Multiorgan MRI findings after hospitalisation with COVID-19 in the UK (C-MORE): a prospective, multicentre, observational cohort study

INTRODUCTION

The multiorgan impact of moderate to severe coronavirus infections in the post-acute phase is still poorly understood. We aimed to evaluate the excess burden of multiorgan abnormalities after hospitalisation with COVID-19, evaluate their determinants, and explore associations with patient-related outcome measures.

METHODS

In a prospective, UK-wide, multicentre MRI follow-up study (C-MORE), adults (aged ≥18 years) discharged from hospital following COVID-19 who were included in Tier 2 of the Post-hospitalisation COVID-19 study (PHOSP-COVID) and contemporary controls with no evidence of previous COVID-19 (SARS-CoV-2 nucleocapsid antibody negative) underwent multiorgan MRI (lungs, heart, brain, liver, and kidneys) with quantitative and qualitative assessment of images and clinical adjudication when relevant. Individuals with end-stage renal failure or contraindications to MRI were excluded. Participants also underwent detailed recording of symptoms, and physiological and biochemical tests. The primary outcome was the excess burden of multiorgan abnormalities (two or more organs) relative to controls, with further adjustments for potential confounders. The C-MORE study is ongoing and is registered with ClinicalTrials.gov, NCT04510025.

FINDINGS

Of 2710 participants in Tier 2 of PHOSP-COVID, 531 were recruited across 13 UK-wide C-MORE sites. After exclusions, 259 C-MORE patients (mean age 57 years [SD 12]; 158 [61%] male and 101 [39%] female) who were discharged from hospital with PCR-confirmed or clinically diagnosed COVID-19 between March 1, 2020, and Nov 1, 2021, and 52 non-COVID-19 controls from the community (mean age 49 years [SD 14]; 30 [58%] male and 22 [42%] female) were included in the analysis. Patients were assessed at a median of 5·0 months (IQR 4·2-6·3) after hospital discharge. Compared with non-COVID-19 controls, patients were older, living with more obesity, and had more comorbidities. Multiorgan abnormalities on MRI were more frequent in patients than in controls (157 [61%] of 259 vs 14 [27%] of 52; p<0·0001) and independently associated with COVID-19 status (odds ratio [OR] 2·9 [95% CI 1·5-5·8]; padjusted=0·0023) after adjusting for relevant confounders. Compared with controls, patients were more likely to have MRI evidence of lung abnormalities (p=0·0001; parenchymal abnormalities), brain abnormalities (p<0·0001; more white matter hyperintensities and regional brain volume reduction), and kidney abnormalities (p=0·014; lower medullary T1 and loss of corticomedullary differentiation), whereas cardiac and liver MRI abnormalities were similar between patients and controls. Patients with multiorgan abnormalities were older (difference in mean age 7 years [95% CI 4-10]; mean age of 59·8 years [SD 11·7] with multiorgan abnormalities vs mean age of 52·8 years [11·9] without multiorgan abnormalities; p<0·0001), more likely to have three or more comorbidities (OR 2·47 [1·32-4·82]; padjusted=0·0059), and more likely to have a more severe acute infection (acute CRP >5mg/L, OR 3·55 [1·23-11·88]; padjusted=0·025) than those without multiorgan abnormalities. Presence of lung MRI abnormalities was associated with a two-fold higher risk of chest tightness, and multiorgan MRI abnormalities were associated with severe and very severe persistent physical and mental health impairment (PHOSP-COVID symptom clusters) after hospitalisation.

INTERPRETATION

After hospitalisation for COVID-19, people are at risk of multiorgan abnormalities in the medium term. Our findings emphasise the need for proactive multidisciplinary care pathways, with the potential for imaging to guide surveillance frequency and therapeutic stratification.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Multiple ways to evade the bacteriostatic action of glyphosate in rhizobia include the mutation of the conserved serine 90 of the nitrogenase subunit NifH to alanine

The genome resequencing of spontaneous glyphosate-resistant mutants derived from the soybean inoculant E109 allowed identifying genes most likely associated with the uptake (gltL and cya) and metabolism (zigA and betA) of glyphosate, as well as with nitrogen fixation (nifH). Mutations in these genes reduce the lag phase and improve nodulation under glyphosate stress. In addition to providing glyphosate resistance, the amino acid exchange Ser90Ala in NifH increased the citrate synthase activity, growth rate and plant growth-promoting efficiency of E109 in the absence of glyphosate stress, suggesting roles for this site during both the free-living and symbiotic growth stages.

Exploring the Role of the NO-Detoxifying Enzyme HmpA in the Evolution of Domesticated Alfalfa Rhizobia

We have previously shown the extensive loss of genes during the domestication of alfalfa rhizobia and the high nitrous oxide emission associated with the extreme genomic instability of commercial inoculants. In the present note, we describe the molecular mechanism involved in the evolution of alfalfa rhizobia. Genomic analysis showed that most of the gene losses in inoculants are due to large genomic deletions rather than to small deletions or point mutations, a fact consistent with recurrent DNA double-strand breaks (DSBs) at numerous locations throughout the microbial genome. Genetic analysis showed that the loss of the NO-detoxifying enzyme HmpA in inoculants results in growth inhibition and high DSB levels under nitrosative stress, and large genomic deletions in planta but not in the soil. Therefore, besides its known function in the effective establishment of the symbiosis, HmpA can play a critical role in the preservation of the genomic integrity of alfalfa rhizobia under host-derived nitrosative stress.

Adaptation of a social vulnerability index for measuring social frailty among East African women

BACKGROUND

The number of older women living with HIV in Africa is growing, and their health outcomes may be adversely impacted by social frailty, which reflects deficits in social resources that accumulate over the lifespan. Our objective was to adapt a Social Vulnerability Index (SVI) originally developed in Canada for use in a study of older women living with or without HIV infection in Mombasa, Kenya.

METHODS

We adapted the SVI using a five-step process: formative qualitative work, translation into Kiswahili, a Delphi procedure, exploration of potential SVI items in qualitative work, and a rating and ranking exercise. Four focus group discussions (FGD) were conducted (three with women living with HIV and one with HIV-negative women), and two expert panels were constituted for this process.

RESULTS

Themes that emerged in the qualitative work were physical impairment with aging, decreased family support, a turn to religion and social groups, lack of a financial safety net, mixed support from healthcare providers, and stigma as an added burden for women living with HIV. Based on the formative FGD, the expert panel expanded the original 19-item SVI to include 34 items. The exploratory FGD and rating and ranking exercise led to a final 16-item Kenyan version of the SVI (SVI-Kenya) with six domains: physical safety, support from family, group participation, instrumental support, emotional support, and financial security.

CONCLUSIONS

The SVI-Kenya is a holistic index to measure social frailty among older women in Kenya, incorporating questions in multiple domains. Further research is needed to validate this adapted instrument.

Association of Performance on Dichotic Auditory Tests With Risk for Incident Dementia and Alzheimer Dementia

Importance

Age-related hearing difficulties can include problems with signal audibility and central auditory processing. Studies have demonstrated associations between audibility and dementia risk. To our knowledge, limited data exist to determine whether audibility, central processing, or both drive these associations.

Objective

To determine the associations between signal sensitivity, central auditory processing, and dementia and Alzheimer dementia (AD) risk.

Design, Setting, and Participants

This follow-up observational study of a sample from the prospective Adult Changes in Thought study of dementia risk was conducted at Kaiser Permanente Washington, a western Washington health care delivery system, and included 280 volunteer participants without dementia who were evaluated from October 2003 to February 2006 with follow-up through September 2018. Analyses began in 2019 and continued through 2021.

Exposures

Hearing tests included pure tone signal audibility, a monaural word recognition test, and 2 dichotic tests: the Dichotic Sentence Identification (DSI) test and the Dichotic Digits test (DDT).

Main Outcomes and Measures

Cognition was assessed biennially with the Cognitive Abilities Screening Instrument (range, 1-100; higher scores are better), and scores of less than 86 prompted clinical and neuropsychological evaluations. All data were reviewed at multidisciplinary consensus conferences, and standardized criteria were used to define incident cases of dementia and probable or possible AD. Cox proportional hazard models were used to determine associations with hearing test performance.

Results

A total of 280 participants (177 women [63%]; mean [SD] age, 79.5 [5.2] years). As of September 2018, there were 2196 person-years of follow-up (mean, 7.8 years) and 89 incident cases of dementia (66 not previously analyzed), of which 84 (94.4%) were AD (63 not previously analyzed). Compared with people with DSI scores of more than 80, the dementia adjusted hazard ratio (aHR) for DSI scores of less than 50 was 4.18 (95% CI, 2.37-7.38; P < .001); for a DSI score of 50 to 80, it was 1.82 (95% CI, 1.10-3.04; P = .02). Compared with people with DDT scores of more than 80, the dementia aHR for DDT scores of less than 50 was 2.66 (95% CI, 1.31-5.42; P = .01); for a DDT score of 50 to 80, it was 2.40 (95% CI, 1.45-3.98; P = .001). The AD results were similar. Pure tone averages were weakly and insignificantly associated with dementia and AD, and associations were null when controlling for DSI scores.

Conclusions and Relevance

In this cohort study, abnormal central auditory processing as measured by dichotic tests was independently associated with dementia and AD risk.

Development and evaluation of a target enrichment bait set for phylogenetic analysis of oomycetes

Target enrichment is a term that encompasses multiple related approaches where desired genomic regions are captured by molecular baits, leaving behind redundant or non-target regions in the genome, followed by amplification and next-generation sequencing of those captured regions. A molecular bait set was developed based on 426 single-copy, oomycete-specific orthologs and 3 barcoding genes. The bait set was tested on 27 oomycete samples (belonging to the Saprolegniales, Albuginales, and Peronosporales) derived from live and herbarium specimens, as well as control samples of true fungi and plants. Results show that (i) our method greatly enriches for the targeted orthologs on oomycete samples, but insignificantly on fungal and plant samples; (ii) an average of 263 out of 429 orthologs (61%) were recovered from oomycete live and herbarium specimens; (iii) sequencing roughly 100 000 read pairs per sample is sufficient for optimal ortholog recovery while maintaining low sequencing costs; and (iv) the expected relationships were recovered by phylogenetic analysis from the data generated. This is the first report of an oomycete-specific target enrichment method with broad potential applications for evolutionary and taxonomic studies. A key benefit of our target enrichment method is that it allows researchers to easily unlock the vast and unexplored oomycete genomic diversity stored in natural history collections.

Theoretical impact of the AT(N) framework on dementia using a community autopsy sample

The AT(N) research framework categorizes eight biomarker profiles using amyloid (A), tauopathy (T), and neurodegeneration (N), regardless of dementia status. We evaluated associations with dementia risk in a community-based cohort by approximating AT(N) profiles using autopsy-based neuropathology correlates, and considered cost implications for clinical trials for secondary prevention of dementia based on AT(N) profiles. We used Consortium to Establish a Registry for Alzheimer's Disease (moderate/frequent) to approximate A+, Braak stage (IV-VI) for T+, and temporal pole lateral ventricular dilation for (N)+. Outcomes included dementia prevalence at death and incidence in the last 5 years of life. A+T+(N)+ was the most common profile (31%). Dementia prevalence ranged from 14% (A-T-[N]-) to 79% (A+T+[N]+). Between 8% (A+T-[N]-) and 68% (A+T+[N]-) of decedents developed incident dementia in the last 5 years of life. Clinical trials would incur substantial expense to characterize AT(N). Many people with biomarker-defined preclinical Alzheimer's disease will never develop clinical dementia during life, highlighting resilience to clinical expression of AD neuropathologic changes and the need for improved tools for prediction beyond current AT(N) biomarkers.

Glucose-Dementia Association Is Consistent Over Blood Pressure/Antihypertensive Groups

BACKGROUND

Higher glucose levels are associated with dementia risk in people with and without diabetes. However, little is known about how this association might vary by hypertension status and antihypertensive treatment. Most studies on modifiable dementia risk factors consider each factor in isolation.

OBJECTIVE

To test the hypothesis that hypertension and antihypertensive treatments may modify associations between glucose levels and dementia.

METHODS

Analyses of data generated from a research study and clinical care of participants from a prospective cohort of dementia-free older adults, including glucose measures, diabetes and antihypertensive treatments, and blood pressure data. We defined groups based on blood pressure (hypertensive versus not, ≥140/90 mmHg versus <140/90 mmHg) and antihypertensive treatment intensity (0, 1, or ≥2 classes of antihypertensives). We used Bayesian joint models to jointly model longitudinal exposure and time to event data.

RESULTS

A total of 3,056 participants without diabetes treatment and 480 with diabetes treatment were included (mean age at baseline, 75.1 years; mean 7.5 years of follow-up). Higher glucose levels were associated with greater dementia risk among people without and with treated diabetes. Hazard ratios for dementia were similar across all blood pressure/antihypertensive treatment groups (omnibus p = 0.82 for people without and p = 0.59 for people with treated diabetes).

CONCLUSION

Hypertension and antihypertensive treatments do not appear to affect the association between glucose and dementia risk in this population-based longitudinal cohort study of community-dwelling older adults. Future studies are needed to examine this question in midlife and by specific antihypertensive treatments.

Spontaneous Mutations in the Nitrate Reductase Gene napC Drive the Emergence of Eco-friendly Low-N2O-Emitting Alfalfa Rhizobia in Regions with Different Climates

We have recently shown that commercial alfalfa inoculants (e.g., Sinorhizobium meliloti B399), which are closely related to the denitrifier model strain Sinorhizobium meliloti 1021, have conserved nitrate, nitrite, and nitric oxide reductases associated with the production of the greenhouse gas nitrous oxide (N₂O) from nitrate but lost the N₂O reductase related to the degradation of N₂O to gas nitrogen. Here, we screened a library of nitrogen-fixing alfalfa symbionts originating from different ecoregions and containing N₂O reductase genes and identified novel rhizobia (Sinorhizobium meliloti INTA1-6) exhibiting exceptionally low N₂O emissions. To understand the genetic basis of this novel eco-friendly phenotype, we sequenced and analyzed the genomes of these strains, focusing on their denitrification genes, and found mutations only in the nitrate reductase structural gene napC. The evolutionary analysis supported that, in these natural strains, the denitrification genes were inherited by vertical transfer and that their defective nitrate reductase napC alleles emerged by independent spontaneous mutations. In silico analyses showed that mutations in this gene occurred in ssDNA loop structures with high negative free energy (-ΔG) and that the resulting mutated stem-loop structures exhibited increased stability, suggesting the occurrence of transcription-associated mutation events. In vivo assays supported that at least one of these ssDNA sites is a mutational hot spot under denitrification conditions. Similar benefits from nitrogen fixation were observed when plants were inoculated with the commercial inoculant B399 and strains INTA4-6, suggesting that the low-N₂O-emitting rhizobia can be an ecological alternative to the current inoculants without resigning economic profitability.

Serum Cholesterol and Incident Alzheimer's Disease: Findings from the Adult Changes in Thought Study

OBJECTIVES

To evaluate associations between high-density lipoprotein cholesterol (HDL) and non-HDL-C levels at specific ages and subsequent Alzheimer's disease (AD) risk.

DESIGN

Prospective population-based cohort study.

SETTING

Adult Changes in Thought (ACT) Study.

PARTICIPANTS

Individuals aged 65 and older with no dementia at ACT Study entry. We identified separate, partially overlapping subcohorts of ACT participants who were eligible for each age band-specific analysis (50-59, n = 1,088; 60-69, n = 2,852; 70-79, n = 2,344; 80-89, n = 537).

MEASUREMENTS

Exposure consisted of clinical measures of total cholesterol (TC) and HDL-C from laboratory data during a given age band. Outcomes of incident AD were assessed post-age band using standard research diagnostic criteria. Statistical analyses used adjusted Cox proportional hazards regression models for each exposure and outcome pair within an age band. Cholesterol exposures were modeled using cubic splines.

RESULTS

For non-HDL-C, we found a statistically significant association with AD risk in the 60 to 69 (omnibus p = .005) and 70 to 79 (omnibus p = .04) age bands, suggesting a potential U-shaped relationship (greater risk at low and high levels). For example, in people aged 60 to 69, those with an average non-HDL-C level of 120 mg/DL had a 29% greater AD hazard (hazard ratio (HR)=1.29, 95% confidence interval (CI)=1.04-1.61) than those with an average non-HDL-C level of 160 mg/dL, whereas those with an average non-HDL-C level of 210 mg/dL had a 16% greater hazard (HR=1.16, 95% CI=1.01-1.33). We did not find a statistically significant association between HDL-C and AD risk.

CONCLUSION

People with low (120 mg/dL) and high (210 mg/dL) non-HDL-C levels during their 60s and 70s had modestly higher risk of AD than those with intermediate (160 mg/dL) levels. The extreme age bands (50s and 80s) had small sample sizes. J Am Geriatr Soc 66:2344-2352, 2018.

Cognitive Trajectory Changes Over 20 Years Before Dementia Diagnosis: A Large Cohort Study

BACKGROUND/OBJECTIVES

Longitudinal studies have shown an increase in cognitive decline many years before clinical diagnosis of dementia. We sought to estimate changes, relative to "normal" aging, in the trajectory of scores on a global cognitive function test-the Cognitive Abilities Screening Instrument (CASI).

DESIGN

A prospective cohort study.

SETTING

Community-dwelling members of a U.S. health maintenance organization.

PARTICIPANTS

Individuals aged 65 and older who had no dementia diagnosis at baseline and had at least two visits with valid CASI test score (N = 4,315).

MEASUREMENTS

Average longitudinal trajectories, including changes in trajectory before clinical diagnosis in those who would be diagnosed with dementia, were estimated for CASI item response theory (IRT) scores. The impact of sex, education level, and APOE genotype on cognitive trajectories was assessed.

RESULTS

Increased cognitive decline relative to "normal" aging was evident in CASI IRT at least 10 years before clinical diagnosis. Male gender, lower education, and presence of ≥1 APOE ε4 alleles were associated with lower average IRT scores. In those who would be diagnosed with dementia, a trajectory change point was estimated at an average of 3.1 years (95% confidence interval 3.0-3.2) before clinical diagnosis, after which cognitive decline appeared to accelerate. The change point did not differ by sex, education level, or APOE ε4 genotype. There were subtle differences in trajectory slopes by sex and APOE ε4 genotype, but not by education.

CONCLUSION

Decline in average global cognitive function was evident at least 10 years before clinical diagnosis of dementia. The decline accelerated about 3 years before clinical diagnosis.

Incidence of cognitively defined late-onset Alzheimer's dementia subgroups from a prospective cohort study

INTRODUCTION

There may be biologically relevant heterogeneity within typical late-onset Alzheimer's dementia.

METHODS

We analyzed cognitive data from people with incident late-onset Alzheimer's dementia from a prospective cohort study. We determined individual averages across memory, visuospatial functioning, language, and executive functioning. We identified domains with substantial impairments relative to that average. We compared demographic, neuropathology, and genetic findings across groups defined by relative impairments.

RESULTS

During 32,286 person-years of follow-up, 869 people developed Alzheimer's dementia. There were 393 (48%) with no domain with substantial relative impairments. Some participants had isolated relative impairments in memory (148, 18%), visuospatial functioning (117, 14%), language (71, 9%), and executive functioning (66, 8%). The group with isolated relative memory impairments had higher proportions with ≥ APOE ε4 allele, more extensive Alzheimer's-related neuropathology, and higher proportions with other Alzheimer's dementia genetic risk variants.

DISCUSSION

A cognitive subgrouping strategy may identify biologically distinct subsets of people with Alzheimer's dementia.

An Investigation of Impedance Control for Robot Manipulators

This article documents investigations into impedance control carried out on a direct drive robot manipulator. Both linear and nonlinear versions of impedance contrallers have been investigated. The two impedance controllers have been simu lated numerically and implemented on Carleton University's direct drive robot. The performance of these controllers is ex perimentally compared in terms of force trajectory following and contact stability. The article highlights the practical and experimental limitations of the proposed methods. Furthermore, the experimental results indicate that the controller design, the manipulator kinematics, and the desired task must all be considered and evaluated simultaneously.

Importance of home study visit capacity in dementia studies

INTRODUCTION

The importance of home research study visit capacity in Alzheimer's disease (AD) studies is unknown.

METHODS

All evaluations are from the prospective Adult Changes in Thought study. Based on analyses of factors associated with volunteering for a new in-clinic initiative, we analyzed AD risk factors and the relevance of neuropathologic findings for dementia comparing all data including home visits, and in-clinic data only. We performed bootstrapping to determine whether differences were greater than expected by chance.

RESULTS

Of the 1781 people enrolled during 1994-1996 with ≥1 follow-up, 1369 (77%) had in-clinic data, covering 61% of follow-up time. In-clinic data resulted in excluding 76% of incident dementia and AD cases. AD risk factors and the relevance of neuropathologic findings for dementia were both different with in-clinic data.

DISCUSSION

Limiting data collection in AD studies to research clinics alone likely reduces power and also can lead to erroneous inferences.

Evaluation of two novel barcodes for species recognition of opportunistic pathogens in Fusarium

The genus Fusarium includes more than 200 species of which 73 have been isolated from human infections. Fusarium species are opportunistic human pathogens with variable aetiology. Species determination is best made with the combined phylogeny of protein-coding genes such as elongation factor (TEF1), RNA polymerase (RPB2) and the partial β-tubulin (BT2) gene. The internal transcribed spacers 1, 2 and 5.8S rRNA gene (ITS) have also been used, however, ITS cannot discriminate several closely related species and has nonorthologous copies in Fusarium. Currently, morphological approaches and tree-building methods are in use to define species and to discover hitherto undescribed species. Aftter a species is defined, DNA barcoding approaches can be used to identify species by the presence or absence of discrete nucleotide characters. We demonstrate the potential of two recently discovered DNA barcode loci, topoisomerase I (TOP1) and phosphoglycerate kinase (PGK), in combination with other routinely used markers such as TEF1, in an analysis of 144 Fusarium strains belonging to 52 species. Our barcoding study using TOP1 and PKG provided concordance of molecular data with TEF1. The currently accepted Fusarium species sampled were well supported in phylogenetic trees of both new markers.

Glucose levels and risk of dementia

BACKGROUND

Diabetes is a risk factor for dementia. It is unknown whether higher glucose levels increase the risk of dementia in people without diabetes.

METHODS

We used 35,264 clinical measurements of glucose levels and 10,208 measurements of glycated hemoglobin levels from 2067 participants without dementia to examine the relationship between glucose levels and the risk of dementia. Participants were from the Adult Changes in Thought study and included 839 men and 1228 women whose mean age at baseline was 76 years; 232 participants had diabetes, and 1835 did not. We fit Cox regression models, stratified according to diabetes status and adjusted for age, sex, study cohort, educational level, level of exercise, blood pressure, and status with respect to coronary and cerebrovascular diseases, atrial fibrillation, smoking, and treatment for hypertension.

RESULTS

During a median follow-up of 6.8 years, dementia developed in 524 participants (74 with diabetes and 450 without). Among participants without diabetes, higher average glucose levels within the preceding 5 years were related to an increased risk of dementia (P=0.01); with a glucose level of 115 mg per deciliter (6.4 mmol per liter) as compared with 100 mg per deciliter (5.5 mmol per liter), the adjusted hazard ratio for dementia was 1.18 (95% confidence interval [CI], 1.04 to 1.33). Among participants with diabetes, higher average glucose levels were also related to an increased risk of dementia (P=0.002); with a glucose level of 190 mg per deciliter (10.5 mmol per liter) as compared with 160 mg per deciliter (8.9 mmol per liter), the adjusted hazard ratio was 1.40 (95% CI, 1.12 to 1.76).

CONCLUSIONS

Our results suggest that higher glucose levels may be a risk factor for dementia, even among persons without diabetes. (Funded by the National Institutes of Health.)

Enhancing the power of genetic association studies through the use of silver standard cases derived from electronic medical records

The feasibility of using imperfectly phenotyped "silver standard" samples identified from electronic medical record diagnoses is considered in genetic association studies when these samples might be combined with an existing set of samples phenotyped with a gold standard technique. An analytic expression is derived for the power of a chi-square test of independence using either research-quality case/control samples alone, or augmented with silver standard data. The subset of the parameter space where inclusion of silver standard samples increases statistical power is identified. A case study of dementia subjects identified from electronic medical records from the Electronic Medical Records and Genomics (eMERGE) network, combined with subjects from two studies specifically targeting dementia, verifies these results.

Frailty and incident dementia

BACKGROUND

We sought to examine whether frailty is associated with dementia, Alzheimer's disease (AD), and non-AD dementia risk.

METHODS

This is a prospective population-based cohort derived from an integrated health maintenance organization. The sample consisted of 2,619 participants aged 65 and older without dementia at baseline followed from 1994 to 2010. Frailty was defined as having at least 3 of the following criteria: weakness (grip strength), slowness (walking speed), weight loss, low physical activity, and self-reported exhaustion. Follow-up occurred every 2 years to identify incident dementia, possible or probable AD, and non-AD dementia using standard research criteria. Covariates came from self-report and study measures. We used adjusted Cox proportional hazards models to examine the association between frailty and each outcome.

RESULTS

Over a mean follow-up of 6.5 years, 521 participants developed dementia (of which 448 developed AD). In the model adjusted for age, sex, education, and race, the hazard ratio for frailty was 1.78 (95% confidence interval [CI] 1.32-2.40). In the fully adjusted models, the hazard ratio for frailty was 1.20 for all-cause dementia (95% CI 0.85-1.69), 1.08 for AD (95% CI 0.74-1.57), and 2.57 for non-AD dementia (95% CI 1.08-6.11). For all-cause dementia, we found an interaction between baseline cognitive score and frailty (p = .02); hazard ratio for frailty was 1.78 for those with higher global cognition (95% CI 1.14-2.78) and 0.79 for those with lower global cognition (95% CI 0.50-1.26).

CONCLUSION

Frailty was associated with dementia when adjusting only for demographic variables but not in the fully adjusted model. Frailty was associated with higher risk of developing non-AD dementia but not AD. Although frailty was not associated with all-cause dementia in the entire sample, an association did exist in participants with higher cognitive scores. Mechanisms underlying these associations remain to be elucidated.

Temporal relationship between depression and dementia: findings from a large community-based 15-year follow-up study

CONTEXT

Late-life depression is associated with increased risk of dementia, but the temporal relationship between depression and development of dementia remains unclear.

OBJECTIVES

To examine the association between risk of dementia and baseline depressive symptoms; history of depression, particularly early-life (<50 years) vs late-life depression (≥50 years); and individual domains of the Center for Epidemiologic Studies Depression Scale.

DESIGN

A large cohort with initially nondemented participants was followed up biennially for up to 15 years. Baseline depressive symptoms were assessed using the 11-item version of the Center for Epidemiologic Studies Depression Scale; presence of significant depressive symptoms was defined as a score of 11 or greater. Self-reported history of depression was collected at the baseline interview. Cox proportional hazards regression was used to assess the association between depression and dementia risk.

SETTING

Population-based cohort drawn from members of the Group Health Cooperative in Seattle, Washington.

PARTICIPANTS

A cohort of 3410 participants without dementia aged at least 65 years.

RESULTS

During a mean of 7.1 years of follow-up, 658 participants (19.3%) developed dementia. At baseline, 9.4% of participants had presence of significant depressive symptoms, and 21.2% reported a history of depression. The adjusted hazard ratio for dementia associated with baseline depressive symptoms was 1.71 (95% confidence interval, 1.37-2.13), after adjusting for age at entry, sex, educational level, and wave of enrollment. Compared with participants without depression history, those with late-life depression were at increased dementia risk (adjusted hazard ratio, 1.46; 95% confidence interval, 1.16-1.84), but early-life depression had no association with dementia risk (1.10 [0.83-1.47]). Depressed mood (adjusted hazard ratio, 1.48; 95% confidence interval, 1.25-1.76) and perceived performance difficulty (1.39 [1.15-1.67]) were independently associated with dementia.

CONCLUSION

This study confirmed that late-life depression is associated with increased risk of dementia and supplied evidence that late-life depression may be an early manifestation of dementia rather than increasing risk for dementia.

Atrial fibrillation and risk of dementia: a prospective cohort study

OBJECTIVES

To determine whether atrial fibrillation (AF) is associated with risk of incident dementia or Alzheimer's disease (AD), beyond its effect on stroke.

DESIGN

Prospective cohort study.

SETTING

An integrated healthcare delivery system.

PARTICIPANTS

A population-based sample of 3,045 community-dwelling adults aged 65 and older without dementia or clinical stroke followed from 1994 to 2008.

MEASUREMENTS

AF was identified from health plan electronic data using International Classification of Diseases, Ninth Revision, codes from inpatient and outpatient encounters. Covariates came from self-report, study measures, and health plan data. Participants were screened every 2 years using the Cognitive Abilities Screening Instrument (range 0-100), with detailed neuropsychological and clinical assessment of those scoring less than 86. A multidisciplinary consensus committee determined diagnoses of all-cause dementia and possible or probable AD using standard research criteria.

RESULTS

AF was present in 132 (4.3%) participants at baseline and was diagnosed in 370 (12.2%) more over a mean of 6.8 years of follow-up; 572 participants (18.8%) developed dementia (449 with AD). The adjusted hazard ratio associated with AF was 1.38 (95% confidence interval (CI)=1.10-1.73) for all-cause dementia and 1.50 (95% CI=1.16-1.94) for possible or probable AD. Results were similar for participants with and without clinically recognized stroke during follow-up and in sensitivity analyses examining only probable AD.

CONCLUSION

AF is associated with higher risk of developing AD and dementia. Future studies should examine whether specific treatments, including optimal anticoagulation, can decrease this risk.

Histamine-2 receptor antagonist use and incident dementia in an older cohort

OBJECTIVES

To examine whether histamine-2 receptor antagonist medications (H2RAs) are associated with a lower incidence of all-cause dementia or Alzheimer's disease (AD), as some studies have suggested.

DESIGN

Prospective population-based cohort

SETTING

Group Health, an integrated health maintenance organization, Seattle, Washington.

PARTICIPANTS

Two thousand nine hundred twenty-three participants aged 65 and older without dementia at baseline, with initial recruitment between 1994 and 1996.

MEASUREMENTS

Follow-up occurred every 2 years to identify incident dementia and AD using standard criteria. Exposure to H2RAs was determined based on automated pharmacy data. Three aspects of exposure (time-varying) were examined based on standard daily dose (SDD): cumulative use, intensity of use (highest SDD in any prior 2-year window), and cumulative use stratified according to recency (1-3 years vs >3 years before).

RESULTS

Over a mean follow-up of 6.7 years, 585 subjects developed dementia (453 developed AD). Total cumulative exposure was not associated with dementia (P=.35; omnibus test) or AD (P=.23). The adjusted hazard ratios for the highest exposure category (>1,080 SDDs) compared with light or no use were 1.28 (95% confidence interval (CI)=0.95-1.72) for dementia and 1.41 (95% CI=1.00-1.97) for AD. Intensity of use was not associated with dementia (P=.39) or AD (P=.63). Examining exposure according to recent and distant cumulative use also showed no association with dementia (P=.11) or AD (P=.30).

CONCLUSION

No association was found between H2RA use and risk of all-cause dementia or AD using more-detailed and -extensive information about past H2RA use than any prior study.

Age-varying association between statin use and incident Alzheimer's disease

OBJECTIVES

To determine whether risk reduction of statins for Alzheimer's disease (AD) varies by age or presence of apolipoprotein E (APOE) epsilon4 allele.

DESIGN

A cohort of cognitively intact elderly participants was assessed biennially for dementia and AD.

SETTING

Community based.

PARTICIPANTS

Three thousand three hundred ninety-two members of a health maintenance organization (HMO) aged 65 and older and without dementia.

MEASUREMENTS

Statin use was identified from the HMO pharmacy database, and proportional hazards models were applied with statin use as a time-dependent covariate to assess the association between statins and AD and the modifying effects of age and the APOE epsilon4 allele.

RESULTS

Over an average of 6.1 years of follow-up of 3,099 participants, 263 participants developed probable AD. The adjusted hazard ratio (aHR) for statin use was 0.62 (95% confidence interval (CI)=0.40-0.97) for AD in models including demographic characteristics and vascular risk factors as covariates. The strength of the association between statins and AD diminished with age (statin-by-age at entry interaction P=.04); the aHR in those younger than 80 was 0.44 (95% CI=0.25-0.78), versus 1.22 (95% CI=0.61-2.42) for aged 80 and older. The interaction term for statin use-by-APOE epsilon4 was not significant (P=.65).

CONCLUSION

This enlarged study confirms earlier findings that statin therapy in early old age, but not in late age, may be associated with a lower risk of AD. The relationship between statin use and AD was consistent across APOE genotypes.

Cognitive impairment in older adults without dementia: clinical and pathologic outcomes in a community-based sample

This study examines clinical and neuropathologic characteristics of 37 participants in a community-based dementia series who had cognitive complaints at enrollment but did not meet dementia criteria. Participants had neuropsychological testing, were followed until death, and underwent autopsy. Twenty-four participants progressed to dementia, and their baseline characteristics were analyzed. Of the 24, 13 met criteria for neuropathologic Alzheimer disease (AD). The 13 participants who progressed to neuropathologic AD (mean intake age 78.5 +/- 7.7, mean enrollment 6.4 +/- 2.1 years) performed worse than the 11 who progressed to neuropathologic non-AD dementias (mean intake age 79.0 +/- 6.0, mean enrollment 6.0 +/- 3.2 years) on baseline Wechsler Memory Scale (WMS) delayed logical memory (3.4 +/- 2.9 vs 6.3 +/- 3.9, P = .05) and delayed visual reproduction (1.4 +/- 2.1 vs 3.1 +/- 2.7, P = .02). These observations are consistent with the view that nondemented patients with underlying AD may be more likely to present with memory than nonmemory cognitive impairment.

Blood pressure and brain injury in older adults: findings from a community-based autopsy study

OBJECTIVES

To examine correlations between blood pressure (BP) and dementia-related pathological brain changes in a community-based autopsy sample.

DESIGN

Prospective cohort study.

SETTING

A large health maintenance organization in Seattle, Washington.

PARTICIPANTS

A cohort of 250 participants aged 65 and older and cognitively normal at time of enrollment in the Adult Changes in Thought (ACT) Study and who underwent autopsy.

MEASUREMENTS

BP and history of antihypertensive treatment were taken at enrollment. A linear regression model was used to examine the relationship between BP (systolic (SBP) and diastolic (DBP)) at enrollment and pathological changes in the cerebrum (cystic macroscopic infarcts, microinfarcts, neuritic plaques, neurofibrillary tangles, and cortical Lewy bodies).

RESULTS

The presence of more than 2 microinfarcts, but not any other pathological change, was independently associated with SBP in younger participants (65-80, n=137) but not in older participants (>80, n=91). The relative risk (RR) for more than two microinfarcts with each 10-mmHg increase in SBP was 1.15 (95% confidence interval (CI)=1.00-1.33) in the younger participants, adjusted for age at entry, sex, and time to death. This RR was particularly strong in younger participants not taking antihypertensive medications (RR=1.48, 95% CI=1.21, 1.81); significant associations were not observed in participants treated for hypertension. Findings for DBP were negative.

CONCLUSION

The association between high SBP and cerebrovascular damage in untreated older adults (65-80) suggests that adequate hypertension treatment may reduce dementia risk by minimizing microvascular injury to cerebrum.

Age-Varying Association Between Blood Pressure and Risk of Dementia in Those Aged 65 and Older: A Community-Based Prospective Cohort Study

OBJECTIVES

To assess variation in the association between blood pressure (BP) and risk for dementia across a spectrum of older ages and to examine BP changes before dementia onset.

DESIGN

Prospective cohort study.

SETTING

A large health maintenance organization in Seattle, Washington.

PARTICIPANTS

A cohort of 2,356 members of a large health maintenance organization aged 65 and older who were initially without dementia.

MEASUREMENTS

Dementia diagnosis was assessed biennially, and systolic (SBP) and diastolic BP (DBP) were measured at baseline and at four follow-up assessments. Cox proportional hazards models were used to estimate hazard ratios (HRs) for dementia and Alzheimer's disease (AD) associated with baseline BP in different age groups.

RESULTS

Within the youngest age group (65-74 at enrollment) a greater risk for dementia was found in participants with high SBP (> or = 160 mmHg) (hazard ratio (HR) = 1.60, 95% confidence interval (CI) = 1.01-2.55) or borderline-high DBP (80-89 mmHg) (HR = 1.59, 95% CI = 1.07-2.35) than for those with normal BP (SBP < 140 mmHg and DBP < 80 mmHg). The dementia risk associated with SBP declined with increasing age (SBP-by-age interaction, P=.01). SBP declined similarly with aging in subjects who developed dementia and those who did not. Thus, in this sample, the association between SBP and dementia risk was not dependent on when BP was measured in relation to onset of dementia.

CONCLUSION

High SBP was associated with greater risk of dementia in the young elderly (< 75) but not in older subjects. Adequate control of hypertension in early old age may reduce the risk for dementia.

Predicting lewy body pathology in a community-based sample with clinical diagnosis of Alzheimer's disease

Accurate antemortem prediction of Lewy body pathology in patients with dementia is problematic. This study generates a model that better predicts Lewy body pathology in community-based patients with clinical Alzheimer's disease. Lewy body pathology was detected in 80 of 152 participants (52.6%) with an initial diagnosis of probable Alzheimer's disease. In a stepwise logistic regression model, female gender, lower education, being married, bradykinesia, hallucinations, and absence of irritability predicted the greatest likelihood of Lewy body pathology. The predictive model correctly diagnosed Lewy body pathology with an estimated sensitivity of 75%, specificity of 68%, and accuracy of 72%; the area under the receiver operating characteristic curve was 0.75. In a community-based autopsy sample, this predictive model confirmed parkinsonism and hallucinations as important predictors of Lewy body pathology in patients with clinical Alzheimer's disease. The model also identified other demographic and clinical characteristics that might enhance the prediction of Lewy body pathology.

Conservation of Pitx1 expression during amphibian limb morphogenesis

In contrast to the pattern of limb emergence in mammals, chicks, and the newt N. viridescens, embryos such as Xenopus laevis and Eleutherodactylus coqui initiate pelvic limb buds before they develop pectoral ones. We studied the expression of Pitx1 in X. laevis and E. coqui to determine if this paired-like homeodomain transcription factor directs differentiation specifically of the hindlimb, or if it directs the second pair of limbs to form, namely the forelimbs. We also undertook to determine if embryonic expression patterns were recapitulated during the regeneration of an amputated limb bud. Pitx1 is expressed in hindlimbs in both X. laevis and E. coqui, and expression is similar in both developing and regenerating limb buds. Expression in hindlimbs is restricted to regions of proliferating mesenchyme.