.
Article in Neurology, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 142 papers, 4 of them syntheses that pooled it.
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The trial behind it
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Who cites it
142 citing papers in PubMed, 4 syntheses or guidelines pooled it, 225 citations in OpenAlex.
- Olfactory Impairment and Incident Cognitive Decline: A Systematic Review and Meta-Analysis.International forum of allergy & rhinology · 2025Pooled it
- Olfaction and declarative memory in aging: a meta-analysis.Chemical senses · 2023Pooled it
- Prognosis and persistence of smell and taste dysfunction in patients with covid-19: meta-analysis with parametric cure modelling of recovery curves.BMJ (Clinical research ed.) · 2022Pooled it
- Association of Odor Identification Ability With Amyloid-β and Tau Burden: A Systematic Review and Meta-Analysis.Frontiers in neuroscience · 2020Pooled it
- Predictors of Improvement after Cognitive Training in Mild Cognitive Impairment: Insights from the Cognitive Training and Neuroplasticity in Mild Cognitive Impairment Trial.Alzheimer disease and associated disordersTrial
- Hearing Loss and Parkinson's Disease: Insights From Human and Animal Studies.Brain and behavior · 2026Article
- Single odor identification in subjective cognitive decline, mild cognitive impairment and Alzheimer's dementia.Wiener klinische Wochenschrift · 2026Article
- Sensory decline in aging and neurodegeneration: A mitochondrial perspective.Pharmacological research · 2026Review
- Olfactory impairment associated with cognitive decline: findings from cognitive domain assessments among older adults in West Jakarta, Indonesia.BMC geriatrics · 2026Article
- Age-related cognitive decline in house crickets reveals conserved patterns of sensory and learning deficits across the lifespan.GeroScience · 2026Article
- Longitudinal evaluation of neurocognitive outcomes in a cohort with persistent post-COVID olfactory dysfunction.Scientific reports · 2026Article
- Elucidating the burden of dual-sensory impairment in community-based older individuals in a multi-ethnic society.Scientific reports · 2026Article
- Olfactory decline tracks central-to-peripheral spread of tau pathology in Alzheimer's disease.Alzheimer's & dementia : the journal of the Alzheimer's Association · 2026Article
- Article
- Evaluating methods for quantitative olfactory assessment: a comparative longitudinal analysis of Sniffin' Sticks and alternative tools.Chemical senses · 2026Article
- Characterizing olfaction, anxiety, and depression in subjective cognitive decline.Journal of Alzheimer's disease : JAD · 2026Article
- Racial and ethnic differences in the associations of sensory impairments with cognition in older United States adults.Journal of Alzheimer's disease : JAD · 2026Article
- Olfactory and Cognitive Performance Improvement After Oxygen-Ozone Major Autohemotherapy in Mild Cognitive Impairment: A Retrospective Cohort Study.Neurology international · 2026Article
- Evaluating effects of aging on dog olfactory performance.GeroScience · 2026Article
- Review
82 more citing papers are in PubMed but not listed here.
Corrections and comments
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Authors and funding
8 authors at 1 institution in 3 countries.
Funding
Abstract
objectiveWe aimed to examine whether impaired olfaction is associated with cognitive decline and indicators of neurodegeneration in the brain of dementia-free older adults.
methodsWithin the Rush Memory and Aging Project, 380 dementia-free participants (mean age = 78 years) were followed for up to 15 years, and underwent MRI scans. Olfactory function was assessed using the Brief Smell Identification Test (B-SIT) at baseline, and categorized as anosmia (B-SIT <6), hyposmia (B-SIT 6-10 in men and 6-10.25 in women), and normal (B-SIT 10.25-12 in men and 10.5-12 in women). Cognitive function was annually assessed with a battery of 21 tests, from which composite scores were derived. Structural total and regional brain volumes were estimated. Data were analyzed using linear regression and mixed-effects models.
resultsAt study entry, 138 (36.3%) had normal olfactory function, 213 (56.1%) had hyposmia, and 29 (7.6%) had anosmia. In multiadjusted mixed-effects models, hyposmia (β = -0.03, 95% confidence interval [CI] -0.05 to -0.02) and anosmia (β = -0.13, 95% CI -0.16 to -0.09) were associated with faster rate of cognitive decline compared to normal olfaction. On MRI, impaired olfaction (hyposmia or anosmia) was related to smaller volumes of the hippocampus (β = -0.19, 95% CI -0.33 to -0.05), and in the entorhinal (β = -0.16, 95% CI -0.24 to -0.08), fusiform (β = -0.45, 95% CI -0.78 to -0.14), and middle temporal (β = -0.38, 95% CI -0.72 to -0.01) cortices.
conclusionImpaired olfaction predicts faster cognitive decline and might indicate neurodegeneration in the brain among dementia-free older adults.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.