GLORIA

GEOMAR Library Ocean Research Information Access

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Material
Language
  • 1
    In: Human Genetics, Springer Science and Business Media LLC, Vol. 141, No. 1 ( 2022-01), p. 147-173
    Abstract: The combined impact of common and rare exonic variants in COVID-19 host genetics is currently insufficiently understood. Here, common and rare variants from whole-exome sequencing data of about 4000 SARS-CoV-2-positive individuals were used to define an interpretable machine-learning model for predicting COVID-19 severity. First, variants were converted into separate sets of Boolean features, depending on the absence or the presence of variants in each gene. An ensemble of LASSO logistic regression models was used to identify the most informative Boolean features with respect to the genetic bases of severity. The Boolean features selected by these logistic models were combined into an Integrated PolyGenic Score that offers a synthetic and interpretable index for describing the contribution of host genetics in COVID-19 severity, as demonstrated through testing in several independent cohorts. Selected features belong to ultra-rare, rare, low-frequency, and common variants, including those in linkage disequilibrium with known GWAS loci. Noteworthily, around one quarter of the selected genes are sex-specific. Pathway analysis of the selected genes associated with COVID-19 severity reflected the multi-organ nature of the disease. The proposed model might provide useful information for developing diagnostics and therapeutics, while also being able to guide bedside disease management.
    Type of Medium: Online Resource
    ISSN: 0340-6717 , 1432-1203
    RVK:
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 1459188-1
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    In: Alzheimer's & Dementia, Wiley, Vol. 16, No. S6 ( 2020-12)
    Abstract: Longitudinal studies of aging are central to identifying early predictors of and mechanisms underlying late‐life cognitive decline and dementia. However, these studies typically lack cognitive data from earlier ages. It is therefore unclear how peak young adult general cognitive ability (GCA) and maintenance of GCA from young adulthood impact subsequent cognitive trajectories. To further understand GCA change from young adulthood, we evaluated whether poor GCA maintenance coincided with accelerated brain aging and was associated with key contributors to cognitive decline in later life, namely, aggregate vascular risk and Alzheimer’s disease polygenic risk (AD‐PRS). Method In the Vietnam Era Twin Study of Aging (VETSA), 1173 individuals were administered the same measure of GCA at average age 20 and at three VETSA waves beginning at average age 56. GCA maintenance scores were created by residualizing VETSA baseline GCA on age 20 GCA. Thus, good GCA maintenance was based on observed relative to expected scores. VETSA baseline GCA and GCA maintenance scores were entered into mixed effects models to predict specific cognitive abilities across three VETSA waves (∼6 years apart). Associations between GCA maintenance scores and indices of accelerated brain aging, aggregate vascular risk, and AD‐PRS were evaluated. Result Better GCA maintenance was associated with better VETSA baseline memory, semantic fluency, general fluency, processing speed, executive function, and working memory. However, given equivalent age 56 GCA, those who declined in GCA from age 20 outperformed those with stable GCA in memory, verbal fluency, executive function, and working memory at age 56. Thus, despite poor cognitive maintenance, some element of high peak cognitive reserve in early adulthood still confers benefit. All specific cognitive abilities declined over time, but neither VETSA baseline GCA nor GCA maintenance predicted extent of decline. Poor GCA maintenance from young adulthood was associated with accelerated brain aging and aggregate vascular risk, but not AD‐PRS. Conclusion Both peak young adult GCA and GCA maintenance are important contributors to late midlife cognitive ability. Poor maintenance of GCA from young adulthood being associated with worse vascular health and coinciding with accelerated brain aging argues against a simple regression to the mean explanation.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2201940-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    In: Neurobiology of Aging, Elsevier BV, Vol. 109 ( 2022-01), p. 229-238
    Type of Medium: Online Resource
    ISSN: 0197-4580
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2022
    detail.hit.zdb_id: 1498414-3
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    In: Alzheimer's & Dementia: Translational Research & Clinical Interventions, Wiley, Vol. 8, No. 1 ( 2022-01)
    Abstract: Practice effects (PEs) on cognitive tests obscure decline, thereby delaying detection of mild cognitive impairment (MCI). Importantly, PEs may be present even when there are performance declines, if scores would have been even lower without prior test exposure. We assessed how accounting for PEs using a replacement‐participants method impacts incident MCI diagnosis. Methods Of 889 baseline cognitively normal (CN) Alzheimer's Disease Neuroimaging Initiative (ADNI) participants, 722 returned 1 year later (mean age = 74.9 ± 6.8 at baseline). The scores of test‐naïve demographically matched “replacement” participants who took tests for the first time were compared to returnee scores at follow‐up. PEs—calculated as the difference between returnee follow‐up scores and replacement participants scores—were subtracted from follow‐up scores of returnees. PE‐adjusted cognitive scores were then used to determine if individuals were below the impairment threshold for MCI. Cerebrospinal fluid amyloid beta, phosphorylated tau, and total tau were used for criterion validation. In addition, based on screening and recruitment numbers from a clinical trial of amyloid‐positive individuals, we estimated the effect of earlier detection of MCI by accounting for cognitive PEs on a hypothetical clinical trial in which the key outcome was progression to MCI. Results In the ADNI sample, PE‐adjusted scores increased MCI incidence by 19% ( P   〈  .001), increased proportion of amyloid‐positive MCI cases (+12%), and reduced proportion of amyloid‐positive CNs (–5%; P ’s  〈  .04). Additional calculations showed that the earlier detection and increased MCI incidence would also substantially reduce necessary sample size and study duration for a clinical trial of progression to MCI. Cost savings were estimated at ≈$5.41 million. Discussion Detecting MCI as early as possible is of obvious importance. Accounting for cognitive PEs with the replacement‐participants method leads to earlier detection of MCI, improved diagnostic accuracy, and can lead to multi‐million‐dollar cost reductions for clinical trials.
    Type of Medium: Online Resource
    ISSN: 2352-8737 , 2352-8737
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2832891-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    Online Resource
    Online Resource
    Cold Spring Harbor Laboratory ; 2019
    In:  Learning & Memory Vol. 26, No. 1 ( 2019-01), p. 20-23
    In: Learning & Memory, Cold Spring Harbor Laboratory, Vol. 26, No. 1 ( 2019-01), p. 20-23
    Abstract: Spatial memory impairment is well documented in old age; however, less is known about spatial memory during middle age. We examined the performance of healthy young, middle-aged, and older adults on a spatial memory task with varying levels of spatial similarity (distance). On low similarity trials, young adults significantly outperformed middle-aged adults, who significantly outperformed older adults ( P s 〈 0.05). On high similarity trials, young adults significantly outperformed middle-aged and older adults ( P s 〈 0.05); however, middle-aged and older adults did not differ. Subtle age-related changes in spatial memory may emerge during middle age, particularly when spatial similarity is high.
    Type of Medium: Online Resource
    ISSN: 1549-5485
    Language: English
    Publisher: Cold Spring Harbor Laboratory
    Publication Date: 2019
    detail.hit.zdb_id: 2022057-1
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    In: JAMA Psychiatry, American Medical Association (AMA), Vol. 80, No. 7 ( 2023-07-01), p. 718-
    Abstract: Subjective memory concern has long been considered a state-related indicator of impending cognitive decline or dementia. The possibility that subjective memory concern may itself be a heritable trait is largely ignored, yet such an association would substantially confound its use in clinical or research settings. Objective To assess the heritability and traitlike dimensions of subjective memory concern and its clinical correlates. Design, Setting, and Participants This longitudinal twin cohort study was conducted from 1967 to 2019 among male adults with a mean (SD) age of 37.75 (2.52) years to follow-up at mean ages of 56.15 (2.72), 61.50 (2.43), and 67.35 (2.57) years (hereafter, 38, 56, 62, and 67 years, respectively) in the Vietnam Era Twin Study of Aging. The study included a national community-dwelling sample with health, education, and lifestyle characteristics comparable to a general sample of US men in this age cohort. Participants were monozygotic and dizygotic twins randomly recruited from the Vietnam Era Twin Registry. Data were analyzed from May 2021 to December 2022. Main Outcomes and Measures Measures included subjective memory concern at 4 time points; objective memory, depressive symptoms, and anxiety at the last 3 time points; negative emotionality (trait neuroticism) at age 56 years; polygenic risk scores (PRSs) for neuroticism, depression, and Alzheimer disease; APOE genotype; and parental history of dementia. Primary outcomes were heritability and correlations between subjective memory concern and other measures. Results The sample included 1555 male adults examined at age 38 years, 520 at age 56 years (due to late introduction of subjective memory concern questions), 1199 at age 62 years, and 1192 at age 67 years. Phenotypically, subjective memory concerns were relatively stable over time. At age 56 years, subjective memory concern had larger correlations with depressive symptoms ( r , 0.32; 95% CI, 0.21 to 0.42), anxiety ( r , 0.36; 95% CI, 0.18 to 0.51), and neuroticism ( r , 0.34; 95% CI, 0.26 to 0.41) than with objective memory ( r , −0.24; 95% CI, −0.33 to −0.13). Phenotypic results were similar at ages 62 and 67 years. A best-fitting autoregressive twin model indicated that genetic influences on subjective memory concern accumulated and persisted over time ( h 2  = 0.26-0.34 from age 38-67 years). At age 56 years, genetic influences for subjective memory concern were moderately correlated with genetic influences for anxiety ( r , 0.36; 95% CI, 0.18 to 0.51), negative emotionality ( r , 0.51; 95% CI, 0.44-0.57), and depressive symptoms ( r , 0.20; 95% CI, 0.10 to 0.29) as well as objective memory ( r , −0.22; 95% CI, −0.30 to −0.14). Similar genetic correlations were seen at ages 62 and 67 years. The neuroticism PRS was associated with subjective memory concern at age 38 years ( r , 0.10; 95% CI, 0.03. to 0.18) and age 67 years ( r , 0.09; 95% CI, 0.01 to 0.16). Subjective memory concern was not associated with any Alzheimer disease risk measures. Conclusions and Relevance This cohort study found stable genetic influences underlying subjective memory concern dating back to age 38 years. Subjective memory concern had larger correlations with affect-related measures than with memory-related measures. Improving the utility of subjective memory concern as an indicator of impending cognitive decline and dementia may depend on isolating its statelike component from its traitlike component.
    Type of Medium: Online Resource
    ISSN: 2168-622X
    Language: English
    Publisher: American Medical Association (AMA)
    Publication Date: 2023
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    In: Frontiers in Aging Neuroscience, Frontiers Media SA, Vol. 14 ( 2022-4-25)
    Abstract: Cognitive practice effects (PEs) can delay detection of progression from cognitively unimpaired to mild cognitive impairment (MCI). They also reduce diagnostic accuracy as suggested by biomarker positivity data. Even among those who decline, PEs can mask steeper declines by inflating cognitive scores. Within MCI samples, PEs may increase reversion rates and thus impede detection of further impairment. Within an MCI sample at baseline, we evaluated how PEs impact prevalence, reversion rates, and dementia progression after 1 year. Methods We examined 329 baseline Alzheimer’s Disease Neuroimaging Initiative MCI participants (mean age = 73.1; SD = 7.4). We identified test-naïve participants who were demographically matched to returnees at their 1-year follow-up. Since the only major difference between groups was that one completed testing once and the other twice, comparison of scores in each group yielded PEs. PEs were subtracted from each test to yield PE-adjusted scores. Biomarkers included cerebrospinal fluid phosphorylated tau and amyloid beta. Cox proportional models predicted time until first dementia diagnosis using PE-unadjusted and PE-adjusted diagnoses. Results Accounting for PEs increased MCI prevalence at follow-up by 9.2% (272 vs. 249 MCI), and reduced reversion to normal by 28.8% (57 vs. 80 reverters). PEs also increased stability of single-domain MCI by 12.0% (164 vs. 147). Compared to PE-unadjusted diagnoses, use of PE-adjusted follow-up diagnoses led to a twofold increase in hazard ratios for incident dementia. We classified individuals as false reverters if they reverted to cognitively unimpaired status based on PE-unadjusted scores, but remained classified as MCI cases after accounting for PEs. When amyloid and tau positivity were examined together, 72.2% of these false reverters were positive for at least one biomarker. Interpretation Even when PEs are small, they can meaningfully change whether some individuals with MCI retain the diagnosis at a 1-year follow-up. Accounting for PEs resulted in increased MCI prevalence and altered stability/reversion rates. This improved diagnostic accuracy also increased the dementia-predicting ability of MCI diagnoses.
    Type of Medium: Online Resource
    ISSN: 1663-4365
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2558898-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    In: Brain Communications, Oxford University Press (OUP), Vol. 3, No. 3 ( 2021-07-01)
    Abstract: Neuroimaging signatures based on composite scores of cortical thickness and hippocampal volume predict progression from mild cognitive impairment to Alzheimer’s disease. However, little is known about the ability of these signatures among cognitively normal adults to predict progression to mild cognitive impairment. Towards that end, a signature sensitive to microstructural changes that may predate macrostructural atrophy should be useful. We hypothesized that: (i) a validated MRI-derived Alzheimer’s disease signature based on cortical thickness and hippocampal volume in cognitively normal middle-aged adults would predict progression to mild cognitive impairment; and (ii) a novel grey matter mean diffusivity signature would be a better predictor than the thickness/volume signature. This cohort study was part of the Vietnam Era Twin Study of Aging. Concurrent analyses compared cognitively normal and mild cognitive impairment groups at each of three study waves (ns = 246–367). Predictive analyses included 169 cognitively normal men at baseline (age = 56.1, range = 51–60). Our previously published thickness/volume signature derived from independent data, a novel mean diffusivity signature using the same regions and weights as the thickness/volume signature, age, and an Alzheimer’s disease polygenic risk score were used to predict incident mild cognitive impairment an average of 12 years after baseline (follow-up age = 67.2, range = 61–71). Additional analyses adjusted for predicted brain age difference scores (chronological age minus predicted brain age) to determine if signatures were Alzheimer-related and not simply ageing-related. In concurrent analyses, individuals with mild cognitive impairment had higher (worse) mean diffusivity signature scores than cognitively normal participants, but thickness/volume signature scores did not differ between groups. In predictive analyses, age and polygenic risk score yielded an area under the curve of 0.74 (sensitivity = 80.00%; specificity = 65.10%). Prediction was significantly improved with addition of the mean diffusivity signature (area under the curve = 0.83; sensitivity = 85.00%; specificity = 77.85%; P = 0.007), but not with addition of the thickness/volume signature. A model including both signatures did not improve prediction over a model with only the mean diffusivity signature. Results held up after adjusting for predicted brain age difference scores. The novel mean diffusivity signature was limited by being yoked to the thickness/volume signature weightings. An independently derived mean diffusivity signature may thus provide even stronger prediction. The young age of the sample at baseline is particularly notable. Given that the brain signatures were examined when participants were only in their 50 s, our results suggest a promising step towards improving very early identification of Alzheimer’s disease risk and the potential value of mean diffusivity and/or multimodal brain signatures.
    Type of Medium: Online Resource
    ISSN: 2632-1297
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 3020013-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 9
    In: Alzheimer's & Dementia, Wiley, Vol. 18, No. S1 ( 2022-12)
    Abstract: Composite scores of MRI‐based brain regions associated with Alzheimer’s disease (AD) pathology, commonly termed ‘AD signatures’, are tools developed to identify brain changes specific to mild AD. We found that a novel diffusion‐based cortical mean diffusivity (MD) signature among cognitively normal adults in their 50s aided prediction of 12‐year progression to MCI beyond age and polygenic risk for AD (Williams et al., Brain Communications , 2021). Results held up after accounting for general brain age. In contrast, a cortical thickness/hippocampal volume‐based signature did not improve prediction. Given the importance of genetic influences on brain structure and AD, we examined the phenotypic and genetic relationships among diffusion and structural AD signatures and brain age, and how those relationships change across midlife and early old age. Method Our validated thickness/volume signature, novel MD signature, and a validated brain age measure were used in biometrical twin analyses to examine phenotypic, genetic, and environmental relationships both cross‐sectionally and longitudinally across 12 years. Participants were 736 men from three waves of the Vietnam Era Twin Study of Aging (VETSA; baseline age=56.1, SD=2.6, range=51.1‐60.2). Subsequent waves were at approximately 5.7‐year intervals. Result Both AD signatures and brain age are heritable (56%‐72%), but each signature captured unique phenotypic and genetic variance that is also not explained by general brain aging. Genetic correlations across time within each signature were high (0.77‐0.98). Baseline MD signatures (age=56 years) predicted thickness/volume signatures over a decade later (r= ‐0.53, 95% CI: ‐0.62, ‐0.42), but baseline thickness/volume signatures showed a significantly weaker relationship with future MD signatures (r= ‐0.13, 95% CI: ‐0.24, ‐0.01). Interestingly, by wave 2 (average age=62 years), the thickness/volume signature appears to have caught up with the MD signature in terms of predictive ability. Conclusion Findings lend further support to the idea that a signature based on brain microstructure captures very early AD‐related changes that are later reflected in the macrostructural signature. This MD signature explains substantial genetic variance that is consistent throughout midlife and into early old age, supporting the utility of the MD signature as a very early AD‐related neuroimaging biomarker and its potential role in clinical trials.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2201940-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 10
    In: Alzheimer's & Dementia, Wiley, Vol. 17, No. S4 ( 2021-12)
    Abstract: Composite scores of MRI‐based brain morphometry, commonly termed ‘Alzheimer’s disease (AD) signatures,’ have demonstrated associations with AD symptom severity and progression to AD. Our group recently showed that two AD signatures, a cortical thickness/volume and mean diffusivity (MD) signature, aid prediction of progression to mild cognitive impairment among cognitively normal adults in their 50s. Genetic and environmental influences on these signatures, and whether the signatures capture unique AD‐related variance, remains unclear. Method Participants were from the Vietnam Era Twin Study of Aging (age=56.18, SD=2.61). Our previously published thickness/volume signature, a novel MD signature using the same regions and weights as the thickness/volume signature, and an MRI‐based measure of predicted brain age ( n s=310‐502) were used in trivariate twin models to determine the relative influence of genetic and environmental factors on each phenotype. Correlations were examined to determine if the latent genetic and environmental influences overlap among the three phenotypes. Result Heritability estimates were similar for the signatures and predicted brain age (0.68‐0.71). Phenotypic correlations ranged from ‐0.47 to 0.27. Genetic correlations were: 0.33 [95% CI: 0.19,0.47] (thickness/volume signature and predicted brain age); ‐0.55 [95% CI: ‐0.66,‐0.42] (MD signature and predicted brain age); and ‐0.36 [95% CI: ‐0.51,‐0.20] (thickness/volume and MD signatures). Conclusion Both AD brain signatures are highly heritable. However, despite very similar heritability estimates among the three phenotypes, genetic correlations demonstrated that the two AD signatures are not redundant with each other or with a measure of predicted brain age. The results suggest that each AD signature captures some unique genetic variance, including genetic influences that are distinct from genetic influences on general brain aging.
    Type of Medium: Online Resource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2201940-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...