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AbstractAlzheimer disease (AD) is the most common type of dementia characterized by the progressive cognitive and social decline. Clinical drug targets have heavily focused on the amyloid hypothesis, with amyloid beta (Aβ), and tau proteins as key pathophysiologic markers of AD. However, no effective treatment has been developed so far, which prompts researchers to focus on other aspects of AD beyond Aβ, and tau proteins. Additionally, there is a mounting epidemiologic evidence that various environmental factors influence the development of dementia and that dementia etiology is likely heterogenous. In the past decades, new risk factors or potential etiologies have been widely studied. Here, we review several novel epidemiologic and clinical research developments that focus on sleep, hypoxia, diet, gut microbiota, and hearing impairment and their links to AD published in recent years. At the frontiers of AD research, these findings and updates could be worthy of further attention.

ObjectiveTo investigate whether dietary patterns (Mediterranean diet [MedDiet], Dietary Approaches to Stop Hypertension [DASH], and A Priori Diet Quality Score [APDQS]) during adulthood are associated with midlife cognitive performance.MethodsWe studied 2,621 Coronary Artery Risk Development in Young Adults (CARDIA) participants; 45% were black, 57% were female, and mean age was 25 ± 3.5 years at baseline (year 0). Mean diet scores were calculated from diet history at baseline, year 7, and year 20 (mean age 25, 32, and 45 years, respectively). Cognitive function was assessed at years 25 and 30 (mean age 50 and 55 years, respectively). Linear models were used to examine association between tertiles of diet score and change in composite cognitive function and cognitive z scores (verbal memory [Rey Auditory Verbal Learning Test], processing speed [Digit Symbol Substitution Test], and executive function [Stroop Interference test]) and the Montreal Cognitive Assessment (MoCA) at year 30.ResultsDASH was not associated with change in cognitive performance. Higher MedDiet and APDQS scores were associated with less decline in cognitive function (MedDiet: low -0.04, middle 0.03, high 0.03, p = 0.03; APDQS: low -0.04, middle -0.00, high 0.06, p < 0.01) and Stroop Interference (MedDiet: low 0.09, middle -0.06, high -0.03; APDQS: low 0.10, middle 0.01, high -0.09, both p < 0.01). Odds ratios (95% confidence interval) for poor global cognitive function (≥1 SD below mean MoCA score) comparing extreme tertiles of diet scores were 0.54 (0.39-0.74) for MedDiet, 0.48 (0.33-0.69) for APDQS, and 0.89 (0.68-1.17) for DASH.ConclusionGreater adherence to MedDiet and APDQS dietary patterns during adulthood was associated with better midlife cognitive performance. Additional studies are needed to define the combination of foods and nutrients for optimal brain health across the life course.

Aging is the biggest risk factor for the development of chronic diseases. Telomere length may represent one important mechanism by which dietary intake influences risk of age-related diseases; however, it is unknown which diet pattern is most strongly related to telomere length. We compared the relationships between 4 evidence-based diet quality indices and leukocyte telomere length in a nationally representative sample of healthy adults, and the extent to which these associations differed between men and women. Data on 4,758 adults aged 20-65 years with no prior diagnosis of major chronic disease were obtained from the 1999-2002 cycles of the National Health and Nutrition Examination Survey. Diet was assessed using one 24-hour dietary recall. After adjustment for sociodemographic and health characteristics, comparison of the top and bottom quintiles showed that higher Healthy Eating Index 2010 scores (β = 0.065, 95% confidence interval (CI): 0.018, 0.112; P-trend = 0.007), Alternate Healthy Eating Index 2010 scores (β = 0.054, 95% CI: 0.010, 0.097; P-trend = 0.007), Mediterranean Diet scores (β = 0.058, 95% CI: 0.017, 0.098; P-trend = 0.008), and Dietary Approaches to Stop Hypertension (DASH) scores (β = 0.052, 95% CI: 0.014, 0.090; P-trend = 0.007) were each associated with longer telomere length in women. These results may provide insight into the complex associations between optimal nutrition and longevity. Further investigation is needed to understand why associations were not observed in men.

ObjectivesTo evaluate the association between the Mediterranean diet (MedDiet) and the Mediterranean-DASH diet Intervention for Neurodegeneration Delay (MIND diet) and cognition in a nationally representative population of older U.S. adults.DesignPopulation-based cross-sectional study.SettingHealth and Retirement Study.ParticipantsCommunity-dwelling older adults (N = 5,907; mean age 67.8 ± 10.8).MeasurementsAdherence to dietary patterns was determined from food frequency questionnaires using criteria determined a priori to generate diet scores for the MedDiet (range 0-55) and MIND diet (range 0-15). Cognitive performance was measured using a composite test score of global cognitive function (range 0-27). Linear regression was used to compare cognitive performance according to tertiles of dietary pattern. Logistic regression was used to examine the association between dietary patterns and clinically significant cognitive impairment. Models were adjusted for age, sex, race, educational attainment, and other health and lifestyle covariates.ResultsParticipants with mid (odds ratio (OR) = 0.85, 95% confidence interval (CI) = 0.71-1.02, P = .08) and high (OR 0.65, 95% CI = 0.52-0.81, P

Objectives: The PROtein-enriched MEDiterranean diet to combat undernutrition and promote healthy neuroCOGnitive ageing in older adults (PROMED-COG) is a European project that investigates the role of nutritional status on neurocognitive ageing. This methodological paper describes the harmonization process of dietary data from four Italian observational studies (Pro.V.A., ILSA, BEST-FU, and NutBrain). Methods: Portion sizes and food frequency consumption within different food frequency questionnaires were retrospectively harmonized across the datasets on daily food frequency, initially analyzing raw data using the original codebook and establishing a uniform food categorization system. Individual foods were then aggregated into 27 common food groups. Results: The pooled cohort consisted of 9326 individuals (40–101 years, 52.4% female). BEST-FU recruited younger participants who were more often smokers and less physically active than those of the other studies. Dietary instruments varied across the studies differing in the number of items and time intervals assessed, but all collected dietary intake through face-to-face interviews with a common subset of items. The average daily intakes of the 27 food groups across studies varied, with BEST-FU participants generally consuming more fruits, vegetables, red meat, and fish than the other studies. Conclusions: Harmonization of dietary data presents challenges but allows for the integration of information from diverse studies, leading to a more robust and statistically powerful dataset. The study highlights the feasibility and benefits of data harmonization, despite inherent limitations, and sets the stage for future research into the effects of diet on cognitive health and aging. [ABSTRACT FROM AUTHOR]

Objectives Growing research suggests that food insecurity is associated with worse cognitive functioning; however, prospective studies are needed to examine food insecurity and dementia risk. Using longitudinal and nationally representative data, we examined the effects of food insecurity on dementia risk among older adults. Methods Data were from 3,232 adults (≥65 years) from the Panel Study of Income Dynamics. Food insecurity was assessed biennially using the U.S. Household Food Security Survey Module from 2015 to 2019. Probable dementia risk was assessed biennially using the Eight-Item Interview to Differentiate Aging and Dementia from 2017 to 2021. Inverse probability weighting and marginal structural models were used to account for the time-varying nature of food insecurity and sociodemographic and health confounders. Results After accounting for baseline and time-varying sociodemographic and health covariates, there was a 2-fold higher association between food insecurity and probable dementia risk (odds ratio 2.11, 95% confidence interval: 1.12–3.98). The results were robust to expanding the exposure to include marginal food security and the outcome to include informant-reported memory loss. Furthermore, there was no evidence of heterogeneity in the association of food insecurity and probable dementia risk by sex, race, and ethnicity, or participation in the Supplemental Nutrition Assistance program. Discussion Food insecurity is a modifiable social determinant of health. Interventions and policies are needed to reduce food insecurity and promote healthy aging for older adults. [ABSTRACT FROM AUTHOR]

Undernutrition may negatively impact cognitive function, but evidence of this relationship is not yet consolidated. Under the "PROtein enriched MEDiterranean diet to combat undernutrition and promote healthy neuroCOGnitive ageing" (PROMED-COG) project, we evaluated the association between undernutrition, and cognitive decline and incident dementia in older adults. Retrospective data harmonization was performed on three Italian population-based studies: the Italian Longitudinal Study of Ageing (ILSA), the Progetto Veneto Anziani (Pro.V.A.), and the Bollate Eye Study-Follow-Up (BEST-FU). The associations between undernutrition, operationalized using the Global Leadership Initiative on Malnutrition (GLIM) criteria, and decline on the Mini-Mental State Examination (MMSE) or dementia incidence follow-up were evaluated with Cox proportional hazard regression models. The pooled cohort comprised 9071 individuals (52% females) aged between 42 and 101 years. The prevalence of undernutrition at the baseline was 14.3%, significantly higher among females (15.4% vs 13%) and in older age, ranging from 3.5% in those aged <60 years to 28.8% in those 85+ years. Undernutrition was associated with both cognitive decline over a median 8.3-year follow-up (Hazard Ratio (HR) 1.20, 95% Confidence Interval (CI) 1.02–1.41, p = 0.028) and incidence of dementia over a median 8.6-year follow-up (HR = 1.57, 95%CI 1.01–2.43, p = 0.046). For cognitive decline, the association with undernutrition was more marked in males than females (HR = 1.36, 95%CI 1.05–1.77, p = 0.019 vs HR = 1.10, 95% CI 0.89–1.36, p = 0.375). Undernutrition is prevalent among older people and is associated with an increased risk of experiencing cognitive decline and dementia. The prevention and early identification of undernutrition could be an important nonpharmacologic strategy to counteract neurodegeneration. [ABSTRACT FROM AUTHOR]

There is still much to learn about the support required by postgraduate research students, across academic disciplines, to facilitate successful completion of a research degree. The primary aim of this study was to explore postgraduate medical science research students' perceptions of academic and mentoring support at different stages during their degree programme. A second aim was to explore the feasibility and acceptability of peer mentoring as a strategy to enhance student support in this population. A mixed method study design was used. Students first completed an online questionnaire, which was then supplemented with focus group discussion to explore emergent findings in greater depth. The main results indicated that the nature and quality of academic supervision support have a significant influence on research student training and development. 'Functional' and 'relationship development' concepts of supervisory styles were highlighted as important aspects to perceived support in this research population. The main facilitators to enhance academic support were effective communication, project planning and timely feedback. There was a high degree of acceptability for a peer mentoring programme as a complementary approach to enhance student support. Peer mentoring psychosocial functions such as friendship, counselling and career guidance were considered potentially beneficial to enhancing student support. Students also discussed peer coaching as central to their learning and research skill development. This work is a useful starting point to explore perceptions of research student support in the target population. Further work is required to develop strategies to enhance student support in academic practice.

Background Increasing fruit and vegetable (FV) consumption is associated with reduced cardiovascular disease risk in observational studies but with little evidence from randomised controlled trials (RCTs). The impact of concurrent pharmacological therapy is unknown. Objective To pool data from six RCTs to examine the effect of increasing FV intake on blood pressure (BP) and lipid profile, also exploring whether effects differed by medication use. Design Across trials, dietary intake was assessed by diet diaries or histories, lipids by routine biochemical methods and BP by automated monitors. Linear regression provided an estimate of the change in lipid profile or BP associated with a one portion increase in self-reported daily FV intake, with interaction terms fitted for medication use. Results The pooled sample included a total of 554 participants (308 males and 246 females). Meta-analysis of regression coefficients revealed no significant change in either systolic or diastolic BP per portion FV increase, although there was significant heterogeneity across trials for systolic BP (I 2 = 73%). Neither adjusting for change in body mass index, nor analysis according to use of anti-hypertensive medication altered the relationship. There was no significant change in lipid profile per portion FV increase, although there was a significant reduction in total cholesterol among those not on lipid-lowering therapy (P  < 0.05 after Bonferroni correction). Conclusion Pooled analysis of six individual FV trials showed no impact of increasing intake on BP or lipids, but there was a total cholesterol-lowering effect in those not on lipid-lowering therapy. [ABSTRACT FROM AUTHOR]

Food insecurity has been associated with adverse effects on physical health and well-being in both high and low-income countries, but effects on brain health are not clear. The purpose of this systematic review was to determine the relationship between food insecurity and important brain health outcomes in adults including depression, stroke, cognitive impairment and dementia. Electronic databases were searched to find studies which investigated relations between food insecurity and predefined brain health outcomes. Thirty studies met the inclusion criteria for review of which 23 were conducted in high income countries and seven in low- or middle-income countries. Most studies (n = 24) were cross-sectional, five were prospective and 1 was a case-control design. Seven studies reporting outcomes relating to cognitive performance and 24 relating to depression. No studies investigated relations between food insecurity and stroke or dementia. There was substantial heterogeneity in the populations studied as well as measures of food insecurity and outcomes which made comparisons between studies difficult. Overall, the findings highlighted that individuals who were food insecure had increased likelihood of depressive symptoms and poorer global cognition than those who were food secure. It is possible that social support and food aid programmes attenuate the effects of food insecurity on depressive symptoms. Future research is needed to determine whether interventions to alleviate food insecurity can benefit brain health in vulnerable populations. [ABSTRACT FROM AUTHOR]