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1.
Ageing Res Rev ; : 101044, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32171785

RESUMO

Physical activity has received substantial research attention due to its beneficial impact on cognition in ageing, particularly via the action of brain-derived neurotrophic factor (BDNF). It is well established that physical activity can elevate circulating levels of BDNF, and that BDNF has neurotrophic, neuroprotective and cognitively beneficial properties. Yet, practical implementation of this knowledge is limited by a lack of clarity on context and dose-effect. Against a shifting backdrop of gradually diminishing physical and cognitive capacity in normal ageing, the type, intensity, and duration of physical activity required to elicit elevations in BDNF, and more importantly, the magnitude of BDNF elevation required for detectable neuroprotection remains poorly characterised. The purpose of this review is to provide an overview of the association between physical activity, BDNF, and cognition, with a focus on clarifying the magnitude of these effects in the context of normative ageing. We discuss the implications of the available evidence for the design of physical activity interventions intended to promote healthy cognitive ageing.

2.
Sports Med ; 50(2): 403-413, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31529300

RESUMO

BACKGROUND: Besides physical activity as a target for dementia prevention, sedentary behaviour is hypothesized to be a potential target in its own right. The rising number of persons with dementia and lack of any effective treatment highlight the urgency to better understand these modifiable risk factors. Therefore, we aimed to investigate whether higher levels of sedentary behaviour are associated with reduced global cognitive functioning and slower cognitive decline in older persons without dementia. METHODS: We used five population cohorts from Greece, Australia, USA, Japan, and Singapore (HELIAD, PATH, SALSA, SGS, and SLAS2) from the Cohort Studies of Memory in an International Consortium. In a coordinated analysis, we assessed the relationship between sedentary behaviour and global cognitive function with the use of linear mixed growth model analysis (mean follow-up range of 2.0-8.1 years). RESULTS: Baseline datasets combined 10,450 older adults without dementia with a mean age range between cohorts of 66.7-75.1 years. After adjusting for multiple covariates, no cross-sectional association between sedentary behaviour and cognition was found in four studies. One association was detected where more sedentary behaviour was cross-sectionally linked to higher cognition levels (SLAS2, B = 0.118 (0.075; 0.160), P < 0.001). Longitudinally, there were no associations between baseline sedentary behaviour and cognitive decline (P > 0.05). CONCLUSIONS: Overall, these results do not suggest an association between total sedentary time and lower global cognition in older persons without dementia at baseline or over time. We hypothesize that specific types of sedentary behaviour may differentially influence cognition which should be investigated further. For now, it is, however, too early to establish undifferentiated sedentary time as a potential effective target for minimizing cognitive decline in older adults without dementia.

3.
Menopause ; 26(11): 1327-1333, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31567869

RESUMO

OBJECTIVES: The aim of the study was to determine lipid profile differences between premenopausal and postmenopausal women. METHODS: The present review used a meta-analytic approach. Sixty-six studies were included, which provided a total sample of 114,655 women consisting of 68,394 that were premenopausal and 46,261 that were postmenopausal. RESULTS: The main findings were that (1) lipoproteins were significantly higher in postmenopausal women compared to premenopausal women including triglycerides (0.27 mmol/L, 95% confidence interval, 0.22-0.31), total cholesterol (0.58, 0.50-0.65), low-density lipoprotein (0.45, 0.38-0.53), and total cholesterol to high-density lipoprotein levels (0.39, 0.16-0.62); (2) there was no difference in high-density lipoprotein levels between premenopausal and postmenopausal women (0.02, -0.00-0.04); and (3) the differences in lipid levels was partly attributable to the mean age difference between premenopausal and postmenopausal women. CONCLUSIONS: These findings are important as they provide precise estimates of lipid differences in women around menopause. Furthermore the results suggest that the unfavorable lipid profile that develops in postmenopausal women puts them at higher risk of cardiovascular disease such as heart disease and stroke if appropriate lifestyle/pharmacological interventions are not implemented.

4.
Neurobiol Aging ; 83: 86-94, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31585370

RESUMO

A key question for the design of clinical trials for Alzheimer's disease (AD) is whether the timing of conversion from mild cognitive impairment (MCI) to AD can be predicted. This is also an important question for the clinical management of MCI. This study aims to address this question by exploring the contribution of baseline brain volume and annual volume change, using Cox regression, in predicting the time to conversion. Individuals with MCI, who converted to AD (n = 198), reverted to normal (n = 38), or remained stable (n = 96) for at least five years, were included in this study. The results revealed that the volumes of all the brain areas considered were predictive of the time to conversion from MCI to AD. Annual change in volume was also predictive of the time to conversion but only when initial volumes were above a certain threshold. This is important because it suggests that reduction in atrophy rate, which is the outcome of some clinical trials, is not inevitably associated with delay in conversion from MCI to AD.

5.
PLoS Med ; 16(7): e1002853, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31335910

RESUMO

BACKGROUND: With no effective treatments for cognitive decline or dementia, improving the evidence base for modifiable risk factors is a research priority. This study investigated associations between risk factors and late-life cognitive decline on a global scale, including comparisons between ethno-regional groups. METHODS AND FINDINGS: We harmonized longitudinal data from 20 population-based cohorts from 15 countries over 5 continents, including 48,522 individuals (58.4% women) aged 54-105 (mean = 72.7) years and without dementia at baseline. Studies had 2-15 years of follow-up. The risk factors investigated were age, sex, education, alcohol consumption, anxiety, apolipoprotein E ε4 allele (APOE*4) status, atrial fibrillation, blood pressure and pulse pressure, body mass index, cardiovascular disease, depression, diabetes, self-rated health, high cholesterol, hypertension, peripheral vascular disease, physical activity, smoking, and history of stroke. Associations with risk factors were determined for a global cognitive composite outcome (memory, language, processing speed, and executive functioning tests) and Mini-Mental State Examination score. Individual participant data meta-analyses of multivariable linear mixed model results pooled across cohorts revealed that for at least 1 cognitive outcome, age (B = -0.1, SE = 0.01), APOE*4 carriage (B = -0.31, SE = 0.11), depression (B = -0.11, SE = 0.06), diabetes (B = -0.23, SE = 0.10), current smoking (B = -0.20, SE = 0.08), and history of stroke (B = -0.22, SE = 0.09) were independently associated with poorer cognitive performance (p < 0.05 for all), and higher levels of education (B = 0.12, SE = 0.02) and vigorous physical activity (B = 0.17, SE = 0.06) were associated with better performance (p < 0.01 for both). Age (B = -0.07, SE = 0.01), APOE*4 carriage (B = -0.41, SE = 0.18), and diabetes (B = -0.18, SE = 0.10) were independently associated with faster cognitive decline (p < 0.05 for all). Different effects between Asian people and white people included stronger associations for Asian people between ever smoking and poorer cognition (group by risk factor interaction: B = -0.24, SE = 0.12), and between diabetes and cognitive decline (B = -0.66, SE = 0.27; p < 0.05 for both). Limitations of our study include a loss or distortion of risk factor data with harmonization, and not investigating factors at midlife. CONCLUSIONS: These results suggest that education, smoking, physical activity, diabetes, and stroke are all modifiable factors associated with cognitive decline. If these factors are determined to be causal, controlling them could minimize worldwide levels of cognitive decline. However, any global prevention strategy may need to consider ethno-regional differences.


Assuntos
Cognição , Disfunção Cognitiva/etnologia , Grupos Étnicos/psicologia , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Disfunção Cognitiva/diagnóstico , Disfunção Cognitiva/psicologia , Comorbidade , Diabetes Mellitus/etnologia , Exercício , Feminino , Educação em Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Medição de Risco , Fatores de Risco , Fumar/efeitos adversos , Fumar/etnologia , Acidente Vascular Cerebral/etnologia
6.
Front Neuroendocrinol ; 54: 100769, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31176793

RESUMO

It is widely recognised that type 2 diabetes (T2D) represents a major disease burden but it is only recently that its role in neurodegeneration has attracted more attention. This research has shown that T2D is associated with impaired cerebral health, cognitive decline and dementia. However, the impact on the brain of progressive metabolic changes associated with the pre-clinical development of the disease is less clear. The aim of this review is to comprehensively summarise how the emergence of risk factors and co-morbid conditions linked to the development of T2D impact cerebral health. Particular attention is directed at characterising how normal but elevated blood glucose levels in individuals without T2D contribute to neurodegenerative processes, and how the main risk factors for T2D including obesity, physical activity and diet modulate these effects. Where available, evidence from the animal and human literature is contrasted, and sex differences in risk and outcomes are highlighted.

7.
J Neurosci Methods ; 323: 61-67, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31125590

RESUMO

BACKGROUND: Local shape complexity can be biologically meaningful as a marker of disease, trauma, or change in brain structure over time. Fractal dimensionality (FD) is currently the dominant measure of local shape complexity used in neuroimaging but its limitations are not well understood. NEW METHOD: Elliptical Fourier harmonic power requirement (HPR) may provide complementary information to FD. We benchmarked the performance of FD and HPR on a series of simulated shapes, systematically manipulating aspects of local shape complexity, and a series of clinical contours (glioma tumour cores and stroke lesions from the BRATS and ATLAS datasets). HPR was calculated as the point of 99.9% harmonic power. FD was calculated at six resolutions (8 × 8, 16 × 16, 32 × 32, 64 × 64, 128 × 128, and 256 × 256), by using an approach which computationally indexes the complexity of the shape boundary (i.e. the number of cells defining the contour) relative to the total grid size. RESULTS AND COMPARISON WITH EXISTING METHODS: PR and FD were moderately positively correlated (r ≈ 0.2 to 0.8 depending on shape properties), and both were sensitive to the frequency and amplitude of local complexity. FD was most biased by rotation, while HPR was more biased by global shape features such as deep invaginations. FD indicated an aggregate measure of complexity across the whole contour, while HPR indicated the point of highest complexity. CONCLUSIONS: The HPR index provides conceptually distinct local complexity information from the current FD standard. Future research will benefit from using these complementary measures.

8.
Am J Obstet Gynecol ; 221(5): 393-409.e50, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31034807

RESUMO

OBJECTIVE: Data: Fat mass has been shown to increase in aging women; however, the extent to which menopausal status mediates these changes remains unclear. The purpose of this review was to determine (1) how fat mass differs in quantity and distribution between premenopausal and postmenopausal women, (2) whether and how age and/or menopausal status moderates any observed differences, and (3) which type of fat mass measure is best suited to the detection of differences in fat mass between groups. STUDY: This review with metaanalyses is reported according to Metaanalysis of Observational Studies in Epidemiology guidelines. STUDY APPRAISAL AND SYNTHESIS METHODS: Studies (published up to May 2018) were identified via PubMed to provide fat mass measures in premenopausal and postmenopausal women. We included 201 cross-sectional studies in the metaanalysis, which provided a combined sample size of 1,049,919 individuals and consisted of 478,734 premenopausal women and 571,185 postmenopausal women. Eleven longitudinal studies were included in the metaanalyses, which provided a combined sample size of 2472 women who were premenopausal at baseline and postmenopausal at follow up. RESULTS: The main findings of this review were that fat mass significantly increased between premenopausal and postmenopausal women across most measures, which included body mass index (1.14 kg/m2; 95% confidence interval, 0.95-1.32 kg/m2), bodyweight (1 kg; 95% confidence interval, 0.44-1.57 kg), body fat percentage (2.88%; 95% confidence interval, 2.13-3.63%), waist circumference (4.63 cm; 95% confidence interval, 3.90-5.35 cm), hip circumference (2.01 cm; 95% confidence interval, 1.36-2.65 cm), waist-hip ratio (0.04; 95% confidence interval, 0.03-0.05), visceral fat (26.90 cm2; 95% confidence interval, 13.12-40.68), and trunk fat percentage (5.49%; 95% confidence interval, 3.91-7.06 cm2). The exception was total leg fat percentage, which significantly decreased (-3.19%; 95% confidence interval, -5.98 to -0.41%). No interactive effects were observed between menopausal status and age across all fat mass measures. CONCLUSION: The change in fat mass quantity between premenopausal and postmenopausal women was attributable predominantly to increasing age; menopause had no significant additional influence. However, the decrease in total leg fat percentage and increase in measures of central fat are indicative of a possible change in fat mass distribution after menopause. These changes are likely to, at least in part, be due to hormonal shifts that occur during midlife when women have a higher androgen (ie, testosterone) to estradiol ratio after menopause, which has been linked to enhanced central adiposity deposition. Evidently, these findings suggest attention should be paid to the accumulation of central fat after menopause, whereas increases in total fat mass should be monitored consistently across the lifespan.

9.
Alzheimers Dement ; 15(4): 581-589, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30826160

RESUMO

INTRODUCTION: Associations between the Mediterranean-DASH diet Intervention for Neurological Delay (MIND) diet and incidence of cognitive impairment have not been evaluated outside the United States. METHODS: We investigated MIND and Mediterranean diet relations with 12-year incidence of Alzheimer's disease/Vascular dementia (National Institute of Neurological Disorders criteria) and mild cognitive impairment (Winbald criteria) in the Personality and Total Health (PATH) Through Life cohort (n = 1220) set in Canberra, Australia: wave-1 2001-2002; wave-2 2005-2006; wave-3 2009-2010; and wave-4 2013-2014. MIND diet and two alternate Mediterranean diet scores were calculated from the baseline food frequency questionnaire responses. Higher dietary scores signified greater adherence. RESULTS: In adjusted logistic regression models, MIND diet (OR = 0.47, 95% CI 0.24, 0.91), but not Mediterranean diet, was associated with reduced odds of 12-year cognitive impairment. DISCUSSION: Preliminary evidence suggests that protective effects of the MIND diet are geographically generalizable. Additional prospective studies are needed in diverse samples to determine the relative effects of the MIND and the Mediterranean diets against cognitive decline.

10.
J Alzheimers Dis ; 70(s1): S63-S73, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30714954

RESUMO

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a major disease burden which accounts for 5% of all deaths globally, with most of those (>90%) occurring in lower to middle income countries (LMIC). It is also emerging as an important modifiable dementia risk factor. OBJECTIVE: To address the knowledge gap surrounding the nature of the associations between COPD, dementia, and mortality, and the geographical variation of those associations in LMIC. METHODS: Data from the 10/66 study surveying 15,394 participants (mean age 74 years, 62% female) across 8 countries was used to estimate the prevalence of self-reported COPD and its association with incident dementia and premature death. Proportional sub-hazards models using a cumulative incidence function were applied to identify the probability of incident dementia onset given the risk of premature death, with estimates pooled across countries via random effect meta-analysis. RESULTS: Over the 3-year follow-up, almost 10% of participants developed dementia and 14% were deceased. COPD was not significantly associated with dementia incidence except in Cuba. However, fully adjusted models indicated that individuals with COPD were at a 28% increased risk of premature death, a trend present across most countries when analyzed individually. CONCLUSION: The link between COPD and dementia is currently somewhat different and weaker in LMIC than in developed countries. This may be because premature death in the populations studied mask the development of clinical dementia. Given the global trend toward increased life expectancy, it is critical that the disease burden associated with COPD be addressed without delay if a further rise in dementia prevalence associated with COPD is to be avoided in LMIC.

11.
Alzheimer Dis Assoc Disord ; 33(2): 95-103, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30681434

RESUMO

PURPOSE: We investigated the association of the Australian National University Alzheimer's Disease Risk Index (ANU-ADRI) and an Alzheimer disease (AD) genetic risk score (GRS) with cognitive performance. METHODS: The ANU-ADRI (composed of 12 risk factors for AD) and GRS (composed of 25 AD risk loci) were computed in 1061 community-dwelling older adults. Participants were assessed on 11 cognitive tests and activities of daily living. Structural equation modeling was used to evaluate the association of the ANU-ADRI and GRS with: (1) general cognitive ability (g), (2) dementia-related variance in cognitive performance (δ), and (3) verbal ability (VA), episodic memory (EM), executive function (EF), and processing speed (PS). RESULTS: A worse ANU-ADRI score was associated with poorer performance in "g" [ß (SE)=-0.40 (0.02), P<0.001], δ [-0.40 (0.04), P<0.001], and each cognitive domain [VA=-0.29 (0.04), P<0.001; EM=-0.34 (0.03), P<0.001; EF=-0.38 (0.03), P<0.001; and PS=-0.40 (0.03), P<0.001]. A worse GRS was associated with poorer performance in δ [-0.08 (0.03), P=0.041] and EM [-0.10 (0.03), P=0.035]. CONCLUSIONS: The ANU-ADRI was broadly associated with worse cognitive performance, including general ability and dementia severity, validating its further use in early dementia risk assessment.

12.
J Sci Med Sport ; 22(7): 803-807, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30665754

RESUMO

OBJECTIVES: This study assessed the accuracy of two questionnaires for measuring the duration of physical activity (PA) by intensity compared to an objective measure in older adults. DESIGN: Cross-sectional observation METHODS: A total of 169 (female=43.8%) participants aged 73-78 years (mean: 75.1 y; SD: 1.3) wore a SenseWear™ Armband (SWA) for seven-days and reported the duration of PA by intensity with a Physical Activity Recall (PAR) questionnaire and the Active Australia Survey (AAS). In addition, the duration of moderate-to-vigorous-PA (MVPA) and overall active time, weighted for intensity (Total PA; MET: min/week) was assessed. Univariate general linear models were used to compare the questionnaire and SWA measures of PA while controlling for age, sex and education. RESULTS: The PAR was associated with SWA moderate intensity PA (b=0.19; 95% CI 0.03-0.35), MVPA (b=0.19; 95% CI 0.02-0.37) and Total PA (b=0.33; 95% CI 0.11-0.55). Although significant correlations were present, the models explained a small proportion of the variance in the SWA variables. The AAS was not associated with the SWA for any PA outcome. There was also significant under-reporting of PA duration for both questionnaires in comparison to the SWA. CONCLUSIONS: The PAR questionnaire may be suitable for determining the effect of greater levels of PA on health outcomes. However, neither questionnaire can be considered valid in determining the duration of PA divided by intensity. In addition, questionnaire and objectively measured PA are not equivalent and absolute measures of PA derived from questionnaires should be interpreted with caution.


Assuntos
Exercício/fisiologia , Autorrelato , Inquéritos e Questionários/estatística & dados numéricos , Acelerometria , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes
13.
Artigo em Inglês | MEDLINE | ID: mdl-30668830

RESUMO

OBJECTIVES: This study aimed to investigate the predictive value of cognitive/functional measures in combination with hippocampal volume on the probability of conversion from mild cognitive impairment (MCI) to Alzheimer's disease (AD). METHODS: The Rey Auditory Verbal Learning Test for immediate memory, Mini Mental State Examination, a functional assessment for independent daily activities and Alzheimer's Disease Assessment Scale were used as cognitive/functional measures and hippocampal volume as neuroimaging measure. Logistic regression and Cox proportional hazard analyses were used to explore the measures' predictive values for AD conversion and time to conversion. RESULTS: The probability of conversion from MCI to AD was associated with cognitive function, but this was moderated by hippocampal volume: higher at lower hippocampal volume and lower at higher hippocampal volume. General cognitive/functional measures were less predictive than immediate memory in predicting time to conversion to AD at small hippocampal volumes. CONCLUSION: Effectiveness of cognitive measures and subtle functional abnormality in predicting conversion from MCI to AD is dependent on hippocampal volume, thus combined evaluation should be considered. A combination of hippocampal volume and immediate memory appear to perform best in predicting time to conversion.

14.
Brain Imaging Behav ; 13(1): 65-74, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29243120

RESUMO

Strong evidence is available suggesting that effective reduction of exposure to demonstrated modifiable risk factors in mid-life or before could significantly decrease the incidence of Alzheimer's disease (AD) and delay its onset. A key ingredient to achieving this goal is the reliable identification of individuals at risk well before they develop clinical symptoms. The aim of this study was to provide further neuroimaging evidence of the effectiveness of a validated tool, the ANU Alzheimer's Disease Risk Index, for the assessment of future risk of cognitive decline. Participants were 461 (60-64 years, 48% female) community-living individuals free of dementia at baseline. Associations between risk estimates obtained with the ANU-ADRI, total and regional brain volumes including in the default mode network (DMN) measured at the same assessment and diagnosis of MCI/dementia over a 12-year follow-up were tested in a large sample of community-living individuals free of dementia at baseline. Higher risk estimates on the ANU-ADRI were associated with lower cortical gray matter and particularly in the DMN. Importantly, difference in participants with high and low risk scores explained 7-9% of the observed difference in gray matter volume. In this sample, every one additional risk point on the ANU-ADRI was associated with an 8% increased risk of developing MCI/dementia over a 12-year follow-up and this association was partly mediated by a sub-region of the DMN. Risk of cognitive decline assessed with a validated instrument is associated with gray matter volume, particularly in the DMN, a region known to be implicated in the pathological process of the disease.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico por imagem , Imagem por Ressonância Magnética , Medição de Risco , Doença de Alzheimer/epidemiologia , Doença de Alzheimer/patologia , Encéfalo/patologia , Disfunção Cognitiva/epidemiologia , Disfunção Cognitiva/patologia , Feminino , Seguimentos , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Medição de Risco/métodos , Fatores de Risco
15.
Hum Brain Mapp ; 40(6): 1697-1704, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30549129

RESUMO

The amygdala, an anatomical composite of several nuclei that have been grouped anatomically and functionally into three major subareas, has been reported to decrease in size with increasing age and to differ in size between male and female brains. However, findings are rather inconsistent across existing studies, possibly reflecting differences in the cohorts examined or the approaches chosen to define and measure the dimensions of the amygdala. Here, we investigated possible effects of age and sex on the amygdala as well as age-by-sex interactions in 100 healthy subjects (50 men/50 women) aged 18-69 years. For this purpose, we enhanced conventional imaging-based information with microscopically defined cytoarchitectonic probabilities to discriminate between different subareas. We observed significant negative correlations between age and all subareas of the amygdala indicating decreases over time, but with subarea-specific trajectories. In addition, we detected a significant quadratic association with age for the left superficial subarea suggesting an accelerating volume loss over time. Such regional information may serve as a frame of reference in future studies, not only for normative samples but also potentially for clinical populations known to present with an atypical atrophy of the amygdala. There were no sex differences and no interactions between sex and age, suggesting that the size of the amygdala is similar in male and female brains (at least when properly accounting for total intracranial volume) and that its age-related decline follows a similar trajectory in both sexes.

16.
Nutrients ; 11(1)2018 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-30586933

RESUMO

Manual review of the extensive literature covering nutrition-based lifestyle interventions to promote healthy cognitive ageing has proved educational, however, data-driven techniques can better account for the large size of the literature (tens of thousands of potentially relevant publications to date) and interdisciplinary nature, where relevant publications may be found. In this study, we present a new way to map the literature landscape, focusing on nutrition-based lifestyle interventions to promote healthy cognitive ageing. We applied a combination of citation network analysis and text mining to map out the existing literature on nutritional interventions and cognitive health. Results indicated five overarching clusters of publications, which could be further deconstructed into a total of 35 clusters. These could be broadly distinguished by the focus on lifespan stages (e.g., infancy versus older age), and specificity regarding nutrition (e.g., a narrow focus on iodine deficiency versus a broad focus on weight gain). Rather than concentrating into a single cluster, interventions were present throughout the majority of the research. We conclude that a data-driven map of the nutritional intervention literature can benefit the design of future interventions, by highlighting topics and themes that could be synthesized across currently disconnected clusters of publications.


Assuntos
Cognição , Mineração de Dados , Estado Nutricional , Projetos de Pesquisa , Humanos
17.
Front Aging Neurosci ; 10: 339, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30483112

RESUMO

This study aimed to determine whether sulcal morphology differs between middle age (MA) and older healthy individuals. Furthermore, we sought to determine whether age-related differences in sulcal characteristics were more strongly associated with differences in local or global cortical volumes. Participants (age 44-50, N = 403; age 64-70, N = 390) from the Personality and Total Health Through Life (PATH) study were included. Sulci were 17.3% wider, on average, in old age (OA) compared to MA participants, with the largest difference in the left superior frontal sulcus. Differences in sulcal width were generally higher in males than females. Differences in the width of the superior frontal and central sulci were significantly associated with differences in the volume of adjacent local gyri, while age-related differences in the width of lateral and superior temporal sulci were associated with differences in whole brain cortical volume. These findings suggest that sulcal characteristics provide unique information about changes in local and global brain structure in aging.

18.
Brain Topogr ; 31(6): 949-962, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29974288

RESUMO

It is important to have accurate estimates of normal age-related brain structure changes and to understand how the choice of measurement technique may bias those estimates. We compared longitudinal change in hippocampal volume, laterality and atrophy measured by manual tracing and FreeSurfer (version 5.3) in middle age (n = 244, 47.2[1.4] years) and older age (n = 199, 67.0[1.4] years) individuals over 8 years. The proportion of overlap (Dice coefficient) between the segmented hippocampi was calculated and we hypothesised that the proportion of overlap would be higher for older individuals as a consequence of higher atrophy. Hippocampal volumes produced by FreeSurfer were larger than manually traced volumes. Both methods produced a left less than right volume laterality difference. Over time this laterality difference increased for manual tracing and decreased for FreeSurfer leading to laterality differences in left and right estimated atrophy rates. The overlap proportion between methods was not significantly different for older individuals, but was greater for the right hippocampus. Estimated middle age annualised atrophy rates were - 0.39(1.0) left, 0.07(1.01) right, - 0.17(0.88) total for manual tracing and - 0.15(0.69) left, - 0.20(0.63) right, - 0.18(0.57) total for FreeSurfer. Older age atrophy rates were - 0.43(1.32) left, - 0.15(1.41) right, - 0.30 (1.23) total for manual tracing and - 0.34(0.79) left, - 0.68(0.78) right, - 0.51(0.65) total for FreeSurfer. FreeSurfer reliably segments the hippocampus producing atrophy rates that are comparable to manual tracing with some biases that need to be considered in study design. FreeSurfer is suited for use in large longitudinal studies where it is not cost effective to use manual tracing.


Assuntos
Envelhecimento/patologia , Hipocampo/diagnóstico por imagem , Adulto , Idoso , Atrofia , Feminino , Lateralidade Funcional , Hipocampo/patologia , Humanos , Estudos Longitudinais , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão
19.
Neurobiol Aging ; 69: 102-110, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29864716

RESUMO

The current challenge in clinical practice is to identify those with mild cognitive impairment (MCI), who are at greater risk of Alzheimer's disease (AD) conversion in the near future. The aim of this study was to assess a clinically practical new hippocampal index-hippocampal volume normalized by cerebellar volume (hippocampus to cerebellum volume ratio) used alone or in combination with scores on the Mini-Mental State Examination, as a predictor of conversion from MCI to AD. The predictive value of the HCCR was also contrasted to that of the hippocampal volume to intracranial volume ratio. The findings revealed that the performance of the combination of measures was significantly better than that of each measure used individually. The combination of Mini-Mental State Examination and hippocampal volume, normalized by the cerebellum or by intracranial volume, accurately discriminated individuals with MCI who progress to AD within 5 years from other MCI types (stable, reverters) and those with intact cognition (area under receiver operating curve of 0.88 and 0.89, respectively). Normalization by cerebellar volume was as accurate as normalization by intracranial volume with the advantage of being more practical, particularly for serial assessments.


Assuntos
Doença de Alzheimer/diagnóstico , Cerebelo/diagnóstico por imagem , Disfunção Cognitiva/diagnóstico , Hipocampo/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/patologia , Cerebelo/patologia , Disfunção Cognitiva/patologia , Progressão da Doença , Feminino , Hipocampo/patologia , Humanos , Imagem por Ressonância Magnética , Masculino , Testes de Estado Mental e Demência , Pessoa de Meia-Idade , Neuroimagem/métodos , Fatores de Risco , Sensibilidade e Especificidade
20.
Psychiatry Res Neuroimaging ; 278: 1-6, 2018 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-29935440

RESUMO

Previous studies have demonstrated associations between higher blood glucose and brain atrophy and functional deficits, however, little is known about the association between blood glucose, striatal volume and striatal function despite sensori-motor deficits being reported in diabetes. This study investigated the relationship between blood glucose levels, striatal volume and fine motor skills in a longitudinal cohort of cognitively healthy individuals living in the community with normal or impaired fasting glucose or type 2 diabetes. Participants were 271 cognitively healthy individuals (mean age 63 years at inclusion) with normal fasting glucose levels (<5.6 mmol/L) (n=173), impaired fasting glucose (5.6-6.9 mmol/L) (n=57), or with type 2 diabetes (≥7.0 mmol/L) (n=41). Fasting glucose, Purdue Pegboard scores as measurement of fine motor skills, and brain scans were collected at wave 1, 2 and 4, over a total follow-up of twelve years. Striatal volumes were measured using FreeSurfer after controlling for age, sex and intracranial volume. Results showed that type 2 diabetes was associated with smaller right putamen volume and lower Purdue Pegboard scores after controlling for age, sex and intracranial volume. These findings add to the evidence suggesting that higher blood glucose levels, especially type 2 diabetes, may impair brain structure and function.


Assuntos
Glicemia/fisiologia , Corpo Estriado/patologia , Diabetes Mellitus Tipo 2/patologia , Diabetes Mellitus Tipo 2/fisiopatologia , Destreza Motora/fisiologia , Corpo Estriado/fisiopatologia , Diabetes Mellitus Tipo 2/sangue , Jejum/sangue , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão/fisiologia
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