Olfactory dysfunction in dementia

Alves, Jorge; Petrosyan, Agavni; Magalhães, Rosana

doi:10.12998/wjcc.v2.i11.661

Cited by 81 publications

(87 citation statements)

References 59 publications

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“…5,23,[27][28][29] Although the exact inception point of AD pathology in the olfactory system remains unknown, the disease course progressively involves 29 multiple levels of the olfactory system, 27,30 including peripheral structures such as the olfactory bulb and epithelium, as well as higher order olfactory pathways connected to cognitive processes. 25 Studies have shown greater OI deficits in patients with AD compared to those with vascular dementia, 31,32 suggesting that the site of vascular pathology may determine the type and severity of olfactory deficit, 33 with specific olfactory deficits observed only in patients whose corresponding olfactory structures sustained vascular damage, in contrast to the multiple-level impairment observed across the olfactory system in AD pathology. 25,27,30 Because we did not have detailed information on dementia subtype in this study, we could not investigate this further.…”

Section: Resultsmentioning

confidence: 99%

Olfaction and risk of dementia in a biracial cohort of older adults

et al. 2017

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Objective: Prior studies indicate that olfactory function may be an early marker for cognitive impairment, but the body of evidence has been largely restricted to white populations. Methods:We studied 2,428 community-dwelling black and white older adults (baseline age 70-79 years) without dementia enrolled in the Health, Aging, and Body Composition (Health ABC) study. Olfaction was measured as odor identification (OI) with the 12-item Cross Cultural Smell Identification Test in year 3. We defined incident dementia over 12 years on the basis of hospitalization records, prescription for dementia medication, or 1.5-SD decline in race-stratified global cognition score. We assessed dementia risk associated with OI score (by tertile) using Cox proportional hazards models. All analyses were stratified by race.Results: Poorer OI in older adults without dementia was associated with increased risk of dementia. After adjustment for demographics, medical comorbidities, and lifestyle characteristics, white participants in the poor or moderate OI tertile had greater risk of dementia (adjusted hazard ratio [HR] 3.34, 95% confidence interval [CI] 2.45-4.54; and HR 1.84, 95% CI 1.33-2.54, respectively) compared to those in the good tertile of function. Among blacks, worse OI was associated with an increased risk of dementia, but the magnitude of the effect was weaker (p for interaction 5 0.04) for the poor OI tertile (adjusted HR 2.03, 95% CI 1.44-2.84) and for the moderate tertile (adjusted HR 1.42, 95% CI 0.97-2.10). There was no interaction between OI and APOE e4 and risk of dementia.Conclusions: While the magnitude of the association was stronger in whites, we found that poor OI was associated with increased risk of dementia among both black and white older adults. Olfactory testing may be a simple, inexpensive, and highly sensitive method of identifying older adults at risk for developing dementia, particularly when combined with other early markers.

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Section: Resultsmentioning

confidence: 99%

Olfaction and risk of dementia in a biracial cohort of older adults

et al. 2017

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“…Odor identification testing may not give accurate results in the presence of significant nasal disease including active upper respiratory infection, and currently active smokers. Odor identification deficits can occur in individuals with several subtypes of dementia, including AD, Lewy body dementia, and possibly vascular dementia, as well as Parkinson's disease . Odor identification test performance declines with age in the general population, particularly after the 7th decade of life, and women score 3‐5% better than men on average .…”

Section: Discussionmentioning

confidence: 99%

Intact global cognitive and olfactory ability predicts lack of transition to dementia

Devanand

Lee

Luchsinger

et al. 2020

Alzheimer's & Dementia

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Introduction:Odor identification deficits characterize Alzheimer's disease and other dementias. We examined if intact performance on brief cognitive and odor identification tests predicts lack of transition to dementia. Methods:In an urban community, 1037 older adults without dementia completed the 40-item University of Pennsylvania Smell Identification Test, which includes the 12item Brief Smell Identification Test (B-SIT). Data from 749 participants followed up for 4 years were analyzed. Results: In covariate-adjusted survival analyses, impairment on the Blessed Orientation Memory Concentration Test and B-SIT each predicted dementia (n = 109), primarily Alzheimer's disease (n = 101). Among participants with intact olfactory (B-SIT ≥ 11/12 correct) and cognitive (Blessed Orientation Memory Concentration Test ≤ 5/28 incorrect) ability, 3.4% (4/117) transitioned to dementia during follow-up with no transitions in the 70-75 and 81-83 years age group quartiles.Discussion: Odor identification testing adds value to global cognitive testing, and together can identify individuals who rarely transition to dementia, thereby avoiding unnecessary diagnostic investigation.

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“…Beyond aiding in earlier diagnosis of dementia by alerting physicians to consider other factors that may affect disease development, olfactory testing may help distinguish clinically between different dementia subtypes. Cross‐sectional studies have shown associations between olfactory dysfunction and vascular dementia and frontotemporal dementia . Prior studies suggest that different types of olfactory disability (e.g., odor identification, odor discrimination, odor threshold) may be associated with different forms of dementia .…”

Section: Discussionmentioning

confidence: 99%

Olfactory Dysfunction Predicts Subsequent Dementia in Older U.S. Adults

Adams

Kern

Wroblewski

et al. 2017

J American Geriatrics Society

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Objectives To investigate the relationship between olfactory dysfunction and subsequent diagnosis of dementia. Design Longitudinal study of a population representative of U.S. older adults. Setting Home interviews (National Social Life, Health, and Aging Project). Participants Men and women aged 57 to 85 (N = 2,906). Measurements Objective odor identification ability was measured at baseline using a validated five‐item test. Five years later, the respondent, or a proxy if the respondent was too sick to interview or had died, reported physician diagnosis of dementia. The association between baseline olfactory dysfunction and an interval dementia diagnosis was tested using multivariate logistic regression, controlling for age, sex, race and ethnicity, education, comorbidities (modified Charlson Comorbidity Index), and cognition at baseline (Short Portable Mental Status Questionnaire). Results Older adults with olfactory dysfunction had more than twice the odds of having developed dementia 5 years later (odds ratio = 2.13, 95% confidence interval = 1.32–3.43), controlling for the above covariates. Having more odor identification errors was associated with greater probability of an interval dementia diagnosis (P = .04, 1‐degree of freedom linear‐trend test). Conclusion We show for the first time in a nationally representative sample that home‐dwelling older adults with normal cognition and difficulty identifying odors face higher odds of being diagnosed with dementia 5 years later, independent of other significant risk factors. This validated five‐item odor identification test is an efficient, low‐cost component of the physical examination that can provide useful information while assessing individuals’ risk of dementia. Use of such testing may provide an opportunity for early interventions to reduce the attendant morbidity and public health burden of dementia.

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Olfactory dysfunction in dementia

Cited by 81 publications

References 59 publications

Olfaction and risk of dementia in a biracial cohort of older adults

Olfaction and risk of dementia in a biracial cohort of older adults

Intact global cognitive and olfactory ability predicts lack of transition to dementia

Olfactory Dysfunction Predicts Subsequent Dementia in Older U.S. Adults

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