New data on harmful effects of trans-fatty acids

Various margarines containing trans-fatty acids were marketed as being healthier because of the absence of cholesterol, suggesting to use margarine instead of butter. Fifteen years ago, research documented the grave health risk of trans-fats (T-fat). US FDA in 2015 finalized its decision that T-fat is not safe and set a three-year time limit for complete removal of T-fat from all foods. The greatest danger from T-fat lies in its capacity to distort the cell membranes. The primary health risk identified for T-fat consumption is an elevated risk of coronary heart disease. T-fats have an adverse effect on the brain and nervous system. T-fat from the diet is incorporated into brain cell membranes and alter the ability of neurons to communicate. This can diminish mental performance. Relationship between T-fat intake and depression risk was observed. There is growing evidence for a possible role of T-fat in the development of Alzheimer´s disease and cognitive decline with age.

Increasing delirium skills at the front door: results from a repeated survey on delirium knowledge and attitudes

BACKGROUND

delirium is under-recognised in comparison to other common and serious acute disorders. A 2006 survey of UK junior doctors (not undertaking specialist training) identified poor knowledge of the diagnostic criteria and treatment of delirium. We hypothesised that increased prominence accorded to delirium in the form of national initiatives and guidelines may have had an impact on understanding among junior doctors.

OBJECTIVE

we repeated a multi-centre survey of knowledge of and attitudes to delirium in junior doctors (not undertaking specialist training) assessing unselected acute medical presentations (the 'medical take').

DESIGN

questionnaire-based survey in 48 acute hospitals in UK and Ireland.

METHODS

we used questionnaires designed to test understanding of delirium, including prevalence, knowledge of the DSM-IV diagnostic criteria, use of specific screening tools, association with adverse outcomes and pharmacological management.

RESULTS

one thousand two hundred and fifteen trainee physicians participated. Compared with the 2006 cohort, improvements were seen in 9 of 17 knowledge-based questions and overall score improved in the 2013 cohort. Nonetheless, significant deficits in knowledge, particularly for the diagnostic criteria for delirium, remained.

CONCLUSIONS

despite improvements in some aspects of delirium knowledge, the diagnostic criteria for delirium remain poorly understood. Challenges remain in ensuring adequate training for junior doctors in delirium.

Education as protector against dementia, but what exactly do we mean by education?

OBJECTIVES

even though a great number of research studies have shown that high education has protective effects against dementia, some studies did not observe such a significant effect. In that respect, the aim of our study was to investigate and compare various operationalisation approaches of education and how they impact dementia risk within one sample.

METHODS

data were derived from the Leipzig longitudinal study of the aged (LEILA75+). Individuals aged 75 and older underwent six cognitive assessments at an interval of 1.5 years and a final follow-up 15 years after the baseline assessment. We operationalised education according to different approaches used in previous studies and analysed the impact on dementia incidence via multivariate cox regression modelling.

RESULTS

the results showed that whether education is identified as significant protector against dementia strongly depends on the operationalisation of education. Whereas the pure number of years of education showed statistically significant protective effects on dementia risk, other more complex categorical classification approaches did not. Moreover, completing >10 years of education or a tertiary level seems to be an important threshold to significantly reduce dementia risk.

CONCLUSION

findings suggest a protective effect of more years of education on a lower dementia risk with a particular critical threshold of completing >10 years of education. Further, the findings highlight that, when examining risks and protective factors of dementia, a careful consideration of the underlying definitions and operationalisation approaches is required.

Age-dependent cognitive and affective differences in Alzheimer's and Parkinson's diseases in relation to MRI findings

OBJECTIVE

To compare age-dependent changes in cognitive and affective functions related to white matter changes between patients with Alzheimer's disease (AD) and Parkinson's disease (PD).

METHODS

We retrospectively compared age-dependent cognitive and affective functions in 216 AD patients, 153 PD patients, and 103 healthy controls with cerebral white matter lesions (WMLs), periventricular hyperintensity (PVH), deep white matter hyperintensity (DWMH), micro-bleeds (MBs), and lacunar infarcts (LIs).

RESULTS

The average mini-mental state examination (MMSE) scores were 19.6±6.1 and 26.8±3.6 in AD and PD patients, respectively. Significant decreases were found in the MMSE score, Hasegawa's dementia scale-revised (HDS-R) score, frontal assessment battery score, and Abe's BPSD score (ABS) among the age-dependent AD subgroups and in the MMSE, HDS-R, Montreal cognitive assessment, geriatric depression scale, and ABS scores among the age-dependent PD subgroups; they were worse in AD patients. White matter changes were observed in >88% and >72% of patients with AD and PD, respectively. An age-dependent direct comparison of AD and PD showed significant differences in the PVH and DWMH grades, and numbers of MBs and LIs.

CONCLUSION

WML-related cognitive and affective functions worsen with age in AD and PD patients; however, the abnormalities were more frequent and stronger in AD patients.

Bi-directional interaction between hypoglycaemia and cognitive impairment in elderly patients treated with glucose-lowering agents: a systematic review and meta-analysis

AIMS

To examine the bi-directional relationship, whereby hypoglycaemia is a risk factor for dementia, and where dementia increases risk of hypoglycaemia in older patients with diabetes mellitus treated with glucose-lowering agents.

METHODS

We searched MEDLINE and EMBASE over a 10-year span from 2005 to 2015 (with automated PubMed updates to August 2015) for observational studies of the association between hypoglycaemia and cognitive impairment or dementia in participants aged >55 years. Assessment of study validity was based on ascertainment of hypoglycaemia, dementia and risk of confounding. We conducted random effects inverse variance meta-analyses, and assessed heterogeneity using the I(2) statistic.

RESULTS

We screened 1177 citations, and selected 12 studies, of which nine were suitable for meta-analysis. There were a total of 1,439,818 participants, with a mean age of 75 years. Meta-analysis of five studies showed a significantly increased risk of dementia in patients who had hypoglycaemic episodes: pooled odds ratio 1.68 [95% confidence interval (CI) 1.45, 1.95]. We also found a significantly increased risk of hypoglycaemia in patients with dementia: pooled odds ratio from five studies 1.61 (95% CI 1.25, 2.06). Limitations of the study were heterogeneity in the meta-analysis, and uncertain ascertainment of dementia and hypoglycaemic outcomes and temporal relationships. Publication bias may have favoured the reporting of more significant findings.

CONCLUSIONS

Our meta-analysis shows a bi-directional relationship between cognitive impairment and hypoglycaemia in older patients. Glucose-lowering therapy should be carefully tailored and monitored in older patients who are susceptible to cognitive decline.

Where frailty meets diabetes

Diabetes is a chronic illness that has an effect on multiple organ systems. Frailty is a state of increased vulnerability to stressors and a limited capacity to maintain homeostasis. It is a multidimensional concept and a dynamic condition that can improve or worsen over time. Frailty is either physical or psychological or a combination of these two components. Sarcopenia, which is the age-related loss of skeletal muscle mass and strength, is the main attributor to the physical form of frailty. Although the pathophysiology of diabetes is commonly focused on impaired insulin secretion, overload of gluconeogenesis and insulin resistance, newer insights broaden this etiologic horizon. Immunologic factors that create a chronic state of low-grade inflammation--'inflammaging'--have an influence on both the ageing process and diabetes. Persons with diabetes mellitus already tend to have an accelerated ageing process that places them at greater risk for developing frailty at an earlier age. The development of frailty--and sarcopenia--is multifactorial and includes nutritional, physical and hormonal elements; these elements are interlinked with those of diabetes. A lower muscle mass will lead to poorer glycaemic control through lower muscle glucose uptake. This leads to higher insulin secretion and insulin resistance, which is the stepping stone for diabetes itself.

Cognitive Ageing in Great Britain in the New Century: Cohort Differences in Episodic Memory

BACKGROUND

Dementias in high income countries are set to be the third major burden of disease even as older people are increasingly required to think for themselves how to provide for their lives in retirement. Meanwhile the period of older age continues to extend with increase in life expectancy. This challenge demands an understanding of how cognition changes over an extended period in later life. But studying cognitive ageing in the population faces a difficulty from the fact that older respondents are liable to leave (attrite) before study completion. This study tested three hypotheses: trajectories of cognitive ageing in Britain show an improvement beyond the age of 50; and they are lifted by secular improvement in cognition across cohorts; lastly they are susceptible to distortion due to attrition.

METHODS AND FINDINGS

Using the English Longitudinal Study of Ageing, this paper studied trajectories of episodic memory of Britons aged 50-89 from 2002 to 2013 (N = 5931). Using joint models the analysis found that levels of episodic memory follow a curvilinear shape, not a steady decline, in later life. The findings also revealed secular improvement in cognitive ageing such that as a cohort is being replaced episodic memory levels in the population improve. The analysis lastly demonstrated that failure to simultaneously model attrition can produce distorted pictures of cognitive ageing.

CONCLUSION

Old age in this century is not necessarily a period dominated by cognitive decline. In identifying behavioural factors associated with better cognitive ageing, such as social connections of traditional and online kinds, the paper raises possibilities of mustering an adequate response to the cognition challenge.

Adult Lifespan Cognitive Variability in the Cross-Sectional Cam-CAN Cohort

This study examines variability across the age span in cognitive performance in a cross-sectional, population-based, adult lifespan cohort from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) study (n = 2680). A key question we highlight is whether using measures that are designed to detect age-related cognitive pathology may not be sensitive to, or reflective of, individual variability among younger adults. We present three issues that contribute to the debate for and against age-related increases in variability. Firstly, the need to formally define measures of central tendency and measures of variability. Secondly, in addition to the commonly addressed location-confounding (adjusting for covariates) there may exist changes in measures of variability due to confounder sub-groups. Finally, that increases in spread may be a result of floor or ceiling effects; where the measure is not sensitive enough at all ages. From the Cam-CAN study, a large population-based dataset, we demonstrate the existence of variability-confounding for the immediate episodic memory task; and show that increasing variance with age in our general cognitive measures is driven by a ceiling effect in younger age groups.

Understanding How Exercise Promotes Cognitive Integrity in the Aging Brain

Alterations in the structure and organization of the aging central nervous system (CNS), and associated functional deficits, result in cognitive decline and increase susceptibility to neurodegeneration. Age-related changes to the neurovascular unit (NVU), and their consequences for cerebrovascular function, are implicated as driving cognitive impairment during aging as well as in neurodegenerative disease. The molecular events underlying these effects are incompletely characterized. Similarly, the mechanisms underlying effects of factors that reduce the impact of aging on the brain, such as physical exercise, are also opaque. A study in this issue of PLOS Biology links the NVU to cognitive decline in the aging brain and suggests a potential underlying molecular mechanism. Notably, the study further links the protective effects of chronic exercise on cognition to neurovascular integrity during aging.

Individually modifiable risk factors to ameliorate cognitive aging: a systematic review and meta-analysis

A number of health and lifestyle factors are thought to contribute to cognitive decline associated with age but cannot be easily modified by the individual patient. We identified 12 individually modifiable interventions that can be implemented during midlife or later with the potential to ameliorate cognitive aging. For ten of these, we used PubMed databases for a systematic review of long-duration (at least 6 months), randomized, controlled trials in midlife and older adults without dementia or mild cognitive impairment with objective measures of neuropsychological performance. Using network meta-analysis, we performed a quantitative synthesis for global cognition (primary outcome) and episodic memory (secondary outcome). Of 1038 publications identified by our search strategy, 24 eligible trials were included in the network meta-analysis. Results suggested that the Mediterranean diet supplemented by olive oil and tai chi exercise may improve global cognition, and the Mediterranean diet plus olive oil and soy isoflavone supplements may improve memory. Effect sizes were no more than small (standardized mean differences 0.11-0.22). Cognitive training may have cognitive benefit as well. Most individually modifiable risk factors have not yet been adequately studied. We conclude that some interventions that can be self-initiated by healthy midlife and older adults may ameliorate cognitive aging.

Neuroprogression and Cognitive Functioning in Bipolar Disorder: A Systematic Review

Bipolar disorder (BD) has been associated with impairments in a range of cognitive domains including attention, verbal learning, and mental flexibility. These deficits are increased during the acute phases of the illness and worsen over the course of BD. This review will examine the literature in relation to potential mechanisms associated with cognitive decline in BD. Scopus (all databases), Pubmed, and Ovid Medline were systematically searched with no language or year restrictions, up to January 2015, for human studies that collected cross-sectional and longitudinal cognitive data in adults with BD and matched healthy controls (HC). Selected search terms were "bipolar," "cognitive," "aging," "illness duration," "onset," and "progression." Thirty-nine studies satisfied the criteria for consideration. There is evidence that cognitive function in BD is negatively associated with features of illness progression such as number of mood episodes, illness duration, and hospitalizations. Aging does not appear to affect cognitive functioning to a greater extent than in HC. Furthermore, the small number of longitudinal studies in this field does not allow to reaching firm conclusion in terms of which sub-populations would be more prone to cognitive decline in BD. The decline in cognitive abilities over the course of the BD seems to be associated with the number of episodes and number of hospitalizations. No meaningful interaction of age and bipolar disorder has been found in terms of cognitive decline. Future large-scale longitudinal studies are necessary to confirm these findings and assist in the development of preventive interventions in vulnerable individuals.

Health Span-Extending Activity of Human Amniotic Membrane- and Adipose Tissue-Derived Stem Cells in F344 Rats

Aging brings about the progressive decline in cognitive function and physical activity, along with losses of stem cell population and function. Although transplantation of muscle-derived stem/progenitor cells extended the health span and life span of progeria mice, such effects in normal animals were not confirmed. Human amniotic membrane-derived mesenchymal stem cells (AMMSCs) or adipose tissue-derived mesenchymal stem cells (ADMSCs) (1×10(6) cells per rat) were intravenously transplanted to 10-month-old male F344 rats once a month throughout their lives. Transplantation of AMMSCs and ADMSCs improved cognitive and physical functions of naturally aging rats, extending life span by 23.4% and 31.3%, respectively. The stem cell therapy increased the concentration of acetylcholine and recovered neurotrophic factors in the brain and muscles, leading to restoration of microtubule-associated protein 2, cholinergic and dopaminergic nervous systems, microvessels, muscle mass, and antioxidative capacity. The results indicate that repeated transplantation of AMMSCs and ADMSCs elongate both health span and life span, which could be a starting point for antiaging or rejuvenation effects of allogeneic or autologous stem cells with minimum immune rejection.

SIGNIFICANCE

This study demonstrates that repeated treatment with stem cells in normal animals has antiaging potential, extending health span and life span. Because antiaging and prolonged life span are issues currently of interest, these results are significant for readers and investigators.

Long-term consequences of estrogens administered in midlife on female cognitive aging

This article is part of a Special Issue "Estradiol and cognition". Many of the biochemical, structural, and functional changes that occur as the female brain ages are influenced by changes in levels of estrogens. Administration of estrogens begun during a critical window near menopause is hypothesized to prevent or delay age-associated cognitive decline. However, due to potential health risks women often limit use of estrogen therapy to a few years to treat menopausal symptoms. The long-term consequences for the brain of short-term use of estrogens are unknown. Interestingly, there are preliminary data to suggest that short-term use of estrogens during the menopausal transition may afford long-term cognitive benefits to women as they age. Thus, there is the intriguing possibility that short-term estrogen therapy may provide lasting benefits to the brain and cognition. The focus of the current review is an examination of the long-term impact for cognition of midlife use of estrogens. We review data from our lab and others indicating that the ability of midlife estrogens to impact estrogen receptors in the hippocampus may contribute to its ability to exert lasting impacts on cognition in aging females.

Brain Amyloid Deposition and Longitudinal Cognitive Decline in Nondemented Older Subjects: Results from a Multi-Ethnic Population

Objective

We aimed to whether the abnormally high amyloid-β (Aβ) level in the brain among apparently healthy elders is related with subtle cognitive deficits and/or accelerated cognitive decline.

Methods

A total of 116 dementia-free participants (mean age 84.5 years) of the Washington Heights Inwood Columbia Aging Project completed 18F-Florbetaben PET imaging. Positive or negative cerebral Aβ deposition was assessed visually. Quantitative cerebral Aβ burden was calculated as the standardized uptake value ratio in pre-established regions of interest using cerebellar cortex as the reference region. Cognition was determined using a neuropsychological battery and selected tests scores were combined into four composite scores (memory, language, executive/speed, and visuospatial) using exploratory factor analysis. We examined the relationship between cerebral Aβ level and longitudinal cognition change up to 20 years before the PET scan using latent growth curve models, controlling for age, education, ethnicity, and Apolipoprotein E (APOE) genotype.

Results

Positive reading of Aβ was found in 41 of 116 (35%) individuals. Cognitive scores at scan time was not related with Aβ. All cognitive scores declined over time. Aβ positive reading (B = -0.034, p = 0.02) and higher Aβ burden in temporal region (B = -0.080, p = 0.02) were associated with faster decline in executive/speed. Stratified analyses showed that higher Aβ deposition was associated with faster longitudinal declines in mean cognition, language, and executive/speed in African-Americans or in APOE ε4 carriers, and with faster memory decline in APOE ε4 carriers. The associations remained significant after excluding mild cognitive impairment participants.

Conclusions

High Aβ deposition in healthy elders was associated with decline in executive/speed in the decade before neuroimaging, and the association was observed primarily in African-Americans and APOE ε4 carriers. Our results suggest that measuring cerebral Aβ may give us important insights into the cognitive profile in the years prior to the scan in cognitively normal elders.

Associations between Verbal Learning Slope and Neuroimaging Markers across the Cognitive Aging Spectrum

A symptom of mild cognitive impairment (MCI) and Alzheimer's disease (AD) is a flat learning profile. Learning slope calculation methods vary, and the optimal method for capturing neuroanatomical changes associated with MCI and early AD pathology is unclear. This study cross-sectionally compared four different learning slope measures from the Rey Auditory Verbal Learning Test (simple slope, regression-based slope, two-slope method, peak slope) to structural neuroimaging markers of early AD neurodegeneration (hippocampal volume, cortical thickness in parahippocampal gyrus, precuneus, and lateral prefrontal cortex) across the cognitive aging spectrum [normal control (NC); (n=198; age=76±5), MCI (n=370; age=75±7), and AD (n=171; age=76±7)] in ADNI. Within diagnostic group, general linear models related slope methods individually to neuroimaging variables, adjusting for age, sex, education, and APOE4 status. Among MCI, better learning performance on simple slope, regression-based slope, and late slope (Trial 2-5) from the two-slope method related to larger parahippocampal thickness (all p-values<.01) and hippocampal volume (p<.01). Better regression-based slope (p<.01) and late slope (p<.01) were related to larger ventrolateral prefrontal cortex in MCI. No significant associations emerged between any slope and neuroimaging variables for NC (p-values ≥.05) or AD (p-values ≥.02). Better learning performances related to larger medial temporal lobe (i.e., hippocampal volume, parahippocampal gyrus thickness) and ventrolateral prefrontal cortex in MCI only. Regression-based and late slope were most highly correlated with neuroimaging markers and explained more variance above and beyond other common memory indices, such as total learning. Simple slope may offer an acceptable alternative given its ease of calculation.

The role of cognitive function in the relationship between age and health literacy: a cross-sectional analysis of older adults in Chicago, USA

OBJECTIVES

To investigate how 3 measures of health literacy correlate with age and the explanatory roles of fluid and crystallised cognitive abilities in these relationships among older adults.

DESIGN

Cross-sectional baseline analysis of the 'LitCog' cohort study.

SETTING

1 academic internal medicine clinic and 5 federally qualified health centres in Chicago, USA.

PARTICIPANTS

English-speaking adults (n=828) aged 55-74 years, recruited from August 2008 through October 2011.

OUTCOME MEASURES

Health literacy was measured by the Test of Functional Health Literacy in Adults (TOFHLA) and the Newest Vital Sign (NVS), both of which assess reading comprehension and numeracy in health contexts, and by the Rapid Estimate of Adult Literacy in Medicine (REALM), which assesses medical vocabulary. Fluid cognitive ability was assessed through the cognitive domains of processing speed, inductive reasoning, and working, prospective and long-term memories, and crystallised cognitive ability through the verbal ability domain.

RESULTS

TOFHLA and NVS scores were lower at ages 70-74 years compared with all other age groups (p<0.05 for both tests). The inverse association between age and TOFHLA score was attenuated from β=-0.39 (95% CI -0.55 to -0.22) to β=-0.06 (95% CI -0.20 to 0.08) for ages 70-74 vs 55-59 years when fluid cognitive ability was added to the model (85% attenuation). Similar results were seen with NVS scores (68% attenuation). REALM scores did not differ by age group (p=0.971). Crystallised cognitive ability was stable across age groups, and did not influence the relationships between age and TOFHLA or NVS performance.

CONCLUSIONS

Health literacy skills show differential patterns of age-related change, which may be explained by cognitive ageing. Researchers should select health literacy tests appropriate for their purposes when assessing the health literacy of older adults. Clinicians should be aware of this issue to ensure that health self-management tasks for older patients have appropriate cognitive and literacy demands.

Ten-year longitudinal trajectories of older adults' basic and everyday cognitive abilities

OBJECTIVE

To examine the longitudinal trajectories of everyday cognition and longitudinal associations with basic (i.e., laboratory and experimentally measured) cognitive abilities, including verbal memory, inductive reasoning, visual processing speed, and vocabulary.

METHOD

Participants were healthy older adults drawn from the no-treatment control group (N = 698) of the Advanced Cognitive Training for the Independent and Vital Elderly (Willis et al., 2006) randomized trial and were assessed at baseline and 1, 2, 3, 5, and 10 years later. Analyses were conducted using latent growth models.

RESULTS

Modeling revealed an overall inverted-U shape (quadratic) trajectory across cognitive domains. Among basic cognitive predictors, level and slope in reasoning demonstrated the closest association to level and slope of everyday cognition, and accounted for most of the individual differences in linear gain in everyday cognition.

CONCLUSION

Everyday cognition is not buffered against decline, and is most closely related to inductive reasoning in healthy older adults. To establish the clinical utility of everyday cognitive measures, future research should examine these associations in samples with more cognitive impairment.

The dynamic relationship between physical function and cognition in longitudinal aging cohorts

On average, older people remember less and walk more slowly than do younger persons. Some researchers argue that this is due in part to a common biologic process underlying age-related declines in both physical and cognitive functioning. Only recently have longitudinal data become available for analyzing this claim. We conducted a systematic review of English-language research published between 2000 and 2011 to evaluate the relations between rates of change in physical and cognitive functioning in older cohorts. Physical functioning was assessed using objective measures: walking speed, grip strength, chair rise time, flamingo stand time, and summary measures of physical functioning. Cognition was measured using mental state examinations, fluid cognition, and diagnosis of impairment. Results depended on measurement type: Change in grip strength was more strongly correlated with mental state, while change in walking speed was more strongly correlated with change in fluid cognition. Examining physical and cognitive functioning can help clinicians and researchers to better identify individuals and groups that are aging differently and at different rates. In future research, investigators should consider the importance of identifying different patterns and rates of decline, examine relations between more diverse types of measures, and analyze the order in which age-related declines occur.