Cohort Of Older Adults Research Articles

Longitudinal Changes in a Claims-Based Frailty Proxy Measure Compared to Concurrent Changes in the Fried Frailty Phenotype.

Frailty is a dynamic aging-related syndrome, but measuring frailty transitions is challenging. The Faurot frailty index is a validated Medicare claims-based frailty proxy based on demographic and billing information. We evaluated whether 3-year changes in the Faurot frailty index were consistent with concurrent changes in the frailty phenotype in a cohort of older adults. We used longitudinal data from the National Health and Aging Trends Study (NHATS) with Medicare claims linkage (2010-2018). We identified older adults (66+ years) in the 2011 and 2015 NHATS cohorts with at least 1 year of Medicare fee-for-service continuous enrollment (N = 6 951). We described annual changes in mean claims-based frailty for up to 3 years, based on concurrent transitions in the frailty phenotype. At baseline, 32% were robust, 48% prefrail, and 19% frail based on the frailty phenotype. Mean claims-based frailty for older adults who were robust at baseline and worsened to frail increased over 3 years (0.09-0.25). Similarly, those who worsened from prefrail to frail experienced an increase in mean claims-based frailty (0.14-0.26). Improvements in the frailty phenotype did not correspond to decreases in claims-based frailty. Older adults whose frailty phenotype improved over time had a lower baseline claims-based frailty score than those who experienced stable or worsening frailty. Older adults who experienced a frailty phenotype worsening over 3 years experienced concurrent increases in the Faurot frailty index. Our results suggest that claims data may be used to identify clinically meaningful worsening in frailty.

Exploratory Mass Spectrometry of Cerebrospinal Fluid from Persons with Autopsy-Confirmed LATE-NC.

Common neuropathologies associated with dementia include Alzheimer's disease neuropathologic change (ADNC) and limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC). Biofluid proteomics provides a window into the pathobiology of dementia and the information from biofluid tests may help guide clinical management. Participants (n = 29) had been autopsied and had antemortem CSF draws in a longitudinal cohort of older adults at the University of Kentucky AD Research Center. Cases were designated as LATE-NC + if they had LATE-NC stage > 1 (n = 9); the remaining 20 cases were designated LATE-NC-. This convenience sample of CSF specimens was analyzed in two separate processes: From one group, aliquots were depleted of highly abundant proteins using affinity spin columns. Tryptic digests of sample proteins were subjected to liquid chromatographic separation and mass spectrometry. Relative quantification was performed using Sciex software. Peptides referent to a total of 949 proteins were identified in the samples depleted of abundant proteins, and 820 different proteins were identified in the non-depleted samples. When the Bonferroni/false-discovery statistical correction was applied to account for having made multiple comparison tests, only 4 proteins showed differential expression (LATE-NC + vs LATE-NC-) in the non-depleted samples (RBP4, MIF, IGHG3, and ITM2B). Post hoc western blots confirmed that RBP4 expression was higher in the LATE-NC + cases at the group level. In summary, an exploratory assessment of proteomes of autopsy-confirmed LATE-NC and non-LATE-NC CSF did not demonstrate a clear-cut proteomic fingerprint that distinguished the two groups. There was, however, an increase in RBP4 protein levels in CSF from LATE-NC cases.

Multimorbidity, health Literacy, and quality of life among older adults in an urban slum in India: a community-based cross-sectional study

BackgroundIndia is experiencing a rising burden of chronic disease multimorbidity due to an aging population and epidemiological transition. Older adults residing in urban slums are especially vulnerable due to challenges in managing multimorbidity amid deprived living conditions. This study aimed to assess the prevalence of multimorbidity, associated health literacy, and quality of life impact in this population.MethodsA community-based cross-sectional study was conducted among 800 adults aged ≥ 65 years in an urban slum in Gujarat, India. Data on sociodemographics, physical and mental health conditions, health literacy (HLS-SF-47), quality of life (Short Form-12 scale), and social determinants of health were collected. Multimorbidity is ≥ 2 physical or mental health conditions in one person.ResultsThe prevalence of multimorbidity was 62.5% (500/800). Multimorbidity was significantly associated with lower physical component summary (PCS) and mental component summary (MCS) scores on the SF-12 (p < 0.001). After adjusting for sociodemographic variables, the odds ratio of 0.81 indicates that for every 1 unit increase in the health literacy score, the odds of having multimorbidity decrease by 19%. Older age within the older adult cohort (per year increase) was associated with greater odds of multimorbidity (AOR 1.05, 95% CI 1.02–1.09). Physical inactivity (AOR 1.68, 95% CI 1.027–2.77) and lack of social support (AOR 1.57, 95% CI 1.01–2.45) also increased the likelihood of multimorbidity.ConclusionThere is a substantial burden of multimorbidity among urban slum dwellers aged ≥ 65 years in India, strongly linked to modifiable risk factors like poor health literacy and social determinants of health. Targeted interventions are essential to alleviate this disproportionate burden among urban slum older adults.

Facilitating co-design among older adults in a digital setting: methodological challenges and opportunities

ABSTRACT Healthy ageing is a global priority due to a growing older population, which increases the need for preventive measures and tailored technology. In health technology development, co-design is emphasised as a valuable strategy to support a person-centred approach. Co-design, a value-driven and collaborative approach, involves end users in development processes to overcome barriers connected to capability, opportunity, and motivation. While a growing number of older adults are involved in design processes, there is a deficit of suitable methodologies for achieving active involvement. Additionally, the COVID-19 pandemic necessitated a shift to developing methodological skills and tools to facilitate co-design remotely in a digital setting. Here, we draw on experiences of conducting iterative co-design workshops with a Canadian and a Swedish cohort of older adults about technology development to support mobility, balance, and confidence in daily movement. We describe and discuss methodological and ethical challenges and opportunities to provide recommendations for conducting co-design research in a digital setting with older adults (+65 years). Our recommendations include the use of live mind mapping to facilitate participation involvement, and we address the issue of ‘homework’ in co-design and the importance of setting expectations.

Cardiac Mechanics and the Risk of Atrial Fibrillation in a Community-Based Cohort of Older Adults.

Assessment of cardiac structure and function improves risk prediction of new-onset atrial fibrillation (AF) in different populations. We aimed to comprehensively compare standard and newer measures of cardiac structure and function in improving prediction of AF in a cohort of older adults without history of AF and stroke. We included 5050 participants without prevalent AF and stroke (mean age 75 ± 5 years, 59% women and 22% Black) from the Atherosclerosis Risk in Communities (ARIC) study who underwent complete 2-dimensional echocardiography, including speckle-tracking analysis of the left ventricle (LV) and left atrium (LA). We assessed the association of cardiac measures with incident AF (including atrial flutter) and quantified the extent to which these measures improved model discrimination and risk classification of AF compared with the CHARGE-AF score. Over a median follow-up time of 7 years, 676 participants developed AF (incidence rate, 2.13 per 100 person-years). LV mass index and wall thickness, E/e' and measures of LA structure and function, but not LV systolic function, were associated with incident AF, after accounting for confounders. Above all, LA reservoir strain, contraction strain, and LA minimal volume index (C-statistics [95%Confidence interval]: 0.73 [0.70,0.75], 0.72 [0.70,0.75] and 0.72 [0.69,0.75], respectively) significantly improved the risk discrimination of the CHARGE-AF score (baseline C-statistic: 0.68 [0.65,0.70]) and achieved the highest category-based net reclassification improvement (29%, 24% and 20%, respectively). In a large cohort of older adults without prevalent AF and stroke, measures of LA function improved the prediction of AF more than other conventional cardiac measures.

Visceral Adiposity Index as a Predictor for Metabolic Syndrome in a Cohort of Older Adults With Obesity

Visceral Adiposity Index as a Predictor for Metabolic Syndrome in a Cohort of Older Adults With Obesity

Association of Caregiving Receipt With Mental Health Utilization in a National Cohort of Older Adults

ObjectiveThere exist significant age disparities in mental health (MH) utilization, such that older adults, including older veterans, are much less likely to use MH services. In-home caregivers represent a novel, yet understudied, pathway to increase appropriate utilization. We sought to examine the association between receiving caregiving assistance and MH utilization and test moderation effects of cognitive status and depression severity in a sample of older veterans. MethodsCross-sectional, mixed effects logistic regression with moderation analyses was used with a unique data resource combining survey data from the 2000–2012 U.S. Health and Retirement Study with Veterans Affairs (VA) healthcare administrative records. The analytic sample included N=1,957 Community-dwelling veterans (mean age 68.2 [9.7]), primarily male (96.5%) and non-Hispanic white (77.0%). Measures included MH utilization extracted from VA records or self-report; CESD-8 for depressive symptoms; and the Langa-Weir cognitive status classification using the modified TICS. ResultsAfter accounting for demographics, spousal caregiver availability, health factors, and socioeconomic status, caregiving receipt was associated with two-fold odds of MH utilization, compared to receiving no assistance (8,839 person-year observations; OR = 2.02; 95% CI 1.54–2.65) and remained similar following VA policy changes to enhance MH access. Exploratory analyses revealed that categories of cognition and depressive symptoms may moderate the association. ConclusionReceipt of any in-home caregiving is associated with increased likelihood of MH use by older adults. Caregivers may represent an underutilized resource to reduce age-related mental health access disparities.

Association Between Plasma Levels of Vitamin B12 and Cognitive Trajectory: A Community-Based Cohort of Older Adults in China

Association Between Plasma Levels of Vitamin B12 and Cognitive Trajectory: A Community-Based Cohort of Older Adults in China

Frailty and falls in community-dwelling older adults in sub-Saharan Africa: A scoping review

PurposeFrailty and falls are two major health challenges in older adults, but little is known about their levels and interactions in community-dwelling older adults in sub-Saharan Africa. The purpose of this scoping review was to map the literature on frailty and falls with respect to their definitions, measurement methods, associated factors, and interactions in this setting. MethodsA systematic search of eight databases and four other relevant sources was performed with no language restriction using combinations of the keywords ‘frailty’, ‘older adults’, ‘falls’ and ‘Africa’ and their synonyms. ResultsThirty-six studies from nine countries in the sub-region met the inclusion criteria. The average age for participant inclusion in the studies was 50 years. The Frailty Phenotype and the Frailty Index were the primary assessment methods used, yielding frailty prevalence rates ranging from 5.4 % to 17.4 % and 20.6 % to 60.0 %, respectively. Fall prevalence ranged from 20.8 % to 55.1 %, while recurrent falls were reported in 11.0 % to 24.6 % of cases. Comorbidities/multimorbidity and increasing age were the most reported clinical and socio-demographic factors associated with frailty. Low functional status and being female were the primary factors associated with falls. Conclusions and recommendationsIn sub-Saharan Africa, there appears to be a high prevalence of frailty and falls in a relatively young cohort of older adults. Future studies should focus on developing frailty definitions and assessment methods that are culturally appropriate in this setting.

Associations of actigraph sleep characteristics with blood pressure among older adults

ObjectivesMany studies have examined links between sleep and blood pressure, with mixed findings, mostly using self-reported sleep data and cross-sectional designs. We examined whether actigraph-estimated sleep characteristics are associated with concurrent blood pressure or 5-year blood pressure change in a national cohort of older adults (National Social Life, Health and Aging Project), and whether these associations differ by hypertension medication use. MethodsSubjects were 669 older adults (62-90years), 471 with 5-year follow-up data. Sleep characteristics were duration (linear plus quadratic terms); sleep percentage; and categorical onset, midpoint, and waking times. Multivariable linear models adjusted for age, race, gender, obesity, smoking, daytime napping, and hypertension medication use. Interactions between sleep characteristics and hypertension medication were tested among the 401 subjects with consistent hypertension medication status over time. ResultsWe found U-shaped cross-sectional and longitudinal relationships between duration and blood pressure, with shorter and longer sleep times associated with higher blood pressure. Later onset times were cross-sectionally associated with higher systolic blood pressure, while earlier onset times were longitudinally associated with systolic blood pressure increase. Midpoint, wake time, and sleep percentage were not significantly associated with blood pressure. Significant interaction terms suggested hypertension medications attenuated associations of sleep onset and wake time with diastolic blood pressure. ConclusionsThese results with actigraph-estimated parameters confirm some, but not all, associations reported from research based on self-reported sleep data. Our findings are consistent with recommended intermediate sleep durations for cardiovascular health and suggest hypertension medication use may attenuate some associations between sleep timing and blood pressure.

Cognitive performance trends among European older adults: exploring variations across cohorts, gender, and educational levels (2007–2017)

BackgroundThis study explores recent cohort trends in cognitive performance among older Europeans from 2007 to 2017, addressing three key questions: (1) Did cognitive performance improve universally and across the performance distribution during this period? (2) Did these improvements occur across educational levels and for both men and women? (3) Can established risk factors explain these performance gains?MethodsUsing data from the Survey of Health, Ageing and Retirement in Europe (SHARE) across 12 European countries, we assessed immediate recall, delayed recall, and verbal fluency in individuals aged 60 to 94 in both 2007 and 2017 (n = 32 773). Differences between the two time points were estimated with linear mixed effects regression models and quantile regression.ResultsCognitive performance improved in all age groups, across educational levels, and for both men and women between 2007 and 2017. Notably, improvements were more pronounced at the upper end of the performance distribution for delayed recall and verbal fluency. Education explained approximately 20% of the observed improvements. Risk factors did not explain the observed improvements.ConclusionsEuropean cohorts of both younger-old and older adults continue to exhibit improvements in cognitive performance. Variation in the size of the cohort improvements across the performance distributions in delayed recall and in verbal fluency may contribute to growing inequalities in cognitive outcomes. Future research should further investigate the potential heterogeneity in cognitive performance gains.Trial registrationNot applicable.

Pre-Frailty and Frailty in Hospitalized Older Adults: A Comparison Study in People with and without a History of Cancer in an Acute Medical Unit.

A prospective observational study was conducted in a cohort of older adults ≥65 years (n = 329), admitted to the acute medical unit (AMU) of a tertiary hospital, to describe and compare characteristics including frailty status and clinical outcomes. Multivariable models compared older adults with and without a history of cancer to determine characteristics associated with frailty and pre-frailty. An adjusted Poisson regression model was used to compare the length of hospital stay (LOS) between the two groups. About one-fifth (22%) of the cohort had a history of cancer. The most common cancer types were prostate (n = 20), breast (n = 13), lung (n = 8) and gastrointestinal (n = 8). There was no difference in the prevalence of pre-frailty/frailty among patients with or without a history of cancer (58% vs. 57%, p > 0.05). Pre-frailty/frailty was associated with polypharmacy (OR 8.26, 95% CI: 1.74 to 39.2) and malnutrition (OR 8.91, 95% CI: 2.15 to 36.9) in patients with a history of cancer. Adjusted analysis revealed that the risk of having a longer LOS was 24% higher in older adults with a history of cancer than those without (IRR 1.24, 95% CI 1.10 to 1.41, p < 0.001). Clinicians in the AMU should be aware that older adults with a history of cancer have a higher risk of a longer LOS compared to those without.

Continuous glucose monitoring (CGM) for 308 older-age participants in an English birth cohort: variability and correlates

Introduction &amp; BackgroundEpochs of hyperglycaemia and hypoglycaemia may each increase risk of common chronic diseases and impair both cognitive and physical function even in people without diabetes. Older people may have greater frequency of adverse glycaemic excursions, partly due to disordered autonomic function and sleep quality. Data for older, non-diabetic people are however scant. Objectives &amp; Approach1) To describe blood glucose variability (completed) and 2) its socio-demographic and lifestyle correlates in a predominantly non-diabetic cohort of older adults (planned). Participants were recruited during 2021-2023 from an English birth cohort (the 1946 National Survey for Health and Development Study). They wore a continuous glucose monitor (Freestyle libre Abbott), which measured circulating glucose four times/hour, for seven days. Summary statistics and time outside range (4.4-7.8mmol/L) were calculated. Further information on glycaemic excursions and day-to-day variability will be gleaned using the R “iglu” package. For all CGM summary and excursion measures, future analyses will investigate: associations with HbA1c, socio-demographics, body composition, physical activity, diet and alcohol use. Results will be stratified by sleep/ wake time periods estimated from simultaneous actigraphy (Philips Actiwatch Spectrum Plus). Sensitivity analyses will exclude people taking hypo/ hyperglycaemic medications and those with diabetes. Relevance to Digital FootprintsDerived summary measures can be used by future studies to give insights into glycaemic variability as a population-level risk factor. This work will bring together multiple data sources, i.e. from CGM, actigraphy and baseline cohort data. ResultsParticipants were aged 75-76 years, 45% female and 10% had diagnosed diabetes; median (IQR) BMI was 26.8 (24.6-29.2) kg/m2. CGM data from 308 participants was collected, for a median (IQR) of 6.9 (6.7-7.6) days. Average glucose over the recording period was 5.7mmol/L (5.3-6.2mmol/L), standard deviation was 1.0mmol/L (0.8-1.3mmol/L), time outside range was 12.8% (6.2-24.7%) and 16% of participants spent ≥1 hour/day above and ≥1 hour/day below range. Conclusions &amp; ImplicationsCGM was feasible for this cohort of older adults, and demonstrated high levels of time outside range for a predominantly non-diabetic group. Future analysis will determine whether enhanced characterisation of glycaemic variability is a potentially more accurate tool for predicting future disease risk than isolated glucose measurements.

Validation of the Health Assessment Tool (HAT) based on four aging cohorts from the Swedish National study on Aging and Care

BackgroundAs global aging accelerates, routinely assessing the functional status and morbidity burden of older patients becomes paramount. The aim of this study is to assess the validity of the comprehensive clinical and functional Health Assessment Tool (HAT) based on four cohorts of older adults (60 + years) from the Swedish National study on Aging and Care (SNAC) spanning urban, suburban, and rural areas.MethodsThe HAT integrates five health indicators (gait speed, global cognition, number of chronic diseases, and basic and instrumental activities of daily living), providing an individual-level score between 0 and 10. The tool was constructed using nominal response models, first separately for each cohort and then in a harmonized dataset. Outcomes included all-cause mortality over a maximum follow-up of 16 years and unplanned hospital admissions over a maximum of 3 years of follow-up. The predictive capacity was assessed through the area under the curve (AUC) using logistic regressions. For time to death, Cox regressions were performed, and Harrell’s C-indices were reported. Results from the four cohorts were pooled using individual participant data meta-analysis and compared with those from the harmonized dataset.ResultsThe HAT demonstrated high predictive capacity across all cohorts as well as in the harmonized dataset. In the harmonized dataset, the AUC was 0.84 (95% CI 0.81–0.87) for 1-year mortality, 0.81 (95% CI 0.80–0.83) for 3-year mortality, 0.80 (95% CI 0.79–0.82) for 5-year mortality, 0.69 (95% CI 0.67–0.70) for 1-year unplanned admissions, and 0.69 (95% CI 0.68–0.70) for 3-year unplanned admissions. The Harrell’s C for time-to-death throughout 16 years of follow-up was 0.75 (95% CI 0.74–0.75).ConclusionsThe HAT is a highly predictive, clinically intuitive, and externally valid instrument with potential for better addressing older adults’ health needs and optimizing risk stratification at the population level.

Associations between toxicity-weighted concentrations and dementia risk: Results from the Cardiovascular Health Cognition Study

BackgroundAir pollution is a modifiable risk factor for dementia. Yet, studies on specific sources of air pollution (i.e., toxic chemical emissions from industrial facilities) and dementia risk are scarce. We examined associations between toxicity-weighted concentrations of industrial pollution and dementia outcomes among a large, multi-site cohort of older adults. MethodsParticipants (n = 2770) were ≥ 65 years old (Mean = 75.3, SD = 5.1 years) from the Cardiovascular Health Cognition Study (1992–1999). Toxicity-weighted concentrations were estimated using the Risk Screening Environmental Indicator (RSEI) model which incorporates total reported chemical emissions with toxicity, fate, and transport models. Estimates were aggregated to participants' baseline census tract, averaged across 1988–1992, and log2-transformed. Dementia status was clinically adjudicated in 1998–1999 and categorized by subtype (Alzheimer's, vascular, mixed). We assessed whether RSEI-estimated toxicity-weighted concentrations were associated with 1) odds of prevalent dementia and 2) incident dementia risk by subtype. ResultsAfter adjusting for individual and census-tract level covariates, a doubling in toxicity-weighted concentrations was associated with 9 % higher odds of prevalent dementia (OR = 1.09, 95 % CI: 1.00, 1.19). In discrete-time survival models, each doubling in toxicity-weighted concentrations was associated with a 16 % greater hazard of vascular dementia (HR = 1.16, 95 % CI: 1.01, 1.34) but was not significantly associated with all-cause, Alzheimer's disease, or mixed dementia (p's > 0.05). DiscussionLiving in regions with higher toxicity-weighted concentrations was associated with higher odds of prevalent dementia and a higher risk of incident vascular dementia in this large, community-based cohort of older adults. These findings support the need for additional studies to examine whether toxic chemical emissions from industrial and federal facilities may be a modifiable target for dementia prevention.

Long-term outcomes of older adults with acute COVID-19 following inpatient geriatric rehabilitation: a prospective cohort study from the Republic of Ireland

BackgroundThere is a paucity of research reporting the long-term outcomes of older adults who have completed geriatric rehabilitation following COVID-19.AimThe primary aim of this study is to describe the long-term functional outcomes of a cohort of older adults with acute COVID-19 who have completed inpatient geriatric rehabilitation.MethodsThis is a subgroup analysis of Irish data from a pan-European prospective cohort study. Functional ability, patient reported symptoms, and quality of life were measured using the Barthel index, the COVID-19 Yorkshire Rehabilitation Screen, and the EQ-5D-5L, respectively.ResultsThirty patients enrolled in the study. The rate of mortality was 23.3% at 6 months after discharge from rehabilitation. Patients achieved a return to pre-admission functional ability but reported a significant increase in patient reported symptoms and their quality of life did not return to pre-admission levels when assessed at 6 months after discharge from rehabilitation.ConclusionsMultidisciplinary rehabilitation for older adults with acute COVID-19 infection can assist patients to return to their premorbid functional ability. On discharge from rehabilitation, ongoing follow-up of older adults is recommended to assist them to negotiate and manage ongoing symptomatology such as breathlessness or fatigue.

Lower motor performance is linked with poor sleep quality, depressive symptoms, and grey matter volume alterations.

Motor performance (MP) is essential for functional independence and well-being, particularly in later life. However, the relationship between behavioural aspects such as sleep quality and depressive symptoms, which contribute to MP, and the underlying structural brain substrates of their interplay remains unclear. This study used three population-based cohorts of younger and older adults (n=1,950) from the Human Connectome Project-Young Adult (HCP-YA), HCP-Aging (HCP-A), and enhanced Nathan Kline Institute-Rockland sample (eNKI-RS). Several canonical correlation analyses were computed within a machine learning framework to assess the associations between each of the three domains (sleep quality, depressive symptoms, grey matter volume (GMV)) and MP. The HCP-YA analyses showed progressively stronger associations between MP and each domain: depressive symptoms (unexpectedly positive, r=0.13, SD=0.06), sleep quality (r=0.17, SD=0.05), and GMV (r=0.19, SD=0.06). Combining sleep and depressive symptoms significantly improved the canonical correlations (r=0.25, SD=0.05), while the addition of GMV exhibited no further increase (r=0.23, SD=0.06). In young adults, better sleep quality, mild depressive symptoms, and GMV of several brain regions were associated with better MP. This was conceptually replicated in young adults from the eNKI-RS cohort. In HCP-Aging, better sleep quality, fewer depressive symptoms, and increased GMV were associated with MP. Robust multivariate associations were observed between sleep quality, depressive symptoms and GMV with MP, as well as age-related variations in these factors. Future studies should further explore these associations and consider interventions targeting sleep and mental health to test the potential effects on MP across the lifespan.

Post-contrast CT liver attenuation alone is superior to the liver-spleen difference for identifying moderate hepatic steatosis.

To assess the diagnostic performance of post-contrast CT for predicting moderate hepatic steatosis in an older adult cohort undergoing a uniform CT protocol, utilizing hepatic and splenic attenuation values. A total of 1676 adults (mean age, 68.4 ± 10.2 years; 1045M/631F) underwent a CT urothelial protocol that included unenhanced, portal venous, and 10-min delayed phases through the liver and spleen. Automated hepatosplenic segmentation for attenuation values (in HU) was performed using a validated deep-learning tool. Unenhanced liver attenuation < 40.0 HU, corresponding to > 15% MRI-based proton density fat, served as the reference standard for moderate steatosis. The prevalence of moderate or severe steatosis was 12.9% (216/1676). The diagnostic performance of portal venous liver HU in predicting moderate hepatic steatosis (AUROC = 0.943) was significantly better than the liver-spleen HU difference (AUROC = 0.814) (p < 0.001). Portal venous phase liver thresholds of 80 and 90 HU had a sensitivity/specificity for moderate steatosis of 85.6%/89.6%, and 94.9%/74.7%, respectively, whereas a liver-spleen difference of -40 HU and -10 HU had a sensitivity/specificity of 43.5%/90.0% and 92.1%/52.5%, respectively. Furthermore, livers with moderate-severe steatosis demonstrated significantly less post-contrast enhancement (mean, 35.7 HU vs 47.3 HU; p < 0.001). Moderate steatosis can be reliably diagnosed on standard portal venous phase CT using liver attenuation values alone. Consideration of splenic attenuation appears to add little value. Moderate steatosis not only has intrinsically lower pre-contrast liver attenuation values (< 40 HU), but also enhances less, typically resulting in post-contrast liver attenuation values of 80 HU or less. Moderate steatosis can be reliably diagnosed on post-contrast CT using liver attenuation values alone. Livers with at least moderate steatosis enhance less than those with mild or no steatosis, which combines with the lower intrinsic attenuation to improve detection. The liver-spleen attenuation difference is frequently utilized in routine practice but appears to have performance limitations. The liver-spleen attenuation difference is less effective than liver attenuation for moderate steatosis. Moderate and severe steatosis can be identified on standard portal venous phase CT using liver attenuation alone.

Hypothalamic MRI-derived microstructure is associated with neurocognitive aging in humans

The hypothalamus regulates homeostasis across the lifespan and is emerging as a regulator of aging. In murine models, aging-related changes in the hypothalamus, including microinflammation and gliosis, promote accelerated neurocognitive decline. We investigated relationships between hypothalamic microstructure and features of neurocognitive aging, including cortical thickness and cognition, in a cohort of community-dwelling older adults (age range 65–97 years, n=124). Hypothalamic microstructure was evaluated with two magnetic resonance imaging diffusion metrics: mean diffusivity (MD) and fractional anisotropy (FA), using a novel image processing pipeline. Hypothalamic MD was cross-sectionally positively associated with age and it was negatively associated with cortical thickness. Hypothalamic FA, independent of cortical thickness, was cross-sectionally positively associated with neurocognitive scores. An exploratory analysis of longitudinal neurocognitive performance suggested that lower hypothalamic FA may predict cognitive decline. No associations between hypothalamic MD, age, and cortical thickness were identified in a younger control cohort (age range 18–63 years, n=99). To our knowledge, this is the first study to demonstrate that hypothalamic microstructure is associated with features of neurocognitive aging in humans.

An assessment of the mediating role of hypertension in the effect of long-term air pollution exposure on dementia.

Growing evidence links air pollution exposure to the risk of dementia. We hypothesized that hypertension may partially mediate this effect. We previously documented an association between air pollution and dementia in the Ginkgo Evaluation of Memory Study, a randomized, placebo-controlled trial of 3069 adults ≥75 years across four US sites who were evaluated for dementia every 6 months from 2000-2008. We utilized a two-stage regression approach for causal mediation analysis to decompose the total effect of air pollution on dementia into its natural direct and indirect effect through prevalent hypertension. Exposure to air pollution in the 10 or 20 years before enrollment was assigned using estimates from fine-scale spatial-temporal models for PM2.5, PM10, and NO2. We used Poisson regression models for hypertension and Cox proportional hazard models for time-to-incident all-cause dementia, adjusting for a priori confounders. Participants were free of mild cognitive impairment at baseline (n = 2564 included in analyses); 69% had prevalent hypertension at baseline. During follow-up, 12% developed all-cause dementia (Alzheimer's disease [AD] = 212; vascular dementia with or without AD [VaD/AD mixed] = 97). We did not find an adverse effect of any air pollutant on hypertension. Hypertension was associated with VaD/AD mixed (HR, 1.92 [95% CI = 1.14, 3.24]) but not AD. We did not observe mediation through hypertension for the effect of any pollutant on dementia outcomes. The lack of mediated effect may be due to other mechanistic pathways and the minimal effect of air pollution on hypertension in this cohort of older adults.