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1.
Neurobiol Aging ; 84: 17-25, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31479860

RESUMO

The associations of 4 proteins-AK4, ITPK1, HSPB2, and IGFBP5-with cognitive function in older adults were largely unexplained by known brain pathologies. We examined the extent to which individual protein associations with cognitive decline were attributable to microstructural changes in the brain. This study included 521 participants (mean age 90.3, 65.9-108.3) with the postmortem reciprocal of transverse relaxation time (R2) magnetic resonance image. All participants came from one of the 2 ongoing longitudinal cohorts of aging and dementia, the Religious Orders Study and Rush Memory and Aging Project. Higher abundance of AK4, HSPB2, and IGFBP5 was associated with faster cognitive decline and mediated through lower postmortem R2 in the frontal and temporal white matter regions. In contrast, higher abundance of ITPK1 was associated with slower cognitive decline and mediated through higher postmortem R2 in the frontal and temporal white matter regions. The associations of 4 proteins-AK4, ITPK1, IGFBP5, and HSPB2-with cognition in late life were explained via microstructural changes in the brain.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31513029

RESUMO

OBJECTIVE: A rare variant in TREM2 (p.R47H, rs75932628) has been consistently reported to increase the risk for Alzheimer disease (AD), while mixed evidence has been reported for association of the variant with other neurodegenerative diseases. Here, we investigated the frequency of the R47H variant in a diverse and well-characterized multicenter neurodegenerative disease cohort. METHODS: We examined the frequency of the R47H variant in a diverse neurodegenerative disease cohort, including a total of 3058 patients clinically diagnosed with AD, frontotemporal dementia spectrum syndromes, mild cognitive impairment, progressive supranuclear palsy syndrome, corticobasal syndrome, or amyotrophic lateral sclerosis and 5089 control subjects. RESULTS: We observed a significant association between the R47H variant and AD, while no association was observed with any other neurodegenerative disease included in this study. CONCLUSIONS: Our results support the consensus that the R47H variant is significantly associated with AD. However, we did not find evidence for association of the R47H variant with other neurodegenerative diseases.

3.
J Hypertens ; 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31503136

RESUMO

OBJECTIVES: Decision making, key to successful aging, has implications for financial success, physical health, and well being. While poor decision making has been linked with increased risk of mortality, age-related cognitive decline, and dementia, less is known regarding its associations with chronic disease indicators. We investigated the associations of decision making with blood pressure (BP) values [i.e., SBP, mean arterial pressure (MAP), and pulse pressure (PP), separately] in a community-based cohort study of aging. METHODS: Participants were 908 nondemented older adults (age ∼81 years; 75% women) from the Rush Memory and Aging Project. Decision making was measured using questions designed to simulate materials used in financial and healthcare settings in the real world and yielded a total score and domain-specific health and financial decision making scores. Two seated and one standing BP measurement were taken with all three contributing to average SBP, MAP that is, [SBP + (2 × DBP)]/3, and PP, that is, SBP - DBP. Participants were queried about hypertension status and antihypertension medications were visually inspected and coded. Participants also underwent medical history and cognitive assessments. RESULTS: In separate multivariable linear regression models, total decision making scores were inversely associated with SBP, MAP, and PP after adjusting for age, sex, education, antihypertension medication use, diabetes, and cumulative cardiovascular disease burden (P values = 0.03). Decision making remained associated with these BP values after additional adjustment for global cognition. CONCLUSION: Poorer decision making is associated with higher BP values in nondemented older adults.

4.
Brain ; 142(9): 2581-2589, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31497858

RESUMO

Autopsy measures of Alzheimer's disease neuropathology have been leveraged as endophenotypes in previous genome-wide association studies (GWAS). However, despite evidence of sex differences in Alzheimer's disease risk, sex-stratified models have not been incorporated into previous GWAS analyses. We looked for sex-specific genetic associations with Alzheimer's disease endophenotypes from six brain bank data repositories. The pooled dataset included 2701 males and 3275 females, the majority of whom were diagnosed with Alzheimer's disease at autopsy (70%). Sex-stratified GWAS were performed within each dataset and then meta-analysed. Loci that reached genome-wide significance (P < 5 × 10-8) in stratified models were further assessed for sex interactions. Additional analyses were performed in independent datasets leveraging cognitive, neuroimaging and CSF endophenotypes, along with age-at-onset data. Outside of the APOE region, one locus on chromosome 7 (rs34331204) showed a sex-specific association with neurofibrillary tangles among males (P = 2.5 × 10-8) but not females (P = 0.85, sex-interaction P = 2.9 × 10-4). In follow-up analyses, rs34331204 was also associated with hippocampal volume, executive function, and age-at-onset only among males. These results implicate a novel locus that confers male-specific protection from tau pathology and highlight the value of assessing genetic associations in a sex-specific manner.

5.
Cell Rep ; 28(7): 1799-1813.e5, 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31412248

RESUMO

The Alzheimer's disease (AD) susceptibility gene, CD2-associated protein (CD2AP), encodes an actin binding adaptor protein, but its function in the nervous system is largely unknown. Loss of the Drosophila ortholog cindr enhances neurotoxicity of human Tau, which forms neurofibrillary tangle pathology in AD. We show that Cindr is expressed in neurons and present at synaptic terminals. cindr mutants show impairments in synapse maturation and both synaptic vesicle recycling and release. Cindr associates and genetically interacts with 14-3-3ζ, regulates the ubiquitin-proteasome system, and affects turnover of Synapsin and the plasma membrane calcium ATPase (PMCA). Loss of cindr elevates PMCA levels and reduces cytosolic calcium. Studies of Cd2ap null mice support a conserved role in synaptic proteostasis, and CD2AP protein levels are inversely related to Synapsin abundance in human postmortem brains. Our results reveal CD2AP neuronal requirements with relevance to AD susceptibility, including for proteostasis, calcium handling, and synaptic structure and function.

6.
Alzheimers Dement ; 2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31420203

RESUMO

INTRODUCTION: We classified individuals based on their baseline performance on cognitive measures and investigated the association between cognitive classifications and neuropathological findings ∼7 years later, as an external validator. METHODS: Brain autopsies of 779 decedents were examined. Baseline latent class analysis on 10 neuropsychological measures was previously assigned: mixed-domains impairment (n = 39, 5%), memory-specific impairment (n = 210, 27%), frontal impairment (n = 113, 14.5%), average cognition (n = 360, 46.2%), and superior cognition (n = 57, 7.3%). Linear regressions and risks ratios were used to examine the relation of latent class assignment at enrollment with neuropathological indices. RESULTS: Amyloid ß, tau, and transactive response DNA-binding protein 43 were associated with mixed-domains impairment and memory-specific impairment classes ∼7 years before death. Moderate arteriolosclerosis was associated with membership in the frontal impairment class. DISCUSSION: Our findings support the use of latent class models that incorporate more comprehensive neuropsychological measures to classify cognitive impairment.

7.
PLoS One ; 14(8): e0220968, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31404102

RESUMO

Alzheimer's disease and related disorders (ADRD) may manifest cognitive and non-cognitive phenotypes including motor impairment, suggesting a shared underlying biology. We tested the hypothesis that five cortical proteins identified from a gene network that drives AD and cognitive phenotypes are also related to motor function in the same individuals. We examined 1208 brains of older adults with motor and cognitive assessments prior to death. Cortical proteins were quantified with SRM proteomics and we collected indices of AD and other related pathologies. A higher level of IGFBP5 was associated with poorer motor function proximate to death but AK4, HSPB2, ITPK1 and PLXNB1 were unrelated to motor function. The association of IGFBP5 with motor function was unrelated to the presence of indices of brain pathologies. In contrast, the addition of a term for cognition attenuated the association of IGFBP5 with motor function by about 90% and they were no longer related. These data lend support for the idea that unidentified cortical proteins like IGFBP5, which may not manifest a known pathologic footprint, may contribute to motor and cognitive function in older adults.

8.
Am J Hum Genet ; 105(3): 562-572, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31447098

RESUMO

Deciphering the environmental contexts at which genetic effects are most prominent is central for making full use of GWAS results in follow-up experiment design and treatment development. However, measuring a large number of environmental factors at high granularity might not always be feasible. Instead, here we propose extracting cellular embedding of environmental factors from gene expression data by using latent variable (LV) analysis and taking these LVs as environmental proxies in detecting gene-by-environment (GxE) interaction effects on gene expression, i.e., GxE expression quantitative trait loci (eQTLs). Applying this approach to two largest brain eQTL datasets (n = 1,100), we show that LVs and GxE eQTLs in one dataset replicate well in the other dataset. Combining the two samples via meta-analysis, 895 GxE eQTLs are identified. On average, GxE effect explains an additional ∼4% variation in expression of each gene that displays a GxE effect. Ten of these 52 genes are associated with cell-type-specific eQTLs, and the remaining genes are multi-functional. Furthermore, after substituting LVs with expression of transcription factors (TF), we found 91 TF-specific eQTLs, which demonstrates an important use of our brain GxE eQTLs.

9.
Artigo em Inglês | MEDLINE | ID: mdl-31272924

RESUMO

INTRODUCTION: Mobility metrics derived from wearable sensor recordings are associated with parkinsonism in older adults. We examined if these metrics predict incident parkinsonism. METHODS: Parkinsonism was assessed annually in 683 ambulatory, community-dwelling older adults without parkinsonism at baseline. Four parkinsonian signs were derived from a modified Unified Parkinson's Disease Rating Scale (UPDRS). Parkinsonism was based on the presence of 2 or more signs. Participants wore a sensor on their back while performing a 32 foot walk, standing posture, and Timed Up and Go (TUG) tasks. 12 mobility scores were extracted. Cox proportional hazards models with backward elimination were used to identify combinations of mobility scores independently associated with incident parkinsonism. RESULTS: During follow-up of 2.5 years (SD = 1.28), 139 individuals developed parkinsonism (20.4%). In separate models, 6 of 12 mobility scores were individually associated with incident parkinsonism, including: Speed and Regularity (from 32 ft walk), Sway (from standing posture), and 3 scores from TUG subtasks (Posterior sit to stand transition, Range stand to sit transition, and Yaw, a measure of turning efficiency). When all mobility scores were analyzed together in a single model, 2 TUG subtask scores, Range from stand to sit transition (HR, 1.42, 95%CI, 1.09, 1.82) and Yaw from turning (HR, 0.56, 95%CI, 0.42, 0.73) were independently associated with incident parkinsonism. These results were unchanged when controlling for chronic health covariates. CONCLUSION: Mobility metrics derived from a wearable sensor complement conventional gait testing and have potential to enhance risk stratification of older adults who may develop parkinsonism.

10.
J Alzheimers Dis ; 70(2): 611-619, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31256124

RESUMO

BACKGROUND: There is considerable heterogeneity in clinical presentation among people with late-onset Alzheimer's disease (LOAD). We have categorized people with LOAD into subgroups based on relative impairments across cognitive domains. These 6 groups are people with no relatively impaired domains (AD-No Domains), 4 groups with one relatively impaired domain (AD-Memory, AD-Executive, AD-Language, and AD-Visuospatial), and a group with multiple relatively impaired domains (AD-Multiple Domains). Our previous analysis demonstrated that genetic factors vary across cognitively-defined LOAD groups. OBJECTIVE: To determine whether risks associated with depression and traumatic brain injury with loss of consciousness (TBI) for cognitively defined LOAD subgroups are similar. METHODS: We used cognitive data at LOAD diagnosis from three prospective cohort studies to determine cognitively-defined subgroups. We compared subgroups in endorsement of items from the Centers for Epidemiological Studies Depression (CES-D) scale and history of TBI. RESULTS: Among 1,505 people with LOAD from the three studies, there were substantial differences across subgroups in total CES-D score, with lower scores (less depression) for people with AD with relative impairments in memory (AD-Memory) compared to those in other groups. Differences were noteworthy for the sleep-related item of the CES-D, as people with AD-Memory were less likely to report restless sleep than people in other groups. There were no differences in TBI history across groups. CONCLUSIONS: Differences in risk factor associations across subgroups such as differences in endorsement of depression symptoms and restless sleep provide support for the hypothesis that there are biologically coherent subgroups of AD.

11.
Aging Clin Exp Res ; 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31273677

RESUMO

BACKGROUND: Health and financial literacy are central to older adults' well-being and financial standing, but the relation of literacy with mortality in advanced age remains unclear. AIMS: To determine whether lower literacy, as reflected in measures of total literacy and subscales of health and financial literacy, was associated with an increased risk of mortality. METHODS: Participants were 931 community-based older adults from the Rush Memory and Aging Project [age: mean (SD) = 80.9 (7.6), range 58.8-100.8], an ongoing, prospective observational cohort study of aging. Participants were without dementia at the time literacy was assessed. Proportional hazards models were used to determine whether literacy measures were associated with mortality. RESULTS: During up to 8 years of follow-up, 224 (24.1% of 931) participants died. In models that adjusted for age, sex, and education, lower total, health, and financial literacy were each associated with an increased risk of mortality (total literacy: HR = 1.020, 95% CI 1.010-1.031, p < 0.001; health literacy: HR = 1.015, 95% CI 1.008-1.023, p < 0.001; financial literacy: HR = 1.013, 95% CI 1.003-1.023, p = 0.014). These associations persisted after additionally adjusting for income and indices of health status; however, only the association of lower health literacy with mortality persisted after further adjusting for a robust measure of global cognition. DISCUSSION: We suspect that the current associations of lower literacy with mortality reflect the detrimental effect of early pathologic brain aging on literacy. CONCLUSIONS: Lower literacy, particularly lower health literacy, is associated with mortality in advanced age.

12.
JAMA Neurol ; 2019 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-31302677

RESUMO

Importance: Evidence on the association of lifespan cognitive reserve (CR) with dementia is limited, and the strength of this association in the presence of brain pathologies is unknown. Objective: To examine the association of lifespan CR with dementia risk, taking brain pathologies into account. Design, Setting, and Participants: This study used data from 2022 participants in the Rush Memory and Aging Project, an ongoing community-based cohort study with annual follow-up from 1997 to 2018 (mean follow-up, 6 years; maximum follow-up, 20 years). After excluding 420 individuals who had prevalent dementia, missing data on CR, or dropped out, 1602 dementia-free adults were identified at baseline and evaluated to detect incident dementia. During follow-up, 611 died and underwent autopsies. Data were analyzed from May to September 2018. Exposures: Information on CR factors (education; early-life, midlife, and late-life cognitive activities; and social activities in late life) was obtained at baseline. Based on these factors, lifespan CR scores were captured using a latent variable from a structural equation model and was divided into tertiles (lowest, middle, and highest). Main Outcomes and Measures: Dementia was diagnosed following international criteria. Neuropathologic evaluations for Alzheimer disease and other brain pathologies were performed in autopsied participants. The association of lifespan CR with dementia or brain pathologies was estimated using Cox regression models or logistic regression. Results: Of the 1602 included participants, 1216 (75.9%) were women, and the mean (SD) age was 79.6 (7.5) years. During follow-up, 386 participants developed dementia (24.1%), including 357 participants with Alzheimer disease-related dementia (22.3%). The multiadjusted hazards ratios (HRs) of dementia were 0.77 (95% CI, 0.59-0.99) for participants in the middle CR score tertile and 0.61 (95% CI, 0.47-0.81) for those in the highest CR score tertile compared with those in the lowest CR score tertile. In autopsied participants, CR was not associated with most brain pathologies, and the association of CR with dementia remained significant after additional adjustment for brain pathologies (HR, 0.60; 95% CI, 0.42-0.86). The highest CR score tertile was associated with a reduction in dementia risk, even among participants with high Alzheimer disease pathology (HR, 0.57; 95% CI, 0.37-0.87) and any gross infarcts (HR, 0.34; 95% CI, 0.18-0.62). Conclusions and Relevance: High lifespan CR is associated with a reduction in dementia risk, even in the presence of high brain pathologies. Our findings highlight the importance of lifespan CR accumulation in dementia prevention.

13.
Artigo em Inglês | MEDLINE | ID: mdl-31305319

RESUMO

BACKGROUND: Low health and financial literacy may be an early behavioral manifestation of cognitive impairment, dementia, and accumulating Alzheimer pathology. However, there are limited studies investigating the behavioral features associated with hyperphosphorylated transactive response DNA-binding protein-43 (TDP-43), a common age-related pathology, and even fewer studies investigating the neurobiological basis underlying low literacy in aging. OBJECTIVE: To test the hypothesis that TDP-43 pathology is associated with lower literacy. MATERIALS AND METHODS: Data came from 293 community-based older persons who were enrolled in 2 ongoing studies of aging. Participants completed literacy and cognitive assessments, consented to brain donation, and underwent detailed neuropathologic evaluation for Alzheimer disease (AD) and TDP-43. Linear regression models assessed the association of TDP-43 with literacy after adjusting for demographics, and AD pathology. Posthoc pairwise comparisons examined whether the level of literacy differed by TDP-43 stage. RESULTS: TDP-43 pathology was associated with lower literacy (estimate=-3.16; SE=0.86; P<0.001), above and beyond demographics and AD pathology, and this association persisted even after additionally adjusting for global cognition (estimate=-1.53; SE=0.74; P=0.038). Further, literacy was lower among persons with neocortical TDP-43 pathology compared with those without TDP-43 pathology. CONCLUSIONS: TDP-43 pathology is associated with lower health and financial literacy in old age, above and beyond AD pathology.

14.
Acta Neuropathol Commun ; 7(1): 104, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31269985

RESUMO

Age is the most robust risk factor for Alzheimer's dementia, however there is little data on the relation of age to Alzheimer's disease (AD) and other common neuropathologies that contribute to Alzheimer's dementia. We use data from two community-based, clinical-pathologic cohorts to examine the association of age with AD and other common pathologies. Participants were 1420 autopsied individuals from the Religious Orders Study or Rush Memory and Aging Project who underwent annual clinical evaluations for diagnosis of Alzheimer's dementia, mild cognitive impairment (MCI), and level of cognition. The neuropathologic traits of interest were pathologic AD according to modified NIA-Reagan criteria, three quantitative measures of AD pathology (global AD pathology score, ß-amyloid load and PHFtau tangle density), macro- and micro-scopic infarcts, neocortical Lewy bodies, TDP-43 and hippocampal sclerosis. Semiparametric generalized additive models examined the nonlinear relationship between age and the clinical and pathological outcomes. The probability of Alzheimer's dementia at death increased with age such that for every additional year of age, the log odds of Alzheimer's dementia was 0.067 higher, corresponding to an odds ratio of 1.070 (p < 0.001). Results were similar for cognitive impairment and level of cognition. By contrast, a nonlinear relationship of age with multiple indices of AD pathology was observed (all ps < 0.05), such that pathologic AD reached a peak around 95 years of age and leveled off afterwards; the quantitative measures of AD pathology were significantly lower at ages above 95. The association of age with other neuropathologies was quite distinct from that of AD in that most increased with advancing age. AD pathology appears to peak around 95 years of age while other common pathologies continue to increase with age.

15.
Cell Rep ; 28(4): 1103-1116.e4, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31340147

RESUMO

Asymptomatic and symptomatic Alzheimer's disease (AD) subjects may present with equivalent neuropathological burdens but have significantly different antemortem cognitive decline rates. Using the transcriptome as a proxy for functional state, we selected 414 expression profiles of symptomatic AD subjects and age-matched non-demented controls from a community-based neuropathological study. By combining brain tissue-specific protein interactomes with gene networks, we identified functionally distinct composite clusters of genes that reveal extensive changes in expression levels in AD. Global expression for clusters broadly corresponding to synaptic transmission, metabolism, cell cycle, survival, and immune response were downregulated, while the upregulated cluster included largely uncharacterized processes. We propose that loss of EGR3 regulation mediates synaptic deficits by targeting the synaptic vesicle cycle. Our results highlight the utility of integrating protein interactions with gene perturbations to generate a comprehensive framework for characterizing alterations in the molecular network as applied to AD.

16.
Mol Psychiatry ; 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31332262

RESUMO

Vascular endothelial growth factor (VEGF) is associated with the clinical manifestation of Alzheimer's disease (AD). However, the role of the VEGF gene family in neuroprotection is complex due to the number of biological pathways they regulate. This study explored associations between brain expression of VEGF genes with cognitive performance and AD pathology. Genetic, cognitive, and neuropathology data were acquired from the Religious Orders Study and Rush Memory and Aging Project. Expression of ten VEGF ligand and receptor genes was quantified using RNA sequencing of prefrontal cortex tissue. Global cognitive composite scores were calculated from 17 neuropsychological tests. ß-amyloid and tau burden were measured at autopsy. Participants (n = 531) included individuals with normal cognition (n = 180), mild cognitive impairment (n = 148), or AD dementia (n = 203). Mean age at death was 89 years and 37% were male. Higher prefrontal cortex expression of VEGFB, FLT4, FLT1, and PGF was associated with worse cognitive trajectories (p ≤ 0.01). Increased expression of VEGFB and FLT4 was also associated with lower cognition scores at the last visit before death (p ≤ 0.01). VEGFB, FLT4, and FLT1 were upregulated among AD dementia compared with normal cognition participants (p ≤ 0.03). All four genes associated with cognition related to elevated ß-amyloid (p ≤ 0.01) and/or tau burden (p ≤ 0.03). VEGF ligand and receptor genes, specifically genes relevant to FLT4 and FLT1 receptor signaling, are associated with cognition, longitudinal cognitive decline, and AD neuropathology. Future work should confirm these observations at the protein level to better understand how changes in VEGF transcription and translation relate to neurodegenerative disease.

17.
Neuropsychology ; 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31204814

RESUMO

OBJECTIVE: Greater financial and health literacy are associated with better cognition; however, research suggests that some individuals exhibit differences, or discrepancies, in these abilities in old age. We investigated discrepancies between literacy and cognition and factors associated with such discrepancies in older adults without dementia. METHOD: Participants (N = 714; Mage = 81.4; education: M = 15.4; 75.4% female; 5.2% non-White) from the Rush Memory and Aging Project completed cognitive assessments and a financial and health literacy measure that yielded a total literacy score. Participants were characterized into three groups: (a) total literacy scores that are more than one standard deviation (1 SD) above cognition (L > C), (b) total literacy scores falling more than 1 SD below cognition (L < C), and (c) total literacy within 1 SD of cognition (L = C). Logistic regressions were employed to investigate associations between demographic and psychosocial variables and discrepancy group status. RESULTS: Of the 714 participants, 24% showed significant discrepancies. In fully adjusted models, in reference to the L = C group, male sex was associated with greater odds of being in the L > C group (odds ratio [OR] = 2.32, 95% CI [1.33, 4.03], p = .003) and lower odds of being in the L < C group (OR = 0.31, 95% CI [0.14, 0.66], p = .002), higher income was associated with lower odds of being in either discrepancy group (L < C OR = 0.87, 95% CI [0.79, 0.96], p = .004; L > C OR = 0.86, 95% CI [0.76, 0.96], p = .007), and higher trust was associated with lower odds of being in the L > C group (OR = 0.92, 95% CI [0.85, 0.99], p = .030). CONCLUSIONS: Findings support literacy and cognition as partially dissociable constructs and highlight important factors associated with discrepancies between literacy and cognition. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

18.
Artigo em Inglês | MEDLINE | ID: mdl-31246244

RESUMO

BACKGROUND: Gait speed is a robust non-specific predictor of health outcomes. We examined if combinations of gait speed and other mobility metrics are associated with specific health outcomes. METHODS: A sensor (triaxial accelerometer and gyroscope) placed on the lower-back, measured mobility in the homes of 1249 older adults (77% female; 80.0, SD=7.72 years). Twelve gait scores were extracted from 5 performances including: a) walking, b) transition from sit to stand, c) transition from stand to sit, d) turning, and e) standing posture. Using separate Cox proportional hazards models, we examined which metrics were associated with time to mortality, incident ADL disability (ADL), mobility disability mild cognitive impairment (MCI) and Alzheimer's disease (AD) dementia. We employed a single integrated analytic framework to determine which gait scores survived to predict each outcome. RESULTS: During 3.6 years of follow-up, 10 of the 12 gait scores predicted one or more of the five health outcomes. In further analyses, different combinations of 2-3 gait scores survived backward elimination and were associated with the five outcomes. Sway was one of three scores which predicted ADL disability, but was not included in the final models for other outcomes. Gait speed was included along with other metrics in the final models predicting mortality and ADL disability but not for other outcomes. CONCLUSIONS: When analyzing multiple mobility metrics together, different combinations of mobility metrics are related to specific adverse health outcomes. Digital technology enhances our understanding of impaired mobility and may provide mobility biomarkers that predict distinct health outcomes.

19.
JAMA Neurol ; 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31180460

RESUMO

Importance: Previous genome-wide association studies of common variants identified associations for Alzheimer disease (AD) loci evident only among individuals with particular APOE alleles. Objective: To identify APOE genotype-dependent associations with infrequent and rare variants using whole-exome sequencing. Design, Setting, and Participants: The discovery stage included 10 441 non-Hispanic white participants in the Alzheimer Disease Sequencing Project. Replication was sought in 2 independent, whole-exome sequencing data sets (1766 patients with AD, 2906 without AD [controls]) and a chip-based genotype imputation data set (8728 patients with AD, 9808 controls). Bioinformatics and functional analyses were conducted using clinical, cognitive, neuropathologic, whole-exome sequencing, and gene expression data obtained from a longitudinal cohort sample including 402 patients with AD and 647 controls. Data were analyzed between March 2017 and September 2018. Main Outcomes and Measures: Score, Firth, and sequence kernel association tests were used to test the association of AD risk with individual variants and genes in subgroups of APOE ε4 carriers and noncarriers. Results with P ≤ 1 × 10-5 were further evaluated in the replication data sets and combined by meta-analysis. Results: Among 3145 patients with AD and 4213 controls lacking ε4 (mean [SD] age, 83.4 [7.6] years; 4363 [59.3.%] women), novel genome-wide significant associations were obtained in the discovery sample with rs536940594 in AC099552 (odds ratio [OR], 88.0; 95% CI, 9.08-852.0; P = 2.22 × 10-7) and rs138412600 in GPAA1 (OR, 1.78; 95% CI, 1.44-2.2; meta-P = 7.81 × 10-8). GPAA1 was also associated with expression in the brain of GPAA1 (ß = -0.08; P = .03) and its repressive transcription factor, FOXG1 (ß = 0.13; P = .003), and global cognition function (ß = -0.53; P = .009). Significant gene-wide associations (threshold P ≤ 6.35 × 10-7) were observed for OR8G5 (P = 4.67 × 10-7), IGHV3-7 (P = 9.75 × 10-16), and SLC24A3 (P = 2.67 × 10-12) in 2377 patients with AD and 706 controls with ε4 (mean [SD] age, 75.2 [9.6] years; 1668 [54.1%] women). Conclusions and Relevance: The study identified multiple possible novel associations for AD with individual and aggregated rare variants in groups of individuals with and without APOE ε4 alleles that reinforce known and suggest additional pathways leading to AD.

20.
Am J Hum Genet ; 105(2): 258-266, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31230719

RESUMO

The transcriptome-wide association studies (TWASs) that test for association between the study trait and the imputed gene expression levels from cis-acting expression quantitative trait loci (cis-eQTL) genotypes have successfully enhanced the discovery of genetic risk loci for complex traits. By using the gene expression imputation models fitted from reference datasets that have both genetic and transcriptomic data, TWASs facilitate gene-based tests with GWAS data while accounting for the reference transcriptomic data. The existing TWAS tools like PrediXcan and FUSION use parametric imputation models that have limitations for modeling the complex genetic architecture of transcriptomic data. Therefore, to improve on this, we employ a nonparametric Bayesian method that was originally proposed for genetic prediction of complex traits, which assumes a data-driven nonparametric prior for cis-eQTL effect sizes. The nonparametric Bayesian method is flexible and general because it includes both of the parametric imputation models used by PrediXcan and FUSION as special cases. Our simulation studies showed that the nonparametric Bayesian model improved both imputation R2 for transcriptomic data and the TWAS power over PrediXcan when ≥1% cis-SNPs co-regulate gene expression and gene expression heritability ≤0.2. In real applications, the nonparametric Bayesian method fitted transcriptomic imputation models for 57.8% more genes over PrediXcan, thus improving the power of follow-up TWASs. We implement both parametric PrediXcan and nonparametric Bayesian methods in a convenient software tool "TIGAR" (Transcriptome-Integrated Genetic Association Resource), which imputes transcriptomic data and performs subsequent TWASs using individual-level or summary-level GWAS data.

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