Publications by authors named "Michael J Lyons"

223 Publications

Long-term Associations of Cigarette Smoking in Early Midlife with Predicted Brain Aging from Midlife to Late Life.

Addiction 2021 Oct 4. Epub 2021 Oct 4.

Department of Psychiatry, University of California San Diego, La Jolla, CA, USA.

Background And Aims: Smoking is associated with increased risk for brain aging/atrophy and dementia. Few studies have examined early associations with brain aging. This study aimed to measure whether adult men with a history of heavier smoking in early midlife would have older than predicted brain age 16 to 28 years later.

Design: Prospective cohort observational study, utilizing smoking pack years data from average age 40 (early midlife) predicting predicted brain age difference scores (PBAD) at average ages 56, 62 (later midlife) and 68 (early old age). Early midlife alcohol use was also evaluated.

Setting: Population-based United States sample.

Participants/cases: Participants were male twins of predominantly European ancestry who served in the United States military sometime between 1965 and 1975. Structural magnetic resonance imaging (MRI) began at average age 56. Subsequent study waves included most baseline participants; attrition replacement subjects were added at later waves.

Measurements: Self-reported smoking information was used to calculate pack years smoked at ages 40, 56, 62, and 68. MRIs were processed with the BARACUS program to create PBAD scores (chronological age - predicted brain age) acquired at average ages 56 (N=493; 2002-08), 62 (N=408; 2009-14), and 68 (N=499; 2016-19).

Findings: In structural equation modelling, age 40 pack years predicted more advanced age 56 PBAD (β = -0.144, p = 0.012, 95% confidence interval (CI) -0.257, -0.032). Age 40 pack years did not additionally predict PBAD at later ages. Age 40 alcohol consumption, but not a smoking-by-alcohol interaction, predicted more advanced PBAD at age 56 (β = -0.166, p=0.001, 95%CI -0.261,-0.070) with additional influences at age 62 (β = -0.115, p = 0.005, 95%CI -0.195,-0.036). Age 40 alcohol did not predict age 68 PBAD. Within-twin pair analyses suggested some genetic mechanism partially underlying effects of alcohol, but not smoking, on PBAD.

Conclusions: Heavier smoking and alcohol consumption by age 40 appears to predict advanced brain aging by age 56 in men.
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http://dx.doi.org/10.1111/add.15710DOI Listing
October 2021

Lifestyle and the aging brain: interactive effects of modifiable lifestyle behaviors and cognitive ability in men from midlife to old age.

Neurobiol Aging 2021 Aug 19;108:80-89. Epub 2021 Aug 19.

Department of Psychiatry, University of California San Diego, San Diego, CA, USA; Center for Behavior Genetics of Aging, University of California San Diego, San Diego, CA, USA.

We examined the influence of lifestyle on brain aging after nearly 30 years, and tested the hypothesis that young adult general cognitive ability (GCA) would moderate these effects. In the community-dwelling Vietnam Era Twin Study of Aging (VETSA), 431 largely non-Hispanic white men completed a test of GCA at mean age 20. We created a modifiable lifestyle behavior composite from data collected at mean age 40. During VETSA, MRI-based measures at mean age 68 included predicted brain age difference (PBAD), Alzheimer's disease (AD) brain signature, and abnormal white matter scores. There were significant main effects of young adult GCA and lifestyle on PBAD and the AD signature (ps ≤ 0.012), and a GCA-by-lifestyle interaction on both (ps ≤ 0.006). Regardless of GCA level, having more favorable lifestyle behaviors predicted less advanced brain age and less AD-like brain aging. Unfavorable lifestyles predicted advanced brain aging in those with lower age 20 GCA, but did not affect brain aging in those with higher age 20 GCA. Targeting early lifestyle modification may promote dementia risk reduction, especially among lower reserve individuals.
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http://dx.doi.org/10.1016/j.neurobiolaging.2021.08.007DOI Listing
August 2021

12-year prediction of mild cognitive impairment aided by Alzheimer's brain signatures at mean age 56.

Brain Commun 2021 23;3(3):fcab167. Epub 2021 Jul 23.

Center for Behavior Genetics of Aging, University of California San Diego, La Jolla, CA 92093, USA.

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 (s = 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%;  = 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.
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http://dx.doi.org/10.1093/braincomms/fcab167DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8361427PMC
July 2021

How Well Does Subjective Cognitive Decline Correspond to Objectively Measured Cognitive Decline? Assessment of 10-12 Year Change.

J Alzheimers Dis 2021 ;83(1):291-304

Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA.

Background: Although not strongly correlated with current objective cognitive ability, subjective cognitive decline (SCD) is a risk factor for Alzheimer's disease. Most studies focus on SCD in relation to future decline rather than objective prior decline that it purportedly measures.

Objective: We evaluated whether self-report of cognitive decline-as a continuous measure-corresponds to objectively-assessed episodic memory and executive function decline across the same period.

Methods: 1,170 men completed the Everyday Cognition Questionnaire (ECog) at mean age 68 assessing subjective changes in cognitive ability relative to 10 years prior. A subset had mild cognitive impairment (MCI), but MCI was diagnosed without regard to subjective decline. Participants completed up to 3 objective assessments of memory and executive function (M = 56, 62, and 68 years). Informant-reported ECogs were completed for 1,045 individuals. Analyses controlled for depression and anxiety symptoms assessed at mean age 68.

Results: Participant-reported ECog scores were modestly associated with objective decline for memory (β= -0.23, 95%CI [-0.37, -0.10]) and executive function (β= -0.19, 95%CI [-0.33, -0.05]) over the same time period. However, these associations were nonsignificant after excluding MCI cases. Results were similar for informant ratings. Participant-rated ECog scores were more strongly associated with concurrent depression and anxiety symptoms, (β= 0.44, 95%CI [0.36, 0.53]).

Conclusion: Continuous SCD scores are correlated with prior objective cognitive changes in non-demented individuals, though this association appears driven by individuals with current MCI. However, participants' current depression and anxiety ratings tend to be strongly associated with their SCD ratings. Thus, what primarily drives SCD ratings remains unclear.
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http://dx.doi.org/10.3233/JAD-210123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8482061PMC
January 2021

Examining Individual and Synergistic Contributions of PTSD and Genetics to Blood Pressure: A Trans-Ethnic Meta-Analysis.

Front Neurosci 2021 23;15:678503. Epub 2021 Jun 23.

Department of Psychiatry, Case Western Reserve University, Cleveland, OH, United States.

Growing research suggests that posttraumatic stress disorder (PTSD) may be a risk factor for poor cardiovascular health, and yet our understanding of who might be at greatest risk of adverse cardiovascular outcomes after trauma is limited. In this study, we conducted the first examination of the individual and synergistic contributions of PTSD symptoms and blood pressure genetics to continuous blood pressure levels. We harnessed the power of the Psychiatric Genomics Consortium-PTSD Physical Health Working Group and investigated these associations across 11 studies of 72,224 trauma-exposed individuals of European ( = 70,870) and African ( = 1,354) ancestry. Genetic contributions to blood pressure were modeled via polygenic scores (PGS) for systolic blood pressure (SBP) and diastolic blood pressure (DBP) that were derived from a prior trans-ethnic blood pressure genome-wide association study (GWAS). Results of trans-ethnic meta-analyses revealed significant main effects of the PGS on blood pressure levels [SBP: β = 2.83, standard error (SE) = 0.06, < 1E-20; DBP: β = 1.32, SE = 0.04, < 1E-20]. Significant main effects of PTSD symptoms were also detected for SBP and DBP in trans-ethnic meta-analyses, though there was significant heterogeneity in these results. When including data from the largest contributing study - United Kingdom Biobank - PTSD symptoms were negatively associated with SBP levels (β = -1.46, SE = 0.44, = 9.8E-4) and positively associated with DBP levels (β = 0.70, SE = 0.26, = 8.1E-3). However, when excluding the United Kingdom Biobank cohort in trans-ethnic meta-analyses, there was a nominally significant positive association between PTSD symptoms and SBP levels (β = 2.81, SE = 1.13, = 0.01); no significant association was observed for DBP (β = 0.43, SE = 0.78, = 0.58). Blood pressure PGS did not significantly moderate the associations between PTSD symptoms and blood pressure levels in meta-analyses. Additional research is needed to better understand the extent to which PTSD is associated with high blood pressure and how genetic as well as contextual factors may play a role in influencing cardiovascular risk.
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http://dx.doi.org/10.3389/fnins.2021.678503DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8262489PMC
June 2021

Syndromic neurodevelopmental disorder associated with de novo variants in DDX23.

Am J Med Genet A 2021 10 29;185(10):2863-2872. Epub 2021 May 29.

Greenwood Genetic Center, Greenwood, South Carolina, USA.

The DEAD/DEAH box RNA helicases are a superfamily of proteins involved in the processing and transportation of RNA within the cell. A growing literature supports this family of proteins as contributing to various types of human disorders from neurodevelopmental disorders to syndromes with multiple congenital anomalies. This article presents a cohort of nine unrelated individuals with de novo missense alterations in DDX23 (Dead-Box Helicase 23). The gene is ubiquitously expressed and functions in RNA splicing, maintenance of genome stability, and the sensing of double-stranded RNA. Our cohort of patients, gathered through GeneMatcher, exhibited features including tone abnormalities, global developmental delay, facial dysmorphism, autism spectrum disorder, and seizures. Additionally, there were a variety of other findings in the skeletal, renal, ocular, and cardiac systems. The missense alterations all occurred within a highly conserved RecA-like domain of the protein, and are located within or proximal to the DEAD box sequence. The individuals presented in this article provide evidence of a syndrome related to alterations in DDX23 characterized predominantly by atypical neurodevelopment.
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http://dx.doi.org/10.1002/ajmg.a.62359DOI Listing
October 2021

CSNK2B: A broad spectrum of neurodevelopmental disability and epilepsy severity.

Epilepsia 2021 07 26;62(7):e103-e109. Epub 2021 May 26.

Department of Neuropediatrics, APHP Sorbonne University, Trousseau Hospital, Paris, France.

CSNK2B has recently been implicated as a disease gene for neurodevelopmental disability (NDD) and epilepsy. Information about developmental outcomes has been limited by the young age and short follow-up for many of the previously reported cases, and further delineation of the spectrum of associated phenotypes is needed. We present 25 new patients with variants in CSNK2B and refine the associated NDD and epilepsy phenotypes. CSNK2B variants were identified by research or clinical exome sequencing, and investigators from different centers were connected via GeneMatcher. Most individuals had developmental delay and generalized epilepsy with onset in the first 2 years. However, we found a broad spectrum of phenotypic severity, ranging from early normal development with pharmacoresponsive seizures to profound intellectual disability with intractable epilepsy and recurrent refractory status epilepticus. These findings suggest that CSNK2B should be considered in the diagnostic evaluation of patients with a broad range of NDD with treatable or intractable seizures.
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http://dx.doi.org/10.1111/epi.16931DOI Listing
July 2021

Periventricular and deep abnormal white matter differ in associations with cognitive performance at midlife.

Neuropsychology 2021 Mar;35(3):252-264

Center for Behavior Genetics of Aging, University of California.

Abnormal white matter (AWM) on magnetic resonance imaging is associated with cognitive performance in older adults. We explored cognitive associations with AWM during late-midlife. Participants were community-dwelling men ( = 242; = 61.90 years; range = 56-66). Linear-mixed effects regression models examined associations of total, periventricular, and deep AWM with cognitive performance, controlling for multiple comparisons. Models considering specific cognitive domains controlled for current general cognitive ability (GCA). We hypothesized that total AWM would be associated with worse processing speed, executive function, and current GCA; deep AWM would correlate with GCA and periventricular AWM would relate to specific cognitive abilities. We also assessed the potential influence of cognitive reserve by examining a moderation effect of early life (mean age of 20) cognition. Greater total and deep AWM were associated with poorer current GCA. Periventricular AWM was associated with worse executive function, working memory, and episodic memory. When periventricular and deep AWM were modeled simultaneously, both retained their respective significant associations with cognitive performance. Cognitive reserve did not moderate associations. Our findings suggest that AWM contributes to poorer cognitive function in late-midlife. Examining only total AWM may obscure the potential differential impact of regional AWM. Separating total AWM into subtypes while controlling for current GCA revealed a dissociation in relationships with cognitive performance; deep AWM was associated with nonspecific cognitive ability whereas periventricular AWM was associated with specific frontal-related abilities and memory. Management of vascular or other risk factors that may increase the risk of AWM should begin during or before early late-midlife. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
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http://dx.doi.org/10.1037/neu0000718DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8500190PMC
March 2021

Missense and truncating variants in CHD5 in a dominant neurodevelopmental disorder with intellectual disability, behavioral disturbances, and epilepsy.

Hum Genet 2021 Jul 4;140(7):1109-1120. Epub 2021 May 4.

CHU Sainte-Justine Research Center, Montreal, QC, H3T 1C5, Canada.

Located in the critical 1p36 microdeletion region, the chromodomain helicase DNA-binding protein 5 (CHD5) gene encodes a subunit of the nucleosome remodeling and deacetylation (NuRD) complex required for neuronal development. Pathogenic variants in six of nine chromodomain (CHD) genes cause autosomal dominant neurodevelopmental disorders, while CHD5-related disorders are still unknown. Thanks to GeneMatcher and international collaborations, we assembled a cohort of 16 unrelated individuals harboring heterozygous CHD5 variants, all identified by exome sequencing. Twelve patients had de novo CHD5 variants, including ten missense and two splice site variants. Three familial cases had nonsense or missense variants segregating with speech delay, learning disabilities, and/or craniosynostosis. One patient carried a frameshift variant of unknown inheritance due to unavailability of the father. The most common clinical features included language deficits (81%), behavioral symptoms (69%), intellectual disability (64%), epilepsy (62%), and motor delay (56%). Epilepsy types were variable, with West syndrome observed in three patients, generalized tonic-clonic seizures in two, and other subtypes observed in one individual each. Our findings suggest that, in line with other CHD-related disorders, heterozygous CHD5 variants are associated with a variable neurodevelopmental syndrome that includes intellectual disability with speech delay, epilepsy, and behavioral problems as main features.
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http://dx.doi.org/10.1007/s00439-021-02283-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8197709PMC
July 2021

Lysosomal cholesterol accumulation contributes to the movement phenotypes associated with NUS1 haploinsufficiency.

Genet Med 2021 07 17;23(7):1305-1314. Epub 2021 Mar 17.

Greenwood Genetic Center, Greenwood, SC, USA.

Purpose: Variants in NUS1 are associated with a congenital disorder of glycosylation, developmental and epileptic encephalopathies, and are possible contributors to Parkinson disease pathogenesis. How the diverse functions of the NUS1-encoded Nogo B receptor (NgBR) relate to these different phenotypes is largely unknown. We present three patients with de novo heterozygous variants in NUS1 that cause a complex movement disorder, define pathogenic mechanisms in cells and zebrafish, and identify possible therapy.

Methods: Comprehensive functional studies were performed using patient fibroblasts, and a zebrafish model mimicking NUS1 haploinsufficiency.

Results: We show that de novo NUS1 variants reduce NgBR and Niemann-Pick type C2 (NPC2) protein amount, impair dolichol biosynthesis, and cause lysosomal cholesterol accumulation. Reducing nus1 expression 50% in zebrafish embryos causes abnormal swim behaviors, cholesterol accumulation in the nervous system, and impaired turnover of lysosomal membrane proteins. Reduction of cholesterol buildup with 2-hydroxypropyl-ß-cyclodextrin significantly alleviates lysosomal proteolysis and motility defects.

Conclusion: Our results demonstrate that these NUS1 variants cause multiple lysosomal phenotypes in cells. We show that the movement deficits associated with nus1 reduction in zebrafish arise in part from defective efflux of cholesterol from lysosomes, suggesting that treatments targeting cholesterol accumulation could be therapeutic.
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http://dx.doi.org/10.1038/s41436-021-01137-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8263489PMC
July 2021

MRI-assessed locus coeruleus integrity is heritable and associated with multiple cognitive domains, mild cognitive impairment, and daytime dysfunction.

Alzheimers Dement 2021 06 13;17(6):1017-1025. Epub 2021 Feb 13.

Department of Psychiatry, University of California San Diego, La Jolla, California, USA.

Introduction: The locus coeruleus (LC) undergoes extensive neurodegeneration in early Alzheimer's disease (AD). The LC is implicated in regulating the sleep-wake cycle, modulating cognitive function, and AD progression.

Methods: Participants were 481 men (ages 62 to 71.7) from the Vietnam Era Twin Study of Aging. LC structural integrity was indexed by neuromelanin-sensitive magnetic resonance imaging (MRI) contrast-to-noise ratio (LC ). We examined LC , cognition, amnestic mild cognitive impairment (aMCI), and daytime dysfunction.

Results: Heritability of LC was .48. Participants with aMCI showed greater daytime dysfunction. Lower LC was associated with poorer episodic memory, general verbal fluency, semantic fluency, and processing speed, as well as increased odds of aMCI and greater daytime dysfunction.

Discussion: Reduced LC integrity is associated with widespread differences across cognitive domains, daytime sleep-related dysfunction, and risk for aMCI. These findings in late-middle-aged adults highlight the potential of MRI-based measures of LC integrity in early identification of AD risk.
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http://dx.doi.org/10.1002/alz.12261DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8248066PMC
June 2021

Epithelioid Sarcoma Arising in a Long-Term Survivor of an Atypical Teratoid/Rhabdoid Tumor in a Patient With Rhabdoid Tumor Predisposition Syndrome.

Pediatr Dev Pathol 2021 Mar-Apr;24(2):164-168. Epub 2021 Jan 20.

Department of Pathology and Laboratory, Medical University of South Carolina, Charleston, South Carolina.

Rhabdoid tumor predisposition syndrome (RTPS) is defined as the presence of a or genetic aberration in a patient with malignant rhabdoid tumor. Patients with RTPS are more likely to present with synchronous or metachronous rhabdoid tumors. Based on the current state of rhabdoid tumor taxonomy, these diagnoses are based largely on patient demographics, anatomic location of disease, and immunohistochemistry, despite their nearly identical histologic and immunohistochemical profiles. Thus, the true distinction between such tumors remains a diagnostic challenge. Central nervous system atypical teratoid/rhabdoid tumor (AT/RT) is a rare, aggressive, primarily pediatric malignancy with variable histologic features and a well documented association with loss of SMARCB1 expression. Epithelioid sarcoma (ES) is a rare soft tissue tumor arising in patients of all ages and characteristically staining for both mesenchymal and epithelial immunohistochemical markers while usually demonstrating loss of SMARCB1 expression. To our knowledge we herein present the first documented case of a patient with RTPS who presented with metachronous AT/RT and ES.
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http://dx.doi.org/10.1177/1093526620986492DOI Listing
January 2021

Associations between depression and cardiometabolic health: A 27-year longitudinal study.

Psychol Med 2021 Jan 12:1-11. Epub 2021 Jan 12.

Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA.

Background: Clarifying the relationship between depression symptoms and cardiometabolic and related health could clarify risk factors and treatment targets. The objective of this study was to assess whether depression symptoms in midlife are associated with the subsequent onset of cardiometabolic health problems.

Methods: The study sample comprised 787 male twin veterans with polygenic risk score data who participated in the Harvard Twin Study of Substance Abuse ('baseline') and the longitudinal Vietnam Era Twin Study of Aging ('follow-up'). Depression symptoms were assessed at baseline [mean age 41.42 years (s.d. = 2.34)] using the Diagnostic Interview Schedule, Version III, Revised. The onset of eight cardiometabolic conditions (atrial fibrillation, diabetes, erectile dysfunction, hypercholesterolemia, hypertension, myocardial infarction, sleep apnea, and stroke) was assessed via self-reported doctor diagnosis at follow-up [mean age 67.59 years (s.d. = 2.41)].

Results: Total depression symptoms were longitudinally associated with incident diabetes (OR 1.29, 95% CI 1.07-1.57), erectile dysfunction (OR 1.32, 95% CI 1.10-1.59), hypercholesterolemia (OR 1.26, 95% CI 1.04-1.53), and sleep apnea (OR 1.40, 95% CI 1.13-1.74) over 27 years after controlling for age, alcohol consumption, smoking, body mass index, C-reactive protein, and polygenic risk for specific health conditions. In sensitivity analyses that excluded somatic depression symptoms, only the association with sleep apnea remained significant (OR 1.32, 95% CI 1.09-1.60).

Conclusions: A history of depression symptoms by early midlife is associated with an elevated risk for subsequent development of several self-reported health conditions. When isolated, non-somatic depression symptoms are associated with incident self-reported sleep apnea. Depression symptom history may be a predictor or marker of cardiometabolic risk over decades.
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http://dx.doi.org/10.1017/S003329172000505XDOI Listing
January 2021

Metabolites Associated with Early Cognitive Changes Implicated in Alzheimer's Disease.

J Alzheimers Dis 2021 ;79(3):1041-1054

Department of Population Health Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.

Background: Understanding metabolic mechanisms associated with cognitive changes preceding an Alzheimer's disease (AD) diagnosis could advance our understanding of AD progression and inform preventive methods.

Objective: We investigated the metabolomics of the early changes in executive function and delayed recall, the earliest aspects of cognitive function to change in the course of AD development, in order to better understand mechanisms that could contribute to early stages and progression of this disease.

Methods: This investigation used longitudinal plasma samples from the Wisconsin Registry for Alzheimer's Prevention (WRAP), a cohort of participants who were dementia free at enrollment and enriched with a parental history of AD. Metabolomic profiles were quantified for 2,324 fasting plasma samples among 1,200 participants, each with up to three study visits, which occurred every two years. Metabolites were individually tested for association with executive function and delayed recall trajectories across age.

Results: Of 1,097 metabolites tested, levels of seven were associated with executive function trajectories, including an amino acid cysteine S-sulfate and three fatty acids, including erucate (22 : 1n9), while none were associated with delayed recall trajectories. Replication was attempted for four of these metabolites that were present in the Vietnam Era Twin Study of Aging (VETSA). Although none reached statistical significance, three of these associations showed consistent effectdirections.

Conclusion: Our results suggest potential metabolomic mechanisms that could contribute to the earliest signs of cognitive decline. In particular, fatty acids may be associated with cognition in a manner that is more complex than previously suspected.
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http://dx.doi.org/10.3233/JAD-200176DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8054536PMC
September 2021

Histone H3.3 beyond cancer: Germline mutations in cause a previously unidentified neurodegenerative disorder in 46 patients.

Sci Adv 2020 Dec 2;6(49). Epub 2020 Dec 2.

Institut für Neurogenomik, Helmholtz Zentrum München, Munich, Germany.

Although somatic mutations in Histone 3.3 (H3.3) are well-studied drivers of oncogenesis, the role of germline mutations remains unreported. We analyze 46 patients bearing de novo germline mutations in histone 3 family 3A () or with progressive neurologic dysfunction and congenital anomalies without malignancies. Molecular modeling of all 37 variants demonstrated clear disruptions in interactions with DNA, other histones, and histone chaperone proteins. Patient histone posttranslational modifications (PTMs) analysis revealed notably aberrant local PTM patterns distinct from the somatic lysine mutations that cause global PTM dysregulation. RNA sequencing on patient cells demonstrated up-regulated gene expression related to mitosis and cell division, and cellular assays confirmed an increased proliferative capacity. A zebrafish model showed craniofacial anomalies and a defect in Foxd3-derived glia. These data suggest that the mechanism of germline mutations are distinct from cancer-associated somatic histone mutations but may converge on control of cell proliferation.
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http://dx.doi.org/10.1126/sciadv.abc9207DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7821880PMC
December 2020

Metabolic Profiling of Cognitive Aging in Midlife.

Front Aging Neurosci 2020 5;12:555850. Epub 2020 Nov 5.

Department of Epidemiology, University of Florida, Gainesville, FL, United States.

Alzheimer's dementia (AD) begins many years before its clinical symptoms. Metabolic dysfunction represents a core feature of AD and cognitive impairment, but few metabolomic studies have focused on cognitive aging in midlife. Using an untargeted metabolomics approach, we identified metabolic predictors of cognitive aging in midlife using fasting plasma sample from 30 middle-aged (mean age 57.2), male-male twin pairs enrolled in the Vietnam Era Twin Study of Aging (VETSA). For all twin pairs, one twin developed incident MCI, whereas his co-twin brother remained to be cognitively normal during an average 5.5-year follow-up. Linear mixed model was used to identify metabolites predictive of MCI conversion or cognitive change over time, adjusting for traditional risk factors. Results from twins were replicated in an independent cohort of middle-aged adults (mean age 59.1) in the Wisconsin Registry for Alzheimer's Prevention (WRAP). Results in twins showed that higher baseline levels of four plasma metabolites, including sphingomyelin (d18:1/20:1 and d18:2/20:0), sphingomyelin (d18:1/22:1, d18:2/22:0, and d16:1/24:1), DAG (18:2/20:4), and hydroxy-CMPF, were significantly associated with a slower decrease in one or more domains of cognitive function. The association of sphingomyelin (d18:1/20:1 and d18:2/20:0) was replicated in WRAP. Our results support that metabolic perturbation occurs many years before cognitive impairment and plasma metabolites may serve as early biomarkers for prediction or monitoring of cognitive aging and AD in midlife.
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http://dx.doi.org/10.3389/fnagi.2020.555850DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7674168PMC
November 2020

Cognitive Practice Effects Delay Diagnosis; Implications for Clinical Trials.

medRxiv 2020 Nov 5. Epub 2020 Nov 5.

Objective: Practice effects on cognitive tests obscure decline, thereby delaying detection of mild cognitive impairment (MCI). This reduces opportunities for slowing Alzheimer's disease progression and can hinder clinical trials. Using a novel method, we assessed the ability of practice-effect-adjusted diagnoses to detect MCI earlier, and tested the validity of these diagnoses based on AD biomarkers.

Methods: Of 889 Alzheimer's Disease Neuroimaging Initiative participants who were cognitively normal (CN) at baseline, 722 returned at 1-year-follow-up (mean age=74.9±6.8). Practice effects were calculated by comparing returnee scores at follow-up to demographically-matched individuals who had only taken the tests once, with an additional adjustment for attrition effects. Practice effects for each test were subtracted from follow-up scores. The lower scores put additional individuals below the impairment threshold for MCI. CSF amyloid-beta, phosphorylated tau, and total tau were measured at baseline and used for criterion validation.

Results: Practice-effect-adjusted scores increased MCI incidence by 26% (p<.001). Adjustment increased proportions of amyloid-positive MCI cases (+20%) and reduced proportions of amyloid-positive CNs (-6%) (ps<.007). With the increased MCI base rate, adjustment for practice effects would reduce the sample size needed for detecting significant drug treatment effects by an average of 21%, which we demonstrate would result in multi-million-dollar savings in a clinical trial.

Interpretation: Adjusting for practice effects on cognitive testing leads to earlier detection of MCI. When MCI is an outcome, this reduces recruitment needed for clinical trials, study duration, staff and participant burden, and can dramatically lower costs. Importantly, biomarker evidence also indicates improved diagnostic accuracy.
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http://dx.doi.org/10.1101/2020.11.03.20224808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7654904PMC
November 2020

Genetic Variation in the Androgen Receptor Modifies the Association Between Testosterone and Vitality in Middle-Aged Men.

J Sex Med 2020 12 1;17(12):2351-2361. Epub 2020 Oct 1.

Department of Psychiatry, University of California, San Diego, La Jolla, CA; Center for Behavior Genetics of Aging, University of California, San Diego, La Jolla, CA.

Background: Low vitality is a common symptom of testosterone deficiency; however, clinical trial results remain inconclusive regarding the responsiveness of this symptom to hormone replacement.

Aim: The aim of the present study was to determine if the relationship between circulating testosterone levels and vitality would be moderated by the CAG repeat length in the androgen receptor (AR) gene, which influences the receptor's sensitivity to testosterone.

Methods: We examined 676 men in the Vietnam Era Twin Study of Aging when they were, on average, 55.4 years old (SD = 2.5). Salivary testosterone levels were measured by using 3 samples collected at waking on 3 nonconsecutive days. The average testosterone level was classified as low, normal, or high based on 1-SD cutoffs. Analyses were conducted using multilevel, mixed linear models, which accounted for the nonindependence of the twin data, and adjusted for the effects of age, ethnicity, BMI, chronic health conditions, depressive symptoms, and sleep quality.

Outcomes: Vitality was measured using the 36-item Short Form (SF-36) vitality subscale.

Results: We observed a significant interaction between salivary testosterone and the AR-CAG repeat length. When the repeat length was short, men with low testosterone had significantly lower vitality. As the AR-CAG repeat length increased, the magnitude of the testosterone effect decreased.

Clinical Translation: The observed interaction between testosterone and variation in the AR gene suggests that men with more sensitive ARs, as indicated by a shorter AR-CAG repeat, are more likely to experience symptoms of age-related testosterone deficiency.

Strengths & Limitations: Strengths of the present study include our use of a large community-based sample, the use of multiple testosterone measurements, and the availability of a comprehensive set of covariates that may impact the association of interest. Limitations include the homogeneous nature of the sample with respect to ethnicity, the brevity of the 36-item Short Form vitality subscale, and our inability to establish change in testosterone levels because of the cross-sectional nature of data.

Conclusions: The association between testosterone and vitality appears to be clinically meaningful and is in part dependent on variation in the AR gene. Panizzon MS, Bree K, Hsieh T-C, et al. Genetic Variation in the Androgen Receptor Modifies the Association Between Testosterone and Vitality in Middle-Aged Men. J Sex Med 2020;17:2351-2361.
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http://dx.doi.org/10.1016/j.jsxm.2020.08.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7718411PMC
December 2020

Genetic correlations and genome-wide associations of cortical structure in general population samples of 22,824 adults.

Nat Commun 2020 09 22;11(1):4796. Epub 2020 Sep 22.

Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands.

Cortical thickness, surface area and volumes vary with age and cognitive function, and in neurological and psychiatric diseases. Here we report heritability, genetic correlations and genome-wide associations of these cortical measures across the whole cortex, and in 34 anatomically predefined regions. Our discovery sample comprises 22,824 individuals from 20 cohorts within the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium and the UK Biobank. We identify genetic heterogeneity between cortical measures and brain regions, and 160 genome-wide significant associations pointing to wnt/β-catenin, TGF-β and sonic hedgehog pathways. There is enrichment for genes involved in anthropometric traits, hindbrain development, vascular and neurodegenerative disease and psychiatric conditions. These data are a rich resource for studies of the biological mechanisms behind cortical development and aging.
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http://dx.doi.org/10.1038/s41467-020-18367-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7508833PMC
September 2020

Genetic and environmental variation in educational attainment: an individual-based analysis of 28 twin cohorts.

Sci Rep 2020 07 29;10(1):12681. Epub 2020 Jul 29.

Washington State Twin Registry, Washington State University - Health Sciences Spokane, Spokane, WA, USA.

We investigated the heritability of educational attainment and how it differed between birth cohorts and cultural-geographic regions. A classical twin design was applied to pooled data from 28 cohorts representing 16 countries and including 193,518 twins with information on educational attainment at 25 years of age or older. Genetic factors explained the major part of individual differences in educational attainment (heritability: a = 0.43; 0.41-0.44), but also environmental variation shared by co-twins was substantial (c = 0.31; 0.30-0.33). The proportions of educational variation explained by genetic and shared environmental factors did not differ between Europe, North America and Australia, and East Asia. When restricted to twins 30 years or older to confirm finalized education, the heritability was higher in the older cohorts born in 1900-1949 (a = 0.44; 0.41-0.46) than in the later cohorts born in 1950-1989 (a = 0.38; 0.36-0.40), with a corresponding lower influence of common environmental factors (c = 0.31; 0.29-0.33 and c = 0.34; 0.32-0.36, respectively). In conclusion, both genetic and environmental factors shared by co-twins have an important influence on individual differences in educational attainment. The effect of genetic factors on educational attainment has decreased from the cohorts born before to those born after the 1950s.
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http://dx.doi.org/10.1038/s41598-020-69526-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7391756PMC
July 2020

Mutations in FAM50A suggest that Armfield XLID syndrome is a spliceosomopathy.

Nat Commun 2020 07 23;11(1):3698. Epub 2020 Jul 23.

Center for Human Disease Modeling, Duke University Medical Center, Durham, NC, USA.

Intellectual disability (ID) is a heterogeneous clinical entity and includes an excess of males who harbor variants on the X-chromosome (XLID). We report rare FAM50A missense variants in the original Armfield XLID syndrome family localized in Xq28 and four additional unrelated males with overlapping features. Our fam50a knockout (KO) zebrafish model exhibits abnormal neurogenesis and craniofacial patterning, and in vivo complementation assays indicate that the patient-derived variants are hypomorphic. RNA sequencing analysis from fam50a KO zebrafish show dysregulation of the transcriptome, with augmented spliceosome mRNAs and depletion of transcripts involved in neurodevelopment. Zebrafish RNA-seq datasets show a preponderance of 3' alternative splicing events in fam50a KO, suggesting a role in the spliceosome C complex. These data are supported with transcriptomic signatures from cell lines derived from affected individuals and FAM50A protein-protein interaction data. In sum, Armfield XLID syndrome is a spliceosomopathy associated with aberrant mRNA processing during development.
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http://dx.doi.org/10.1038/s41467-020-17452-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7378245PMC
July 2020

Interaction between Alcohol Consumption and Apolipoprotein E (ApoE) Genotype with Cognition in Middle-Aged Men.

J Int Neuropsychol Soc 2021 01 14;27(1):56-68. Epub 2020 Jul 14.

Department of Psychiatry, University of California San Diego, La Jolla, CA, USA.

Objective: Heavy alcohol consumption is associated with poorer cognitive function in older adults. Although understudied in middle-aged adults, the relationship between alcohol and cognition may also be influenced by genetics such as the apolipoprotein (ApoE) ε4 allele, a risk factor for Alzheimer's disease. We examined the relationship between alcohol consumption, ApoE genotype, and cognition in middle-aged adults and hypothesized that light and/or moderate drinkers (≤2 drinks per day) would show better cognitive performance than heavy drinkers or non-drinkers. Additionally, we hypothesized that the association between alcohol use and cognitive function would differ by ApoE genotype (ε4+ vs. ε4-).

Method: Participants were 1266 men from the Vietnam Era Twin Study of Aging (VETSA; M age = 56; range 51-60) who completed a neuropsychological battery assessing seven cognitive abilities: general cognitive ability (GCA), episodic memory, processing speed, executive function, abstract reasoning, verbal fluency, and visuospatial ability. Alcohol consumption was categorized into five groups: never, former, light, moderate, and heavy.

Results: In fully adjusted models, there was no significant main effect of alcohol consumption on cognitive functions. However, there was a significant interaction between alcohol consumption and ApoE ε4 status for GCA and episodic memory, such that the relationship of alcohol consumption and cognition was stronger in ε4 carriers. The ε4+ heavy drinking subgroup had the poorest GCA and episodic memory.

Conclusions: Presence of the ε4 allele may increase vulnerability to the deleterious effects of heavy alcohol consumption. Beneficial effects of light or moderate alcohol consumption were not observed.
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http://dx.doi.org/10.1017/S1355617720000570DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7856052PMC
January 2021

Association of baseline semantic fluency and progression to mild cognitive impairment in middle-aged men.

Neurology 2020 08 30;95(8):e973-e983. Epub 2020 Jun 30.

From the Department of Psychiatry (A.J.J.), Center for Behavior Genetics of Aging (D.E.G., J.A.E., M.S.P., C.E.F., J.Z., M.S.-C., W.S.K.), University of California, San Diego, La Jolla; Department of Medicine (D.E.G.), Vanderbilt University Medical Center, Nashville, TN; Department of Psychology (M.S.-C.), San Diego State University; Department of Psychology (C.A.R.), University of California; Department of Psychiatry and Behavioral Neuroscience (K.C.J.), University of Chicago, IL; Department of Epidemiology and Biostatistics (H.X.), St. Louis University; Clinical Epidemiology Center (H.X.), Veterans Affairs St. Louis Healthcare System, MO; Psychology Service (A.J.J.) and Center of Excellence for Stress and Mental Health (A.J.J., W.S.K.), Veterans Affairs San Diego Healthcare System, CA; and Department of Psychological and Brain Sciences (R.T., M.J.L.), Boston University, MA.

Objective: To test the hypothesis that individual differences in episodic memory and verbal fluency in cognitively normal middle-aged adults will predict progression to amnestic mild cognitive impairment (MCI) after 6 years.

Method: The cohort analyzed included 842 male twins who were cognitively normal at baseline (mean 56 years) and completed measures of episodic memory and verbal fluency at baseline and again 6 years later (mean 62 years).

Results: Poor episodic memory predicted progression to both amnestic MCI (odds ratio [OR], 4.42; 95% confidence interval [CI], 2.44-10.60) and nonamnestic MCI (OR, 1.92; 95% CI, 1.32-3.44). Poor semantic verbal fluency also independently predicted progression to amnestic MCI (OR, 1.86; 95% CI, 1.12-3.52). In the full sample, a semantic-specific fluency latent variable at wave 1 (which controls for letter fluency) predicted change in episodic memory at wave 2 (β = 0.13), but not vice versa (β = 0.04). Associations between episodic memory and verbal fluency factors were primarily explained by genetic, rather than environmental, correlations.

Conclusions: Among individuals who were cognitively normal at wave 1, episodic memory moderately to strongly predicted progression to MCI at average age 62, emphasizing the fact that there is still meaningful variability even among cognitively normal individuals. Episodic memory, which is typically a primary focus for Alzheimer disease (AD) risk, declined earlier and more quickly than fluency. However, semantic fluency at average age 56 predicted 6-year change in memory as well as progression to amnestic MCI even after accounting for baseline memory performance. These findings emphasize the utility of memory and fluency measures in early identification of AD risk.
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http://dx.doi.org/10.1212/WNL.0000000000010130DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7668546PMC
August 2020

Predicting Health-Related Quality of Life in Trauma-Exposed Male Veterans in Late Midlife: A 20 Year Longitudinal Study.

Int J Environ Res Public Health 2020 06 24;17(12). Epub 2020 Jun 24.

Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA.

Trauma-exposed adults with high levels of posttraumatic stress symptoms (PTSS) report poorer health-related quality of life (HRQOL), but less is known about the persistence of this relationship over time. Participants from the Vietnam Era Twin Study of Aging reported on PTSS, health, and sociodemographic characteristics at average age 38; 775 participants reported having been exposed to trauma. Later, at average ages 56 and 62, mental and physical HRQOL were assessed with the Short-Form 36. Premorbid risk for anxiety/neuroticism was evaluated with a polygenic risk score derived from a large genome-wide association study meta-analysis. In multivariate mixed models, having higher levels of PTSS, poorer self-rated health, lower income, and less education at age 38 were associated with worse physical and mental HRQOL two decades later. Chronic health problems at age 38 predicted midlife physical but not mental HRQOL. Although genetic risk for neuroticism was correlated with HRQOL and PTSS, it was no longer significant in multivariate models. Health-related quality of life (HRQOL) predicts morbidity and mortality independently of objective health measures; early interventions may help to mitigate the ongoing impact of trauma on quality of life.
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http://dx.doi.org/10.3390/ijerph17124554DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7345107PMC
June 2020

Genetic Underpinnings of Increased BMI and Its Association With Late Midlife Cognitive Abilities.

Gerontol Geriatr Med 2020 Jan-Dec;6:2333721420925267. Epub 2020 Jun 1.

University of California San Diego, La Jolla, CA, USA.

First, we test for differences in various cognitive abilities across trajectories of body mass index (BMI) over the later life course. Second, we examine whether genetic risk factors for unhealthy BMIs-assessed via polygenic risk scores (PRS)-predict cognitive abilities in late-life. The study used a longitudinal sample of Vietnam veteran males to explore the associations between BMI trajectories, measured across four time points, and later cognitive abilities. The sample of 977 individuals was drawn from the Vietnam Era Twin Study of Aging. Cognitive abilities evaluated included executive function, abstract reasoning, episodic memory, processing speed, verbal fluency, and visual spatial ability. Multilevel linear regression models were used to estimate the associations between BMI trajectories and cognitive abilities. Then, BMI PRS was added to the models to evaluate polygenic associations with cognitive abilities. There were no significant differences in cognitive ability between any of the BMI trajectory groups. There was a significant inverse relationship between BMI-PRS and several cognitive ability measures. While no associations emerged for BMI trajectories and cognitive abilities at the phenotypic levels, BMI PRS measures did correlate with key cognitive domains. Our results suggest possible polygenic linkages cutting across key components of the central and peripheral nervous system.
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http://dx.doi.org/10.1177/2333721420925267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7268925PMC
June 2020

Genetic and environmental influences on human height from infancy through adulthood at different levels of parental education.

Sci Rep 2020 05 14;10(1):7974. Epub 2020 May 14.

Department of Epidemiology, School of Public Health, Seoul National University, Seoul, 08826, Korea.

Genetic factors explain a major proportion of human height variation, but differences in mean stature have also been found between socio-economic categories suggesting a possible effect of environment. By utilizing a classical twin design which allows decomposing the variation of height into genetic and environmental components, we tested the hypothesis that environmental variation in height is greater in offspring of lower educated parents. Twin data from 29 cohorts including 65,978 complete twin pairs with information on height at ages 1 to 69 years and on parental education were pooled allowing the analyses at different ages and in three geographic-cultural regions (Europe, North America and Australia, and East Asia). Parental education mostly showed a positive association with offspring height, with significant associations in mid-childhood and from adolescence onwards. In variance decomposition modeling, the genetic and environmental variance components of height did not show a consistent relation to parental education. A random-effects meta-regression analysis of the aggregate-level data showed a trend towards greater shared environmental variation of height in low parental education families. In conclusion, in our very large dataset from twin cohorts around the globe, these results provide only weak evidence for the study hypothesis.
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http://dx.doi.org/10.1038/s41598-020-64883-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7224277PMC
May 2020

Extensive memory testing improves prediction of progression to MCI in late middle age.

Alzheimers Dement (Amst) 2020 11;12(1):e12004. Epub 2020 Apr 11.

Department of Psychiatry Center for Behavior Genetics of Aging University of California San Diego La Jolla California.

Introduction: Predicting risk for Alzheimer's disease when most people are likely still biomarker negative would aid earlier identification. We hypothesized that combining multiple memory tests and scores in middle-aged adults would provide useful, and non-invasive, prediction of 6-year progression to MCI.

Methods: We examined 849 men who were cognitively normal at baseline (mean age ± SD = 55.69 ± 2.45).

Results: California Verbal Learning Test learning trials was the best individual predictor of amnestic MCI (OR = 4.75). A latent factor incorporating seven measures across three memory tests provided much stronger prediction (OR = 9.88). This compared favorably with biomarker-based prediction in a study of much older adults.

Discussion: Neuropsychological tests are sensitive and early indicators of MCI risk at an age when few individuals are likely to have yet become biomarker positive. The single best measures may appear time- and cost-effective, but 30 additional minutes of testing and use of multiple scores within tests provide substantially improved prediction.
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http://dx.doi.org/10.1002/dad2.12004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7148418PMC
April 2020

Amyloid-β Positivity Predicts Cognitive Decline but Cognition Predicts Progression to Amyloid-β Positivity.

Biol Psychiatry 2020 05 7;87(9):819-828. Epub 2020 Jan 7.

Department of Psychiatry, University of California, San Diego, California; Center for Behavior Genetics of Aging, University of California, San Diego, California; Center of Excellence for Stress and Mental Health, VA San Diego Healthcare System, La Jolla, California.

Background: Stage 1 of the National Institute on Aging-Alzheimer's Association's proposed Alzheimer's disease continuum is defined as amyloid-β (Aβ) positive but cognitively normal. Identifying at-risk individuals before Aβ reaches pathological levels could have great benefits for early intervention. Although Aβ levels become abnormal long before severe cognitive impairments appear, increasing evidence suggests that subtle cognitive changes may begin early, potentially before Aβ surpasses the threshold for abnormality. We examined whether baseline cognitive performance would predict progression from normal to abnormal levels of Aβ.

Methods: We examined the association of baseline cognitive composites (Preclinical Alzheimer Cognitive Composite, Alzheimer's Disease Neuroimaging Initiative (ADNI) memory factor composite) with progression to Aβ positivity in 292 nondemented, Aβ-negative ADNI participants. Additional analyses included continuous cerebrospinal fluid biomarker levels to examine the effects of subthreshold pathology.

Results: Forty participants progressed to Aβ positivity during follow-up. Poorer baseline performance on both cognitive measures was significantly associated with increased odds of progression. More abnormal levels of baseline cerebrospinal fluid phosphorylated tau and subthreshold Aβ were associated with increased odds of progression to Aβ positivity. Nevertheless, baseline ADNI memory factor composite performance predicted progression even after controlling for baseline biomarker levels and APOE genotype (Preclinical Alzheimer Cognitive Composite was trend level). Survival analyses were largely consistent: controlling for baseline biomarker levels, baseline Preclinical Alzheimer Cognitive Composite still significantly predicted progression time to Aβ positivity (ADNI memory factor composite was trend level).

Conclusions: The possibility of intervening before Aβ reaches pathological levels is of obvious benefit. Low-cost, noninvasive cognitive measures can be informative for determining who is likely to progress to Aβ positivity, even after accounting for baseline subthreshold biomarker levels.
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http://dx.doi.org/10.1016/j.biopsych.2019.12.021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7166153PMC
May 2020

Current Status of the Vietnam Era Twin Study of Aging (VETSA).

Twin Res Hum Genet 2019 12 14;22(6):783-787. Epub 2020 Jan 14.

Department of Psychological & Brain Science, Boston University, Boston, MA, USA.

The Vietnam Era Twin Study of Aging (VETSA) is a longitudinal behavioral genetic study with a primary focus on cognitive and brain aging in men, particularly early identification of risk for mild cognitive impairment (MCI) and Alzheimer's disease (AD). It comprises a subset of over 1600 twins from the Vietnam Era Twin Registry. Twins live all over the USA. Assessments began when participants were in their 50s. Follow-ups were conducted every 5-6 years, and wave 3 has been completed as of this writing. The age range of participants is narrow (about 10 years). An extensive neurocognitive test battery has added precision in assessing differences in middle-aged adults, and predicting progression to MCI. Young adult cognitive test data (at an average age of 20 years) provide a means of disentangling aging effects from longstanding differences. Genome wide genotyping and plasma assays of AD biomarkers from waves 1 and 3 were conducted in wave 3. These features make the VETSA ideal for studying the heterogeneity of within-individual trajectories from midlife to old age, and for early detection of risk factors for cognitive decline.
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http://dx.doi.org/10.1017/thg.2019.125DOI Listing
December 2019
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