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Disturbances in the brain's capacity to meet its energy demand increase the risk of synaptic loss, neurodegeneration, and cognitive decline. Nutritional and metabolic interventions that target metabolic pathways combined with diagnostics to identify deficits in cerebral bioenergetics may therefore offer novel therapeutic potential for Alzheimer's disease (AD) prevention and management. Many diet-derived natural bioactive components can govern cellular energy metabolism but their effects on brain aging are not clear. This review examines how nutritional metabolism can regulate brain bioenergetics and mitigate AD risk. We focus on leading mechanisms of cerebral bioenergetic breakdown in the aging brain at the cellular level, as well as the putative causes and consequences of disturbed bioenergetics, particularly at the blood-brain barrier with implications for nutrient brain delivery and nutritional interventions. Novel therapeutic nutrition approaches including diet patterns are provided, integrating studies of the gut microbiome, neuroimaging, and other biomarkers to guide future personalized nutritional interventions.

Although clinicians caring for persons at the end of life recognize the phenomenon of paradoxical/terminal lucidity, systematic evidence is scant. The current pilot study aimed to develop a structured interview instrument for health care professionals to report lucidity. A questionnaire measuring lucidity length, degree, content, coinciding circumstances, and time from episode to death was expanded to include time of day, expressive and receptive communication, and speech during the month prior to and during the event. Thirty-three interviews were conducted; 73% of participants reported ever witnessing paradoxical lucidity. Among 29 events reported, 31% lasted several days, 20.7% lasted 1 day, and 24.1% lasted Journal of Gerontological Nursing, 49 (1), 18–26.]

Age-related macular degeneration (AMD) is a leading cause of blindness with no treatment available for early stages. Retrospective studies have shown an association between metformin and reduced risk of AMD.To investigate the association between metformin use and age-related macular degeneration (AMD).The Diabetes Prevention Program Outcomes Study is a cross-sectional follow-up phase of a large multicenter randomized clinical trial, Diabetes Prevention Program (1996-2001), to investigate the association of treatment with metformin or an intensive lifestyle modification vs placebo with preventing the onset of type 2 diabetes in a population at high risk for developing diabetes. Participants with retinal imaging at a follow-up visit 16 years posttrial (2017-2019) were included. Analysis took place between October 2019 and May 2022.Participants were randomly distributed between 3 interventional arms: lifestyle, metformin, and placebo.Prevalence of AMD in the treatment arms.Of 1592 participants, 514 (32.3%) were in the lifestyle arm, 549 (34.5%) were in the metformin arm, and 529 (33.2%) were in the placebo arm. All 3 arms were balanced for baseline characteristics including age (mean [SD] age at randomization, 49 [9] years), sex (1128 [71%] male), race and ethnicity (784 [49%] White), smoking habits, body mass index, and education level. AMD was identified in 479 participants (30.1%); 229 (14.4%) had early AMD, 218 (13.7%) had intermediate AMD, and 32 (2.0%) had advanced AMD. There was no significant difference in the presence of AMD between the 3 groups: 152 (29.6%) in the lifestyle arm, 165 (30.2%) in the metformin arm, and 162 (30.7%) in the placebo arm. There was also no difference in the distribution of early, intermediate, and advanced AMD between the intervention groups. Mean duration of metformin use was similar for those with and without AMD (mean [SD], 8.0 [9.3] vs 8.5 [9.3] years; P = .69). In the multivariate models, history of smoking was associated with increased risks of AMD (odds ratio, 1.30; 95% CI, 1.05-1.61; P = .02).These data suggest neither metformin nor lifestyle changes initiated for diabetes prevention were associated with the risk of any AMD, with similar results for AMD severity. Duration of metformin use was also not associated with AMD. This analysis does not address the association of metformin with incidence or progression of AMD.

IntroductionThe burden of Alzheimer’s disease (AD) and AD-related dementias (ADRD) is increasing nationally and globally, with disproportionate impacts on lower-income, lower education and systematically marginalised older adults. Presence of inequalities in neighbourhood factors (eg, social context, physical and built environments) may affect risk of cognitive decline and be key for intervening on AD/ADRD disparities at the population level. However, existing studies are limited by a dearth of longitudinal, detailed neighbourhood measures linked to rich, prospective cohort data. Our main objective is to identify patterns of neighbourhood change related to prevalence of—and disparities in—cognitive decline and dementia.Methods and analysesWe describe the process of collecting, processing and linking extensive neighbourhood data to the Multi-Ethnic Study of Atherosclerosis (MESA), creating a 25+ years dataset. Within the MESA parent study, the MESA Neighborhoods and Aging cohort study will characterise dynamic, longitudinal neighbourhood social and built environment variables relevant to cognition for residential addresses of MESA participants. This includes administering new surveys, expanding residential address histories, calculating new measures derived from spatial data and implementing novel deep learning algorithms on street-level imagery. Applying novel statistical techniques, we will examine associations of neighbourhood environmental characteristics with cognition and clinically relevant AD/ADRD outcomes. We will investigate determinants of disparities in outcomes by socioeconomic position and race/ethnicity and assess the contribution of neighbourhood environments to these disparities. This project will provide new evidence about pathways between neighbourhood environments and cognitive outcomes, with implications for policies to support healthy ageing.Ethics and disseminationThis project was approved by the University of Washington and Drexel University Institutional Review Boards (protocols #00009029 and #00014523, and #180900605). Data will be distributed through the MESA Coordinating Center. Findings will be disseminated in peer-reviewed scientific journals, briefs, presentations and on the participant website.

To assess associations that endogenous estradiol and testosterone levels have with cognitive function in older adults with Type 2 diabetes mellitus (T2DM).We use data from the Look AHEAD clinical trial of behavioral weight loss. Endogenous estradiol and total testosterone levels were determined using stored serum from 996 individuals, mean age 69 years, at two times (averaging 4 years apart) during years 8-18 of follow-up. One to four standardized assessments of attention, executive function, memory, and verbal fluency were collected during this follow-up. Mixed effects models and multiple imputation were used to assess associations that estradiol and total testosterone levels had with body mass index and cognitive function.Estradiol levels were not associated with cognitive function in either sex. Total testosterone levels were not associated with cognitive function in women, but greater total testosterone levels were associated with better verbal fluency in men (p 0.001), most strongly among those carrying the APOE-e4 allele (interaction p = 0.02). The weight loss intervention left a legacy of relatively lower cognitive functioning among women, which was not mediated by current levels of sex hormones.Behavioral weight loss intervention does not affect cognitive functioning through mechanisms related to estradiol or testosterone.gov Identifier: NCT00017953.

The 10-year intensive lifestyle intervention (ILI) of the Look AHEAD study left a legacy of relative deficits in cognitive function among participants who entered the clinical trial with obesity or a history of cardiovascular disease. We hypothesized that altered levels of two weight-sensitive proangiogenic cytokines, leptin and vascular endothelial growth factor (VEGF), accounted for this concerning finding.Serum leptin and VEGF concentrations were determined in 1,279 Look AHEAD participants at baseline, proximal to cessation of the interventions (Epoch 1), and an average of 4 years later (Epoch 2). Up to four standardized assessments of attention, executive function, and memory were collected during follow-up. Mixed effects models were used to assess relative differences in leptin and VEGF concentrations between intervention groups and whether these accounted for changes in cognitive composite scores.ILI and diabetes support and education differences in VEGF, but not leptin, concentrations varied depending on baseline history of cardiovascular disease and obesity, but neither leptin nor VEGF concentrations accounted for the relative decrements in cognitive function in participants assigned to ILI.Alterations in two weight-sensitive proangiogenic cytokines did not account for the long-term adverse effects of ILI on cognitive function among adults with diabetes and either obesity or cardiovascular disease.

IntroductionSex hormone binding globulin (SHBG) levels are reported to be inversely associated with diabetes risk. It is unknown whether diabetes prevention interventions increase SHBG and whether resultant changes in SHBG affect diabetes risk. The purpose of this analysis was to determine whether intensive lifestyle intervention (ILS) or metformin changed circulating SHBG and if resultant changes influenced diabetes risk in the Diabetes Prevention Program (DPP).Research design and methodsThis is a secondary analysis from the DPP (1996–2001), a randomized trial of ILS or metformin versus placebo on diabetes risk over a mean follow-up of 3.2 years. The DPP was conducted across 27 academic study centers in the USA. Men, premenopausal and postmenopausal women without hormone use in the DPP were evaluated. The DPP included overweight/obese persons with elevated fasting glucose and impaired glucose tolerance. Main outcomes measures were changes in SHBG levels at 1 year and risk of diabetes over 3 years.ResultsILS resulted in significantly higher increases (postmenopausal women: pConclusionsLifestyle intervention may be associated with favorable changes in circulating SHBG, which is largely due to changes in adiposity. Changes in circulating SHBG do not independently predict reductions in diabetes incidence.

Type 2 diabetes is linked with cognitive dysfunction and dementia in epidemiological studies, but these observations are limited by lack of data on the exact timing of diabetes onset. We investigated diabetes, dysglycaemia, and cognition in the Finnish Diabetes Prevention Study, in which the timing and duration of diabetes are well documented.The Finnish Diabetes Prevention Study comprised middle-aged, overweight participants with impaired glucose tolerance but no diabetes at baseline (n = 522), randomized to lifestyle intervention or a control group. After an intervention period (mean duration 4 years) and follow-up (additional 9 years), cognitive assessment with the CERAD test battery and Trail Making Test A (TMT) was executed twice within a 2-year interval. Of the 364 (70%) participants with cognitive assessments, 171 (47%) had developed diabetes.Cognitive function did not differ between those who developed diabetes and those who did not. Lower mean 2-h glucose at an oral glucose tolerance test (OGTT) and HbA1C during the intervention period predicted better performance in the TMT (p = 0.012 and 0.024, respectively). Those without diabetes or with short duration of diabetes improved in CERAD total score between the two assessments (p = 0.001) whereas those with long duration of diabetes did not (p = 0.844).Better glycemic control among persons with baseline impaired glucose tolerance predicted better cognitive performance 9 years later in this secondary analysis of the Finnish Diabetes Prevention Study population. In addition, learning effects in cognitive testing were not evident in people with long diabetes duration. Copyright © 2015 John WileySons, Ltd.

Background: Type 2 diabetes mellitus (DM) results from insulin resistance (IR), pancreatic β-cell dysfunction, or both. We hypothesized that risk factors could differ for DM preceded predominantly by IR, β-cell dysfunction, or both. This hypothesis is particularly important for older adults, in whom β-cell dysfunction may be relatively common. Methods: During 18 years of follow-up among 3,899 older adults free of DM (mean±sd age =73.0±5.8), we identified 274 incident DM cases by DM medication use, fasting glucose (≥126 mg/dL), or 2-hour post-challenge glucose (≥200 mg/dL), for whom homeostatic model assessments for IR (HOMA-IR) and β-cell function (HOMA-B) were assessed after baseline and before DM diagnosis. Using median cutoffs of the follow-up HOMA-IR and HOMA-B, we subclassified incident DM into DM preceded by IR only (n=112), β-cell dysfunction only (n=70), or both (n=77). Using multivariate competing-risk Cox models, we tested whether DM risk factors were differentially associated with risk of each DM subclass. Results: Elevated triglyceride levels (≥150 mg/dL) and impaired fasting glucose (100-125 mg/dL) were each positively associated with DM, irrespective of the DM subclass. Other DM risk factors of older age, overweight, obesity, low HDL cholesterol, and hypertension had substantially varying relationships with risk of different DM subclasses (p Conclusions: Among older adults, some DM risk factors differ substantially depending on HOMA-IR or HOMA-B subclassification. These findings support our hypothesis of heterogeneity in incident DM, especially among older adults.

Introduction: Gait speed is associated with multiple adverse outcomes of aging. White matter hyperintensities (WMH) on magnetic resonance imaging (MRI) have been associated with gait speed, though few studies have examined changes in gait speed over time, regional localization of WMH, or enrolled participants community-based studies and in ethnic/racial minorities. We examined the association between a decline in gait speed and total and regional WMH volumes in a community-based study of aging. Methods: Participants were enrolled in the Washington Heights Inwood Columbia Aging Project (WHICAP), a cohort of Medicare recipients residing in Northern Manhattan. At enrollment participants underwent a comprehensive medical evaluation, as well as neuropsychological testing and assessment of gait speed via a 4 meter walk test. An MRI sub-study was started in 2004, at which time participants underwent a second gait speed measurement (mean 4.7 [SD=0.5] years apart). Odds ratios (OR) and 95% confidence intervals (CI) were calculated to examine the associations of large (defined as one standard deviation above the age-expected mean) WMH volume and regional WMH volumes (as a continuous measure) with the primary outcome (transition from normal to abnormal gait speed, defined as < 0.4 meters/second) using logistic regression. Analyses were adjusted for socio-demographic factors, clinical history of stroke, hypertension, diabetes, body mass index, the presence of mild cognitive impairment or dementia, the length of time between the two physical performance measures, and the initial gait speed measure. Results: A total of 758 participants in WHICAP underwent MRI and two measures of gait speed. At the time of MRI the mean age was 80.3 (SD=5.6) and 114 (14.4%) had a large WMH volume. Large WMH volume was associated with a transition to an abnormal gait speed between the two visits (adjusted OR 3.09, 95% CI=1.21-7.93). Total frontal WMH volume (adjusted OR 1.06, 95%CI=0.93-1.20), or other regional volumes, were not associated with a transition to an abnormal gait speed between the two gait speed measurements. Conclusion: Total, but not regional, WMH are associated with slowing of gait over time. Modification of the known risk factors associated withWMH presents a potential strategy for the prevention of gait speed decline.

Hyperphosphorylated tau is the major component of paired helical filaments in neurofibrillary tangles found in Alzheimer's disease (AD) brains, and tau hyperphosphorylation is thought to be a critical event in the pathogenesis of the disease. The large majority of AD cases is late onset and sporadic in origin, with aging as the most important risk factor. Insulin resistance, impaired glucose tolerance, and diabetes mellitus (DM) are other common syndromes in the elderly also strongly age dependent, and there is evidence supporting a link between insulin dysfunction and AD. To investigate the possibility that insulin dysfunction might promote tau pathology, we induced insulin deficiency and caused DM in mice with streptozotocin (STZ). A mild hyperphosphorylation of tau could be detected 10, 20, and 30 d after STZ injection, and a massive hyperphosphorylation of tau was observed after 40 d. The robust hyperphosphorylation of tau was localized in the axons and neuropil, and prevented tau binding to microtubules. Neither mild nor massive tau phosphorylation induced tau aggregation. Body temperature of the STZ-treated mice did not differ from control animals during 30 d, but dropped significantly thereafter. No change in β-amyloid (Aβ) precursor protein (APP), APP C-terminal fragments, or Aβ levels were observed in STZ-treated mice; however, cellular protein phosphatase 2A activity was significantly decreased. Together, these data indicate that insulin dysfunction induced abnormal tau hyperphosphorylation through two distinct mechanisms: one was consequent to hypothermia; the other was temperature-independent, inherent to insulin depletion, and probably caused by inhibition of phosphatase activity.

To examine the association between intake of alcoholic beverages and risk of Alzheimer's disease (AD) and dementia associated with stroke (DAS) in a cohort of elderly persons from New York City.Cohort study.The Washington Heights Inwood-Columbia Aging Project.Nine hundred eighty community-dwelling individuals aged 65 and older without dementia at baseline and with data on alcohol intake recruited between 1991 and 1996 and followed annually.Intake of alcohol was measured using a semiquantitative food frequency questionnaire at baseline. Subjects were followed annually, and incident dementia was diagnosed using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria and classified as AD or DAS.After 4 years of follow-up, 260 individuals developed dementia (199 AD, 61 DAS). After adjusting for age, sex, apolipoprotein E (APOE)-epsilon 4 status, education, and other alcoholic beverages, only intake of up to three daily servings of wine was associated with a lower risk of AD (hazard ratio=0.55, 95% confidence interval=0.34-0.89). Intake of liquor, beer, and total alcohol was not associated with a lower risk of AD. Stratified analyses by the APOE-epsilon 4 allele revealed that the association between wine consumption and lower risk of AD was confined to individuals without the APOE-epsilon 4 allele.Consumption of up to three servings of wine daily is associated with a lower risk of AD in elderly individuals without the APOE epsilon-4 allele.