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Chao LL. Olfactory and cognitive decrements in 1991 Gulf War veterans with gulf war illness/chronic multisymptom illness. Environ Health 2024; 23:14. [PMID: 38291474 PMCID: PMC10825982 DOI: 10.1186/s12940-024-01058-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 01/26/2024] [Indexed: 02/01/2024]
Abstract
BACKGROUND Gulf War illness (GWI)/Chronic Multisymptom Illness (CMI) is a disorder related to military service in the 1991 Gulf War (GW). Prominent symptoms of GWI/CMI include fatigue, pain, and cognitive dysfunction. Although anosmia is not a typical GWI/CMI symptom, anecdotally some GW veterans have reported losing their sense smell shortly after the war. Because olfactory deficit is a prodromal symptom of neurodegenerative diseases like Parkinson's and Alzheimer's disease, and because we previously reported suggestive evidence that deployed GW veterans may be at increased risk for Mild Cognitive Impairment (MCI) and dementia, the current study examined the relationship between olfactory and cognitive function in deployed GW veterans. METHODS Eighty deployed GW veterans (mean age: 59.9 ±7.0; 4 female) were tested remotely with the University of Pennsylvania Smell Identification Test (UPSIT) and the Montreal Cognitive Assessment (MoCA). Veterans also completed self-report questionnaires about their health and deployment-related exposures and experiences. UPSIT and MoCA data from healthy control (HC) participants from the Parkinson's Progression Markers Initiative (PPMI) study were downloaded for comparison. RESULTS GW veterans had a mean UPSIT score of 27.8 ± 6.3 (range 9-37) and a mean MoCA score of 25.3 ± 2.8 (range 19-30). According to age- and sex-specific normative data, 31% of GW veterans (vs. 8% PPMI HCs) had UPSIT scores below the 10th percentile. Nearly half (45%) of GW veterans (vs. 8% PPMI HCs) had MoCA scores below the cut-off for identifying MCI. Among GW veterans, but not PPMI HCs, there was a positive correlation between UPSIT and MoCA scores (Spearman's ρ = 0.39, p < 0.001). There were no significant differences in UPSIT or MoCA scores between GW veterans with and without history of COVID or between those with and without Kansas GWI exclusionary conditions. CONCLUSIONS We found evidence of olfactory and cognitive deficits and a significant correlation between UPSIT and MoCA scores in a cohort of 80 deployed GW veterans, 99% of whom had CMI. Because impaired olfactory function has been associated with increased risk for MCI and dementia, it may be prudent to screen aging, deployed GW veterans with smell identification tests so that hypo- and anosmic veterans can be followed longitudinally and offered targeted neuroprotective therapies as they become available.
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Affiliation(s)
- Linda L Chao
- Departments of Radiology & Biomedical Imaging and Psychiatry & Behavioral Science, University of Calfiornia, 505 Parnassus Avenue, San Francisco, CA, 94143, USA.
- San Francisco Veterans Affairs Health Care System, 4150 Clement Street, San Francisco, CA, 94121, USA.
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2
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Pacyna RR, Han SD, Wroblewski KE, McClintock MK, Pinto JM. Rapid olfactory decline during aging predicts dementia and GMV loss in AD brain regions. Alzheimers Dement 2022; 19:1479-1490. [PMID: 35899859 DOI: 10.1002/alz.12717] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 02/23/2022] [Accepted: 05/18/2022] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Longitudinal multivariable analyses are needed to determine if the rate of olfactory decline during normal cognition predicts subsequent Alzheimer's disease (AD) diagnoses and brain dysmorphology. METHODS Older adults (n = 515) were assessed annually for odor identification, cognitive function and dementia clinical diagnosis (max follow-up 18 years). Regional gray matter volumes (GMV) were quantified (3T MRI) in a cross-sectional subsample (n = 121). Regression models were adjusted for APOE-ε4 genotype, dementia risk factors and demographics. RESULTS Faster olfactory decline during periods of normal cognition predicted higher incidence of subsequent MCI or dementia (OR 1.89, 95% CI: 1.26, 2.90, p < 0.01; comparable to carrying an APOE-ε4 allele) and smaller GMV in AD and olfactory regions (β = -0.11, 95% CI -0.21, -0.00). DISCUSSION Rapid olfactory decline during normal cognition, using repeated olfactory measurement, predicted subsequent cognitive impairment, dementia, and smaller GMVs, highlighting its potential as a simple biomarker for early AD detection. HIGHLIGHTS Rate of olfactory decline was calculated from olfactory testing over ≥3 time points. Rapid olfactory decline predicted impaired cognition and higher risk of dementia. Neurodegeneration on 3T magnetic resonance imaging was identical in those with olfactory decline and Alzheimer's disease.
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Affiliation(s)
- Rachel R Pacyna
- Pritzker, School of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - S Duke Han
- Departments of Family Medicine, Neurology, Psychology, and Gerontology, University of Southern California, Alhambra, California, USA
| | - Kristen E Wroblewski
- Department of Public Health Sciences, The University of Chicago, Chicago, Illinois, USA
| | | | - Jayant M Pinto
- Department of Surgery, and Section of Otolaryngology-Head and Neck Surgery, The University of Chicago, Chicago, Illinois, USA
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3
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Pang NYL, Song HJJMD, Tan BKJ, Tan JX, Chen ASR, See A, Xu S, Charn TC, Teo NWY. Association of Olfactory Impairment With All-Cause Mortality: A Systematic Review and Meta-analysis. JAMA Otolaryngol Head Neck Surg 2022; 148:436-445. [PMID: 35389456 PMCID: PMC8990356 DOI: 10.1001/jamaoto.2022.0263] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Importance Olfactory impairment is highly prevalent and associated with multiple comorbidities, including neurodegenerative, cardiovascular, nutritional, and immune disorders. However, epidemiologic associations between olfactory impairment and mortality are discordant. Objective To systematically clarify the epidemiologic associations between olfactory impairment and mortality. Data Sources The PubMed, Embase, and Cochrane Library databases were searched from inception to August 13, 2021. Study Selection Two blinded reviewers selected observational studies published as full-length, English-language articles in peer-reviewed journals that reported the presence or severity of chronic olfactory impairment, whether objectively measured or self-reported, in association with any mortality estimate, among adults aged 18 years or older. Data Extraction and Synthesis Two reviewers independently extracted data, evaluated study bias using the Newcastle-Ottawa Scale, and appraised the quality of the evidence using the Grading of Recommendations Assessment, Development and Evaluation framework, following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines and a PROSPERO-registered protocol. Maximally adjusted estimates were pooled using mixed-effects models, heterogeneity was measured using I2 statistics, sources of heterogeneity were investigated using meta-regression and subgroup meta-analyses, and publication bias was qualitatively and quantitatively assessed. Main Outcomes and Measures Hazard ratios for all-cause mortality. Results One retrospective cohort study and 10 prospective cohort studies (with a total of 21 601 participants) from 1088 nonduplicated records were included. Ten studies had a low risk of bias, whereas 1 study had a moderate risk; exclusion of the latter did not alter conclusions. Nine studies were included in the meta-analysis. Olfactory loss was associated with a significantly higher pooled hazard of all-cause mortality (hazard ratio, 1.52; 95% CI, 1.28-1.80; I2 = 82%). Meta-regression sufficiently explained heterogeneity, with longer mean follow-up duration weakening the pooled association, accounting for 91.3% of heterogeneity. Self-reported and objective effect sizes were similar. Associations were robust to trim-and-fill adjustment and the Egger test for publication bias. The overall quality of evidence was moderate. Conclusions and Relevance The findings of this systematic review and meta-analysis suggest that olfactory impairment is associated with all-cause mortality and may be a marker of general health and biological aging. Further research is required to establish the underlying mechanisms and the scope for interventions.
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Affiliation(s)
| | | | | | - Jun Xiang Tan
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ashley Si Ru Chen
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Anna See
- Department of Otorhinolaryngology-Head & Neck Surgery, Singapore General Hospital, Singapore.,Department of Otorhinolaryngology-Head & Neck Surgery, Sengkang General Hospital, Singapore.,Surgery Academic Clinical Program, SingHealth, Singapore
| | - Shuhui Xu
- Department of Otorhinolaryngology-Head & Neck Surgery, Singapore General Hospital, Singapore.,Surgery Academic Clinical Program, SingHealth, Singapore
| | - Tze Choong Charn
- Department of Otorhinolaryngology-Head & Neck Surgery, Sengkang General Hospital, Singapore.,Surgery Academic Clinical Program, SingHealth, Singapore
| | - Neville Wei Yang Teo
- Department of Otorhinolaryngology-Head & Neck Surgery, Singapore General Hospital, Singapore.,Surgery Academic Clinical Program, SingHealth, Singapore
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Lessard-Beaudoin M, M Gonzalez L, AlOtaibi M, Chouinard-Watkins R, Plourde M, Calon F, Graham RK. Diet enriched in omega-3 fatty acids alleviates olfactory system deficits in APOE4 transgenic mice. Eur J Neurosci 2021; 54:7092-7108. [PMID: 34549475 DOI: 10.1111/ejn.15472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 11/30/2022]
Abstract
Olfactory dysfunction is observed in several neurological disorders including Mild Cognitive Impairment (MCI) and Alzheimer disease (AD). These deficits occur early and correlate with global cognitive performance, depression and degeneration of olfactory regions in the brain. Despite extensive human studies, there has been little characterization of the olfactory system in models of AD. In order to determine if olfactory structural and/or molecular phenotypes are observed in a model expressing a genetic risk factor for AD, we assessed the olfactory bulb (OB) in APOE4 transgenic mice. A significant decrease in OB weight was observed at 12 months of age in APOE4 mice concurrent with inflammation and decreased NeuN expression. In order to determine if a diet rich in omega-3s may alleviate the olfactory system phenotypes observed, we assessed WT and APOE4 mice on a docosahexaenoic acid (DHA) diet. APOE4 mice on a DHA diet did not present with atrophy of the OB, and the alterations in NeuN and IBA-1 expression were alleviated. Furthermore, alterations in caspase mRNA and protein expression in the APOE4 OB were not observed with a DHA diet. Similar to the human AD condition, OB atrophy is an early phenotype in the APOE4 mice and concurrent with inflammation. These data support a link between the structural olfactory brain region atrophy and the olfactory dysfunction observed in AD and suggest that inflammation and cell death pathways may contribute to the olfactory deficits observed. Furthermore, the results suggest that diets enriched in DHA may provide benefit to APOE4 allele carriers.
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Affiliation(s)
- Melissa Lessard-Beaudoin
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Laura M Gonzalez
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Majed AlOtaibi
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Quebec, Canada.,Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Raphaël Chouinard-Watkins
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Melanie Plourde
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Frederic Calon
- Faculty of Pharmacy, Centre de Recherche du CHU de Québec, Université Laval, Quebec City, Quebec, Canada
| | - Rona K Graham
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Quebec, Canada
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Olofsson JK. Olfaction and Aging: A Review of the Current State of Research and Future Directions. Iperception 2021; 12:20416695211020331. [PMID: 34249327 PMCID: PMC8239976 DOI: 10.1177/20416695211020331] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/21/2021] [Indexed: 11/16/2022] Open
Abstract
Olfaction, the sense of smell, is characterized by a notable age-dependency such that aging individuals are more likely to have poor olfactory abilities. These impairments are considered to be mostly irreversible and as having potentially profound effects on quality of life and food behavior, as well as constituting warning signs of mortality, cognitive dysfunction, and dementia. Here, we review the current state of research on aging and olfaction, focusing on five topics which we regard to be of particular relevance for the field: nutrition and health, cognition and dementia, mortality, environment and genetics, and training-based enhancement. Under each of these headlines, we provide a state-of-the-art overview and discuss gaps in our knowledge which might be filled by further research. Understanding how olfactory abilities are diminished in aging, and how they may be alleviated or recovered, involves a set of challenging tasks for researchers in the years to come.
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Affiliation(s)
- Jonas K. Olofsson
- Gösta Ekman Laboratory, Stockholm University, Stockholm, Sweden; Department of Psychology, Stockholm University, Stockholm, Sweden
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The Association Between Olfactory Function and Cognition in Aging African American and Caucasian Men With HIV: A Pilot Study. J Assoc Nurses AIDS Care 2020; 30:e144-e155. [PMID: 31259847 DOI: 10.1097/jnc.0000000000000086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Older adults and people living with HIV have been shown to experience disproportionately more olfactory dysfunction. Some neurological studies suggest that olfactory dysfunction may be a precursor to cognitive dysfunction. The purpose of our study was to determine whether olfactory dysfunction was predictive of cognition. In our cross-sectional study, 51 African American and Caucasian men living with HIV (ages ≥ 40 years) were administered a cognitive performance battery and two objective olfactory measures (the University of Pennsylvania Smell Identification Test and the Smell Threshold Test). The strongest cognitive associations to the University of Pennsylvania Smell Identification Test performance were found in the Hopkins Verbal Learning Test, a measure of verbal learning and verbal memory. These findings were consistent with previous research, demonstrating a relationship between decreased olfactory function and poorer cognitive performance. An important clinical implication from these results is the potential use of olfactory dysfunction as a prodromal biomarker for HIV-associated neurocognitive disorder.
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Interaction Between Odor Identification Deficit and APOE4 Predicts 6-Year Cognitive Decline in Elderly Individuals. Behav Genet 2019; 50:3-13. [PMID: 31760549 PMCID: PMC6941999 DOI: 10.1007/s10519-019-09980-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 11/12/2019] [Indexed: 02/08/2023]
Abstract
Olfactory identification impairment might indicate future cognitive decline in elderly individuals. An unresolved question is to what extent this effect is dependent on the ApoE-ε4, a genotype associated with risk of Alzheimer’s Disease (AD). Given the current concern about reproducibility in empirical research, we assessed this issue in a large sample (n = 1637) of older adults (60 – 96 years) from the population-based longitudinal Swedish National Study on Aging and Care in Kungsholmen (SNAC-K). A hierarchical regression analysis was carried out to determine if a low score on an odor identification test, and the presence of ApoE-ε4, would predict the magnitude of a prospective 6-year change in the Mini-Mental State Examination (MMSE) after controlling for demographic, health-related, and cognitive variables. We found that overall, lower odor identification performance was predictive of cognitive decline, and, as hypothesized, we found that the effect was most pronounced among ApoE-ε4 carriers. Our results from this high-powered sample suggest that in elderly carriers of the ApoE-ε4 allele, odor identification impairment provides an indication of future cognitive decline, which has relevance for the prognosis of AD.
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8
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Bower ES, Szajer J, Murphy C. Effect of Worry Level on Recall Memory for Odors in ApoE-ε4 Carriers and Non-Carriers. J Int Neuropsychol Soc 2019; 25:546-556. [PMID: 30987686 PMCID: PMC6534430 DOI: 10.1017/s1355617719000158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Increased levels of worry, age, and presence of the apolipoprotein-E (ApoE)-ε4 allele are associated with the risk of developing cognitive declines and Alzheimer's disease (AD). Odor memory performance has been shown to vary as a function of age and ApoE genotype, and odor memory tests are sensitive to preclinical AD. Worry is known to influence verbal memory; however, its effects on odor memory are unknown. This study aimed to assess the relationships between worry, age, and ε4 status on odor memory. METHOD Worry was evaluated for young (n = 53) and older (n = 45) adults using the Penn State Worry Questionnaire. Odor memory was assessed using the California Odor Learning Test, an olfactory analogue to the California Verbal Learning Test. RESULTS A significant main effect of worry on long-delay free recall was found, such that increasing worry was associated with better recall across age and ε4 status. A significant interaction effect between ε4 status and worry on both short-and long-delay cued recall was found, such that across age, higher worry was associated with increased cued recall scores among ε4-negative adults, and decreased scores among ε4-positive adults. CONCLUSIONS Findings demonstrated that worry influences odor memory and exerts a particular effect on cued recall among ε4 carriers who are at a greater risk of developing AD. Worry is a modifiable predictor of cognitive decline and risk of dementia in aging. Future studies on the effects of treatments aimed at reducing worry (e.g., cognitive behavioral therapies for anxiety) on changes in cognitive functioning are warranted.
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Affiliation(s)
- Emily S Bower
- Department of Psychology,San Diego State University,San Diego, California 92182,USA
| | - Jacquelyn Szajer
- SDSU/UCSD Joint Doctoral Program in Clinical Psychology,San Diego, California 92120,USA
| | - Claire Murphy
- Department of Psychology,San Diego State University,San Diego, California 92182,USA
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Marseglia A, Dahl Aslan AK, Fratiglioni L, Santoni G, Pedersen NL, Xu W. Cognitive Trajectories of Older Adults With Prediabetes and Diabetes: A Population-Based Cohort Study. J Gerontol A Biol Sci Med Sci 2019. [PMID: 28633303 DOI: 10.1093/gerona/glx112] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Background Diabetes has been linked to dementia risk; however, the cognitive trajectories in older adults with diabetes remain unclear. We aimed to investigate the effect of prediabetes and diabetes on cognitive trajectories among cognitively intact older adults in a long-term follow-up study. Methods Within the Swedish Adoption/Twin Study of Aging, 793 cognitively intact older adults aged ≥50 were identified at baseline and followed for up to 23 years. Based on standardized scores from 11 cognitive tests, administered at baseline and up to seven follow-ups, four cognitive domains (verbal abilities, spatial/fluid, memory, perceptual speed) were identified by principal-component analysis. Prediabetes was defined according to blood glucose levels in diabetes-free participants. Diabetes was ascertained based on self-report, hypoglycemic medication use and blood glucose levels. Data were analyzed with linear mixed-effect models adjusting for potential confounders. Results At baseline, 68 participants (8.6%) had prediabetes and 45 (5.7%) had diabetes. Compared to diabetes-free individuals, people with diabetes had a steeper decline over time in perceptual speed and verbal abilities. The annual declines in these domains were greater than the annual decline in memory. Prediabetes was associated with lower performance in memory in middle-age, but also associated with a less steep memory decline over the follow-up. Conclusions Diabetes is associated with a faster decline in perceptual speed and verbal abilities, while prediabetes is associated with lower memory performance in middle-age. However, the detrimental effects of hyperglycemia seem to not affect memory over time.
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Affiliation(s)
- Anna Marseglia
- Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University, Sweden
| | - Anna K Dahl Aslan
- Institute of Gerontology, School of Health and Welfare, Jönköping University, Sweden.,Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Laura Fratiglioni
- Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University, Sweden.,Stockholm Gerontology Research Center, Sweden
| | - Giola Santoni
- Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University, Sweden
| | - Nancy L Pedersen
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.,Department of Psychology, University of Southern California, Los Angeles, California
| | - Weili Xu
- Aging Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University, Sweden.,Department of Epidemiology and Biostatistics, School of Public Health, Tianjin Medical University, China
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Dintica CS, Marseglia A, Rizzuto D, Wang R, Seubert J, Arfanakis K, Bennett DA, Xu W. Impaired olfaction is associated with cognitive decline and neurodegeneration in the brain. Neurology 2019; 92:e700-e709. [PMID: 30651382 PMCID: PMC6382360 DOI: 10.1212/wnl.0000000000006919] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 12/14/2018] [Indexed: 11/28/2022] Open
Abstract
Objective We aimed to examine whether impaired olfaction is associated with cognitive decline and indicators of neurodegeneration in the brain of dementia-free older adults. Methods Within 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. Results At 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. Conclusion Impaired olfaction predicts faster cognitive decline and might indicate neurodegeneration in the brain among dementia-free older adults.
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Affiliation(s)
- Christina S Dintica
- From the Aging Research Center (C.S.D., A.M., D.R., R.W., J.S., W.X.), Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University; Department of Clinical Neuroscience (J.S.), Psychology Division, Karolinska Institutet, Stockholm, Sweden; Department of Biomedical Engineering (K.A.), Illinois Institute of Technology, Chicago; Rush Alzheimer's Disease Center (K.A., D.A.B.), and Department of Neurological Sciences (D.A.B.), Rush University Medical Center, Chicago, IL; and Department of Epidemiology and Biostatistics (W.X.), School of Public Health, Tianjin Medical University, China.
| | - Anna Marseglia
- From the Aging Research Center (C.S.D., A.M., D.R., R.W., J.S., W.X.), Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University; Department of Clinical Neuroscience (J.S.), Psychology Division, Karolinska Institutet, Stockholm, Sweden; Department of Biomedical Engineering (K.A.), Illinois Institute of Technology, Chicago; Rush Alzheimer's Disease Center (K.A., D.A.B.), and Department of Neurological Sciences (D.A.B.), Rush University Medical Center, Chicago, IL; and Department of Epidemiology and Biostatistics (W.X.), School of Public Health, Tianjin Medical University, China
| | - Debora Rizzuto
- From the Aging Research Center (C.S.D., A.M., D.R., R.W., J.S., W.X.), Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University; Department of Clinical Neuroscience (J.S.), Psychology Division, Karolinska Institutet, Stockholm, Sweden; Department of Biomedical Engineering (K.A.), Illinois Institute of Technology, Chicago; Rush Alzheimer's Disease Center (K.A., D.A.B.), and Department of Neurological Sciences (D.A.B.), Rush University Medical Center, Chicago, IL; and Department of Epidemiology and Biostatistics (W.X.), School of Public Health, Tianjin Medical University, China
| | - Rui Wang
- From the Aging Research Center (C.S.D., A.M., D.R., R.W., J.S., W.X.), Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University; Department of Clinical Neuroscience (J.S.), Psychology Division, Karolinska Institutet, Stockholm, Sweden; Department of Biomedical Engineering (K.A.), Illinois Institute of Technology, Chicago; Rush Alzheimer's Disease Center (K.A., D.A.B.), and Department of Neurological Sciences (D.A.B.), Rush University Medical Center, Chicago, IL; and Department of Epidemiology and Biostatistics (W.X.), School of Public Health, Tianjin Medical University, China
| | - Janina Seubert
- From the Aging Research Center (C.S.D., A.M., D.R., R.W., J.S., W.X.), Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University; Department of Clinical Neuroscience (J.S.), Psychology Division, Karolinska Institutet, Stockholm, Sweden; Department of Biomedical Engineering (K.A.), Illinois Institute of Technology, Chicago; Rush Alzheimer's Disease Center (K.A., D.A.B.), and Department of Neurological Sciences (D.A.B.), Rush University Medical Center, Chicago, IL; and Department of Epidemiology and Biostatistics (W.X.), School of Public Health, Tianjin Medical University, China
| | - Konstantinos Arfanakis
- From the Aging Research Center (C.S.D., A.M., D.R., R.W., J.S., W.X.), Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University; Department of Clinical Neuroscience (J.S.), Psychology Division, Karolinska Institutet, Stockholm, Sweden; Department of Biomedical Engineering (K.A.), Illinois Institute of Technology, Chicago; Rush Alzheimer's Disease Center (K.A., D.A.B.), and Department of Neurological Sciences (D.A.B.), Rush University Medical Center, Chicago, IL; and Department of Epidemiology and Biostatistics (W.X.), School of Public Health, Tianjin Medical University, China
| | - David A Bennett
- From the Aging Research Center (C.S.D., A.M., D.R., R.W., J.S., W.X.), Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University; Department of Clinical Neuroscience (J.S.), Psychology Division, Karolinska Institutet, Stockholm, Sweden; Department of Biomedical Engineering (K.A.), Illinois Institute of Technology, Chicago; Rush Alzheimer's Disease Center (K.A., D.A.B.), and Department of Neurological Sciences (D.A.B.), Rush University Medical Center, Chicago, IL; and Department of Epidemiology and Biostatistics (W.X.), School of Public Health, Tianjin Medical University, China
| | - Weili Xu
- From the Aging Research Center (C.S.D., A.M., D.R., R.W., J.S., W.X.), Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Stockholm University; Department of Clinical Neuroscience (J.S.), Psychology Division, Karolinska Institutet, Stockholm, Sweden; Department of Biomedical Engineering (K.A.), Illinois Institute of Technology, Chicago; Rush Alzheimer's Disease Center (K.A., D.A.B.), and Department of Neurological Sciences (D.A.B.), Rush University Medical Center, Chicago, IL; and Department of Epidemiology and Biostatistics (W.X.), School of Public Health, Tianjin Medical University, China.
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Stewart CC, Boyle PA, James BD, Yu L, Han SD, Bennett DA. Associations of APOE ε4 With Health and Financial Literacy Among Community-Based Older Adults Without Dementia. J Gerontol B Psychol Sci Soc Sci 2018; 73:778-786. [PMID: 27174891 PMCID: PMC6283314 DOI: 10.1093/geronb/gbw054] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 04/21/2016] [Indexed: 01/10/2023] Open
Abstract
Objectives Older adults often exhibit low health and financial literacy, but the reasons why remain unclear. One possibility is that those older adults at high risk for developing dementia demonstrate low literacy even in the absence of marked cognitive impairment. We therefore examined associations of health and financial literacy with the APOE ε4 allele, the chief genetic risk factor for Alzheimer's disease, among older adults without dementia. Method Participants were 487 older adults without dementia enrolled in the Rush Memory and Aging Project (mean age = 83, mean years of education = 15, 77% female, 91% non-Hispanic White). Participants underwent APOE genotyping and assessments of cognition, health literacy, and financial literacy. Health and financial literacy scores were also averaged into a total literacy score. Results ε4 was associated with lower total and health literacy, with a trend toward an association with lower financial literacy, after adjustment for age, sex, and education. Associations of ε4 with lower total and health literacy persisted after further adjustment for global cognitive function and 5 specific cognitive domains. Discussion ε4 affects literacy even in the absence of clinical dementia and does so relatively independent of performance on traditional cognitive tests.
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Affiliation(s)
- Christopher C Stewart
- Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois
| | - Patricia A Boyle
- Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, Illinois
| | - Bryan D James
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, Illinois
- Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois
| | - Lei Yu
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, Illinois
- Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois
| | - S Duke Han
- Departments of Family Medicine, Neurology, and Psychology, University of Southern California, Los Angeles
| | - David A Bennett
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, Illinois
- Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois
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Goette WF, Werry AE, Schmitt AL. The relationship between smell identification and neuropsychological domains: Results from a sample of community-dwelling adults suspected of dementia. J Clin Exp Neuropsychol 2017; 40:595-605. [PMID: 29202669 DOI: 10.1080/13803395.2017.1399985] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE This study aimed to test the theoretical relationships between smell identification and cognitive tasks based on existing neuroimaging and anatomical findings. METHOD Utilizing data collected from a memory assessment clinic, theory-derived mediation and moderation models were tested. The sample used in this study consisted of 103 (39 male, 64 female) individuals referred for memory assessments. The sample's mean education was 12.4 years (SD = 3.2), and the mean age of the sample was 77.2 years (SD = 6.3). RESULTS The University of Pennsylvania Smell Identification Test (UPSIT) was a significant, partial mediator of the relationship between the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Immediate and Delayed Memory indexes. Olfactory identification did not mediate list learning and retrieval; however, olfactory identification was a significant partial mediator of the relationship between story encoding and later memory retrieval of the story. Olfactory identification also fully mediated the relationship between a visuospatial construction task and its reconstruction from memory after a short delay. The relationship between processing speed and the olfactory identification was significantly mediated by semantic memory. Finally, the UPSIT moderated the relationship between a measure of premorbid ability, the Wechsler Test of Adult Reading, and current global cognitive functioning. CONCLUSIONS Our results support theoretical relationships between olfaction and neuropsychological domains. Additionally, our results suggest that the UPSIT may serve as a proxy for cerebral integrity and is likely related to the duration of neurodegeneration.
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Affiliation(s)
- William F Goette
- a University of Texas at Tyler , Department of Psychology and Counseling , Tyler , TX , USA
| | - Amy E Werry
- b School of Graduate Psychology , Pacific University , Hillsboro , OR , USA
| | - Andrew L Schmitt
- a University of Texas at Tyler , Department of Psychology and Counseling , Tyler , TX , USA
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Goette W, Schmitt A, Clark A. Relationship between smell identification testing and the neuropsychological assessment of dementia in community-dwelling adults. APPLIED NEUROPSYCHOLOGY-ADULT 2017; 26:201-214. [PMID: 29182360 DOI: 10.1080/23279095.2017.1392303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The objective of this research was to investigate the relationship of the University of Pennsylvania Smell Identification Test (UPSIT) with neuropsychological tests and identify the utility of the UPSIT in detecting cognitive impairment. This research was an archival study of neuropsychological test results obtained from 70 clients (30 male/40 female) of a community-based memory clinic. The sample had an average age of 69.7 (SD = 9.7) and education of 14.6 (SD = 2.8) years. Hypotheses were tested using correlations, receiver operating characteristic (ROC) curves, and logistic regression. The UPSIT showed significant, weak to moderate correlations with neuropsychological tests. The UPSIT raw score correlated significantly with all but one cognitive ability domain. The UPSIT T-score was significantly correlated with all cognitive domains. Obtained areas under the ROC curve (AUC) for the UPSIT ranged from .60 to .87. The AUCs of the UPSIT did not differ significantly from verbal semantic fluency tests, but the Repeatable Battery for the Assessment of Neuropsychological Status Total Scale and Delayed Memory index tended to produce larger AUCs than the UPSIT. Results from step-wise logistic regressions suggest that the UPSIT raw score provides unique information beyond its relationship to age. Olfaction relates broadly to cognitive ability and may be sensitive to early symptoms of cognitive decline. Further research is needed to explore the relationships between smell identification tests and neuropsychological assessment.
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Affiliation(s)
- William Goette
- a Department of Psychology and Counseling , University of Texas at Tyler , Tyler , Texas , USA
| | - Andrew Schmitt
- a Department of Psychology and Counseling , University of Texas at Tyler , Tyler , Texas , USA
| | - Avery Clark
- a Department of Psychology and Counseling , University of Texas at Tyler , Tyler , Texas , USA
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14
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Cognitive behavioral therapy (CBT) for preventing Alzheimer's disease. Behav Brain Res 2017; 334:163-177. [PMID: 28743599 DOI: 10.1016/j.bbr.2017.07.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/15/2017] [Accepted: 07/18/2017] [Indexed: 12/13/2022]
Abstract
This review provides the rationale for implementing cognitive behavioral therapy (CBT) for the prevention of Alzheimer's disease (AD). There are known risk factors associated with the development of AD, some of which may be ameliorated with CBT. We posit that treating the risk factors of inactivity, poor diet, hyposmia and anosmia, sleep disorders and lack of regularly engaged challenging cognitive activity will modify the physiology of the brain sufficiently to avoid the accumulation of excess proteins, including amyloid beta, causal events in the development of AD. Further, the successful treatment of the listed risk factors is well within our technology to do so and, even further, it is cost effective. Also, there is considerable scientific literature to support the proposition that, if implemented by well-established practices, CBT will be effective and will be engaged by those of retirement age. That is, we present a biologically informed CBT for the prevention of the development of AD, i.e., an aspect of applied behavioral neuroscience.
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15
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Josefsson M, Larsson M, Nordin S, Adolfsson R, Olofsson J. APOE-ɛ4 effects on longitudinal decline in olfactory and non-olfactory cognitive abilities in middle-aged and old adults. Sci Rep 2017; 7:1286. [PMID: 28455505 PMCID: PMC5430873 DOI: 10.1038/s41598-017-01508-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/28/2017] [Indexed: 11/29/2022] Open
Abstract
Characterizing aging-related decline trajectories in mental abilities, and relationships of the ɛ4 allele of the Apolipoprotein gene, helps to identify individuals at high risk for dementia. However, longitudinal changes in olfactory and non-olfactory cognitive abilities have not been investigated in relation to the ɛ4 allele. In the present study, participants from a large population-based study (657 middle-aged and 556 old) were tested over 10 years on their performance on an odor identification task and three non-olfactory cognitive tasks; MMSE, episodic memory, and semantic memory. Our key finding is that in middle-aged participants, odor identification declined twice as fast for ɛ4/4 homozygotes, compared to non-carriers. However, in old participants, the ɛ4/4 homozygotes showed an impaired odor identification ability, but they declined at a similar rate as the non-carriers. Furthermore, in old participants all assessments displayed aging-related declines, but exaggerated declines in ɛ4-carriers were found only in MMSE and episodic memory assessments. In sum, we present evidence that odor identification ability starts to decline already in middle-aged, and that carriers of ɛ4/4, who are at highest risk of developing dementia, decline twice as fast. Our results may have implications for use of odor identification assessment in detection of early-stage dementia.
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Affiliation(s)
- Maria Josefsson
- Centre for Demographic and Ageing Research, Umeå University, Umeå, Sweden.
| | - Maria Larsson
- Gösta Ekman Laboratory, Department of Psychology, Stockholm University, Stockholm, Sweden
| | - Steven Nordin
- Department of Psychology, Umeå University, Umeå, Sweden
| | - Rolf Adolfsson
- Department of Clinical Sciences, Psychiatry, Umeå University Hospital, Umeå, Sweden
| | - Jonas Olofsson
- Gösta Ekman Laboratory, Department of Psychology, Stockholm University, Stockholm, Sweden.,Swedish Collegium for Advanced Study, Uppsala, Sweden
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16
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Ekström I, Sjölund S, Nordin S, Nordin Adolfsson A, Adolfsson R, Nilsson LG, Larsson M, Olofsson JK. Smell Loss Predicts Mortality Risk Regardless of Dementia Conversion. J Am Geriatr Soc 2017; 65:1238-1243. [PMID: 28326534 DOI: 10.1111/jgs.14770] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To determine whether dementia could explain the association between poor olfactory performance and mortality risk within a decade-long follow-up period. DESIGN Prospective cohort study. SETTING Betula Study, Umeå, Sweden. PARTICIPANTS A population-based sample of adult participants without dementia at baseline aged 40 to 90 (N = 1,774). MEASUREMENTS Olfactory performance using the Scandinavian Odor-Identification Test (SOIT) and self-reported olfactory function; several social, cognitive, and medical risk factors at baseline; and incident dementia during the following decade. RESULTS Within the 10-year follow-up, 411 of 1,774 (23.2%) participants had died. In a Cox model, the association between higher SOIT score and lower mortality was significant (hazard ratio (HR) = 0.74 per point interval, 95% confidence interval (CI) = 0.71-0.77, P < .001). The effect was attenuated, but remained significant, after controlling for age, sex, education, and health-related and cognitive variables (HR = 0.92, 95% CI = 0.87-0.97, P = .001). The association between SOIT score and mortality was retained after controlling for dementia conversion before death (HR = 0.92, 95% CI = 0.87-0.97, P = .001). Similar results were obtained for self-reported olfactory dysfunction. CONCLUSION Poor odor identification and poor self-reported olfactory function are associated with greater likelihood of future mortality. Dementia does not attenuate the association between olfactory loss and mortality, suggesting that olfactory loss might mark deteriorating health, irrespective of dementia.
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Affiliation(s)
- Ingrid Ekström
- Gösta Ekman Laboratory, Psychology Department, Stockholm University, Stockholm, Sweden
| | - Sara Sjölund
- Gösta Ekman Laboratory, Psychology Department, Stockholm University, Stockholm, Sweden
| | - Steven Nordin
- Department of Psychology, Umeå University, Umeå, Sweden
| | | | - Rolf Adolfsson
- Department of Clinical Sciences, Umeå University, Umeå, Sweden
| | - Lars-Göran Nilsson
- Gösta Ekman Laboratory, Psychology Department, Stockholm University, Stockholm, Sweden
| | - Maria Larsson
- Gösta Ekman Laboratory, Psychology Department, Stockholm University, Stockholm, Sweden
| | - Jonas K Olofsson
- Gösta Ekman Laboratory, Psychology Department, Stockholm University, Stockholm, Sweden.,Swedish Collegium for Advanced Study, Uppsala, Sweden
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Abstract
OBJECTIVES Discrepant findings of age-related effects between cross-sectional and longitudinal studies on executive function (EF) have been described across different studies. The aim of the present study was to examine longitudinal age effects on inhibition and switching, two key subfunctions of EF, calculated from results on the Color Word Interference Test (CWIT). METHODS One hundred twenty-three healthy aging individuals (average age 61.4 years; 67% women) performed the CWIT up to three times, over a period of more than 6 years. Measures of inhibition, switching, and combined inhibition and switching were analyzed. A longitudinal linear mixed effects models analysis was run including basic CWIT conditions, and measures of processing speed, retest effect, gender, education, and age as predictors. RESULTS After taking all predictors into account, age added significantly to the predictive value of the longitudinal models of (i) inhibition, (ii) switching, and (iii) combined inhibition and switching. The basic CWIT conditions and the processing speed measure added to the predictive value of the models, while retest effect, gender, and education did not. CONCLUSIONS The present study on middle-aged to older individuals showed age-related decline in inhibition and switching abilities. This decline was retained even when basic CWIT conditions, processing speed, attrition, gender, and education were controlled. (JINS, 2017, 23, 90-97).
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Olofsson JK, Josefsson M, Ekström I, Wilson D, Nyberg L, Nordin S, Nordin Adolfsson A, Adolfsson R, Nilsson LG, Larsson M. Long-term episodic memory decline is associated with olfactory deficits only in carriers of ApoE-є4. Neuropsychologia 2016; 85:1-9. [DOI: 10.1016/j.neuropsychologia.2016.03.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 02/06/2023]
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19
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Reynolds CA, Gatz M, Christensen K, Christiansen L, Dahl Aslan AK, Kaprio J, Korhonen T, Kremen WS, Krueger R, McGue M, Neiderhiser JM, Pedersen NL. Gene-Environment Interplay in Physical, Psychological, and Cognitive Domains in Mid to Late Adulthood: Is APOE a Variability Gene? Behav Genet 2016; 46:4-19. [PMID: 26538244 PMCID: PMC4858319 DOI: 10.1007/s10519-015-9761-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 10/14/2015] [Indexed: 10/22/2022]
Abstract
Despite emerging interest in gene-environment interaction (GxE) effects, there is a dearth of studies evaluating its potential relevance apart from specific hypothesized environments and biometrical variance trends. Using a monozygotic within-pair approach, we evaluated evidence of G×E for body mass index (BMI), depressive symptoms, and cognition (verbal, spatial, attention, working memory, perceptual speed) in twin studies from four countries. We also evaluated whether APOE is a 'variability gene' across these measures and whether it partly represents the 'G' in G×E effects. In all three domains, G×E effects were pervasive across country and gender, with small-to-moderate effects. Age-cohort trends were generally stable for BMI and depressive symptoms; however, they were variable-with both increasing and decreasing age-cohort trends-for different cognitive measures. Results also suggested that APOE may represent a 'variability gene' for depressive symptoms and spatial reasoning, but not for BMI or other cognitive measures. Hence, additional genes are salient beyond APOE.
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Affiliation(s)
- Chandra A Reynolds
- Department of Psychology, University of California Riverside, 900 University Ave., Riverside, CA, 92521, USA.
| | - Margaret Gatz
- Department of Psychology, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, 17177, Stockholm, Sweden
| | - Kaare Christensen
- Epidemiology, Biostatistics and Bio-demography, Institute of Public Health, University of Southern Denmark, 5000, Odense C, Denmark
- Department of Clinical Genetics and Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Odense, Denmark
| | - Lene Christiansen
- Epidemiology, Biostatistics and Bio-demography, Institute of Public Health, University of Southern Denmark, 5000, Odense C, Denmark
| | - Anna K Dahl Aslan
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, 17177, Stockholm, Sweden
- Institute of Gerontology, School of Health and Welfare, Jönköping University, Jönköping, Sweden
| | - Jaakko Kaprio
- Department of Public Health & Institute for Molecular Medicine FIMM, University of Helsinki, 00014, Helsinki, Finland
| | - Tellervo Korhonen
- Department of Public Health, University of Helsinki, 00014, Helsinki, Finland
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, 70211, Kuopio, Finland
| | - William S Kremen
- Department of Psychiatry, University of California San Diego, La Jolla, CA, 92093, USA
| | - Robert Krueger
- Department of Psychology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Matt McGue
- Epidemiology, Biostatistics and Bio-demography, Institute of Public Health, University of Southern Denmark, 5000, Odense C, Denmark
- Department of Psychology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Jenae M Neiderhiser
- Department of Psychology, The Pennsylvania State University, University Park, PA, USA
| | - Nancy L Pedersen
- Department of Psychology, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, 17177, Stockholm, Sweden
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20
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Olfactory memory in the old and very old: relations to episodic and semantic memory and APOE genotype. Neurobiol Aging 2015; 38:118-126. [PMID: 26827650 DOI: 10.1016/j.neurobiolaging.2015.11.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 10/16/2015] [Accepted: 11/21/2015] [Indexed: 01/10/2023]
Abstract
The neuroanatomical organization that underlies olfactory memory is different from that of other memory types. The present work examines olfactory memory in an elderly population-based sample (Swedish National Study on Aging and Care in Kungsholmen) aged 60-100 years (n = 2280). We used structural equation modeling to investigate whether olfactory memory in old age is best conceptualized as a distinct category, differentiated from episodic and semantic memory. Further, potential olfactory dedifferentiation and genetic associations (APOE) to olfactory function in late senescence were investigated. Results are in support of a 3-factor solution where olfactory memory, as indexed by episodic odor recognition and odor identification, is modeled separately from episodic and semantic memory for visual and verbal information. Increasing age was associated with poorer olfactory memory performance, and observed age-related deficits were further exacerbated for carriers of the APOE ε4 allele; these effects tended to be larger for olfactory memory compared to episodic and semantic memory pertaining to other sensory systems (vision, auditory). Finally, stronger correlations between olfactory and episodic memory, indicating dedifferentiation, were observed in the older age groups.
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21
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Wehling EI, Lundervold AJ, Nordin S, Wollschlaeger D. Longitudinal Changes in Familiarity, Free and Cued Odor Identification, and Edibility Judgments for Odors in Aging Individuals. Chem Senses 2015; 41:155-61. [PMID: 26547014 DOI: 10.1093/chemse/bjv066] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This longitudinal study investigated changes in olfaction as assessed by a set of tasks requiring different aspects of semantic information in normal aging individuals. Using 16 odorous items from a standardized olfactory test, the Scandinavian Odor Identification Test, 107 middle aged and older adults were assessed up to three times over a period of 6.5 years, requesting them to rate familiarity and edibility for each odorous item before identifying it with or without presenting verbal cues. Using linear mixed models, the longitudinal analyses revealed significant correlations between all olfactory measures. Furthermore, we found an almost parallel age-related decline in all olfactory tasks, although free identification performance indicated a trend toward faster decline with age. Women showed less decline compared with men, in particular for edibility judgments. The results corroborate earlier cross-sectional findings showing significant correlations between the olfactory tasks. In the present study of healthy middle-aged and older adults, we found a parallel longitudinal decline across different tests of olfaction.
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Affiliation(s)
- Eike I Wehling
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway, Kavli Centre for Aging and Dementia Research, Haraldsplass Hospital, Bergen, Norway, Department for Physical Medicine and Rehabilitation, Haukeland University Hospital, Bergen, Norway,
| | - Astri J Lundervold
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway, K. G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway
| | - Steven Nordin
- Department of Psychology, University of Umeå, Sweden and
| | - Daniel Wollschlaeger
- Institute for Medical Statistics, Epidemiology and Informatics, University Medical Center, Johannes-Gutenberg-University Mainz, Mainz, Germany
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22
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Grashow R, Sparrow D, Hu H, Weisskopf MG. Cumulative lead exposure is associated with reduced olfactory recognition performance in elderly men: The Normative Aging Study. Neurotoxicology 2015; 49:158-64. [PMID: 26121922 DOI: 10.1016/j.neuro.2015.06.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 06/05/2015] [Accepted: 06/23/2015] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Olfactory dysfunction has been identified as an early warning sign for Alzheimer's disease, Parkinson's disease, dementia and more. A few occupational and environmental exposures have also been associated with reduced olfactory function, although the effects of long term environmental exposure to lead on olfactory dysfunction have not been explored. Here we performed olfactory recognition testing in elderly men in a community-dwelling cohort and examined the association with cumulative lead exposure, as assessed by lead in tibial and patellar bone. METHODS Olfactory recognition was measured in 165 men from the Normative Aging Study (NAS) who had previously taken part in bone lead measurements using K-X-ray fluorescence (KXRF). Olfactory recognition was measured using the University of Pennsylvania Smell Identification Test (UPSIT). Associations between olfactory recognition, global cognition and cumulative lead exposure were estimated using linear regression, with additional adjustment for age, smoking, and functional polymorphism status for hemochromatosis (HFE), transferrin (TfC2), glutathione-s-transferase Pi1 (GSTP1) and apolipoprotein E (APOE) genotypes. Sensitivity analyses explored olfactory recognition in men with high global cognitive function as measured using the Mini-Mental Status Exam (MMSE). RESULTS The average age of the NAS participants at the time of olfactory recognition testing was 80.3 (standard deviation or SD=5.7) years. Mean tibia lead was 16.3 (SD=12.0) μg/g bone, mean patella lead was 22.4 (SD=14.4)μg/g bone, and mean UPSIT score was 26.9 out of 40 (SD=7.0). Consistent with previous findings, age at olfaction testing was negatively associated with UPSIT score. Tibia (but not patella) bone lead was negatively associated with olfaction recognition (per 15 μg/g tibia lead: β=-1.57; 95% CI: -2.93, -0.22; p=0.02) in models adjusted for smoking and age. Additional adjustment for education did not significantly change results. Of all the genes explored, only the presence of one or more HFE variant alleles was significantly associated with olfaction recognition (HFE β=2.26; 95% CI: 0.09, 4.43; p=0.04). In a model containing the HFE term and a lead term, the tibia lead parameter estimate dropped by 21% (per 15 μg/g tibia lead: β=-1.25; 95% CI: -2.64, 0.14; p=0.08) while the HFE term dropped 15% (β=1.91; 95% CI: -0.28, 4.10; p=0.09). None of the other gene terms were associated with olfactory recognition in this cohort, nor were any gene-lead interaction terms significant. Additional sensitivity analysis in men with MMSE scores of 25 or higher (n=149) showed a similar but slightly attenuated association between lead and olfactory recognition (per 15 μg/g tibia lead β=-1.39; 95% CI: -3.00, 0.22; p=0.09). CONCLUSION Cumulative exposure to lead is associated with reduced olfactory recognition in a cohort of elderly men. The association was similar but not significant in men with better cognitive function as measured by the MMSE. Iron metabolism gene status may also affect olfactory function.
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Affiliation(s)
- Rachel Grashow
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Civil and Environmental Engineering, Northeastern University, Boston, MA, USA.
| | - David Sparrow
- VA Boston Healthcare System, Boston University Schools of Public Health and Medicine, Boston, MA, USA; Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Howard Hu
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| | - Marc G Weisskopf
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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Reynolds CA, Finkel D. A meta-analysis of heritability of cognitive aging: minding the "missing heritability" gap. Neuropsychol Rev 2015; 25:97-112. [PMID: 25732892 DOI: 10.1007/s11065-015-9280-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Accepted: 01/26/2015] [Indexed: 12/19/2022]
Abstract
The etiologies underlying variation in adult cognitive performance and cognitive aging have enjoyed much attention in the literature, but much of that attention has focused on broad factors, principally general cognitive ability. The current review provides meta-analyses of age trends in heritability of specific cognitive abilities and considers the profile of genetic and environmental factors contributing to cognitive aging to address the 'missing heritability' issue. Our findings, based upon evaluating 27 reports in the literature, indicate that verbal ability demonstrated declining heritability, after about age 60, as did spatial ability and perceptual speed more modestly. Trends for general memory, working memory, and spatial ability generally indicated stability, or small increases in heritability in mid-life. Equivocal results were found for executive function. A second meta-analysis then considered the gap between twin-based versus SNP-based heritability derived from population-based GWAS studies. Specifically, we considered twin correlation ratios to agnostically re-evaluate biometrical models across age and by cognitive domain. Results modestly suggest that nonadditive genetic variance may become increasingly important with age, especially for verbal ability. If so, this would support arguments that lower SNP-based heritability estimates result in part from uncaptured non-additive influences (e.g., dominance, gene-gene interactions), and possibly gene-environment (GE) correlations. Moreover, consistent with longitudinal twin studies of aging, as rearing environment becomes a distal factor, increasing genetic variance may result in part from nonadditive genetic influences or possible GE correlations. Sensitivity to life course dynamics is crucial to understanding etiological contributions to adult cognitive performance and cognitive aging.
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Affiliation(s)
- Chandra A Reynolds
- Department of Psychology, University of California Riverside, Riverside, CA, 92521, USA,
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24
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Lundervold AJ, Wollschläger D, Wehling E. Age and sex related changes in episodic memory function in middle aged and older adults. Scand J Psychol 2014; 55:225-32. [PMID: 24601911 PMCID: PMC4314696 DOI: 10.1111/sjop.12114] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 01/21/2014] [Indexed: 12/12/2022]
Abstract
Age-related change in episodic memory function is commonly reported in older adults. When detected on neuropsychological tests, it may still be difficult to distinguish normal from pathological changes. The present study investigates age-and sex-related changes in a group of healthy middle-aged and older adults, participating in a three-wave study on cognitive aging. The California Verbal Learning test (CVLT-II) was used to assess their episodic memory function. A cross-sectional analysis of results from the first wave showed higher performance in females than males, with a steeper age-related decline in males. This was confirmed in a longitudinal analysis using a mixed effects regression model, but with a lower age-related change and smaller difference between the sexes. Information about learning strategies and errors in the third wave turned out to contribute significantly to explain change in episodic memory function across the three waves. We argue that the results from the longitudinal analyses are generalizable to the population of healthy middle-aged and older individuals, and that they could be useful in guiding clinicians when evaluating individuals with respect to cognitive change.
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Affiliation(s)
- Astri J Lundervold
- Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway; Center for research on Aging and Dementia, Haraldsplass Deaconal Hospital, Bergen, Norway; K. G. Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Bergen, Norway
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25
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Schubert CR, Cruickshanks KJ, Fischer ME, Huang GH, Klein R, Pankratz N, Zhong W, Nondahl DM. Odor identification and cognitive function in the Beaver Dam Offspring Study. J Clin Exp Neuropsychol 2013; 35:669-76. [PMID: 23789858 DOI: 10.1080/13803395.2013.809701] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Olfactory impairment is associated with cognitive impairment in older adults but less is known about the association of olfactory impairment and cognitive function in middle-aged adults. The association between olfactory impairment and cognitive function tests of attention, processing speed, and executive and psychomotor function was explored in 2837 participants (21-84 years; mean age 49 years) in the Beaver Dam Offspring Study. Among middle-aged participants (aged 35-64 years), those with impairment on an odor identification test took significantly longer to complete the Trail Making Test (TMT-A and TMT-B) and the Grooved Peg Board (GPB) test, than those without olfactory impairment in regression models adjusted for multiple factors. Similar results were found for the TMT-A and TMT-B, but not the GPB, in the whole cohort. Olfactory impairment was associated with poorer performance on cognitive function tests in a primarily middle-aged cohort.
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Affiliation(s)
- Carla R Schubert
- a Department of Ophthalmology and Visual Sciences , University of Wisconsin School of Medicine and Public Health , Madison , WI , USA
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26
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Ertekin-Taner N, De Jager PL, Yu L, Bennett DA. Alternative Approaches in Gene Discovery and Characterization in Alzheimer's Disease. CURRENT GENETIC MEDICINE REPORTS 2013; 1:39-51. [PMID: 23482655 PMCID: PMC3584671 DOI: 10.1007/s40142-013-0007-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Uncovering the genetic risk and protective factors for complex diseases is of fundamental importance for advancing therapeutic and biomarker discoveries. This endeavor is particularly challenging for neuropsychiatric diseases where diagnoses predominantly rely on the clinical presentation, which may be heterogeneous, possibly due to the heterogeneity of the underlying genetic susceptibility factors and environmental exposures. Although genome-wide association studies of various neuropsychiatric diseases have recently identified susceptibility loci, there likely remain additional genetic risk factors that underlie the liability to these conditions. Furthermore, identification and characterization of the causal risk variant(s) in each of these novel susceptibility loci constitute a formidable task, particularly in the absence of any prior knowledge about their function or mechanism of action. Biologically relevant, quantitative phenotypes, i.e., endophenotypes, provide a powerful alternative to the more traditional, binary disease phenotypes in the discovery and characterization of susceptibility genes for neuropsychiatric conditions. In this review, we focus on Alzheimer's disease (AD) as a model neuropsychiatric disease and provide a synopsis of the recent literature on the use of endophenotypes in AD genetics. We highlight gene expression, neuropathology and cognitive endophenotypes in AD, with examples demonstrating the utility of these alternative approaches in the discovery of novel susceptibility genes and pathways. In addition, we discuss how these avenues generate testable hypothesis about the pathophysiology of genetic factors that have far-reaching implications for therapies.
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Affiliation(s)
- Nilüfer Ertekin-Taner
- Departments of Neurology and Neuroscience, Mayo Clinic Florida, 4500 San Pablo Road, Birdsall 3, Jacksonville, FL 32224 USA
| | - Phillip L. De Jager
- Departments of Neurology and Psychiatry, Program in Translational NeuroPsychiatric Genomics, Institute for the Neurosciences, Brigham and Women’s Hospital, 77 Avenue Louis Pasteur NRB168, Boston, MA 02115 USA
- Harvard Medical School, Boston, MA 02115 USA
- Program in Medical and Population Genetics, Broad Institute, 7 Cambridge Center, Cambridge, MA 02142 USA
| | - Lei Yu
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL 60612 USA
| | - David A. Bennett
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL 60612 USA
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