Relationship between education and dementia: an updated systematic review

Determinants of cognitive performance and decline in 20 diverse ethno-regional groups: A COSMIC collaboration cohort study

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.

Childhood Lead Exposure and Adult Neurodegenerative Disease

Millions of Americans now entering midlife and old age were exposed to high levels of lead, a neurotoxin, as children. Evidence from animal-model and human observational studies suggest that childhood lead exposure may raise the risk of adult neurodegenerative disease, particularly dementia, through a variety of possible mechanisms including epigenetic modification, delayed cardiovascular and kidney disease, direct degenerative CNS injury from lead remobilized from bone, and lowered neural and cognitive reserve. Within the next ten years, the generation of children with the highest historical lead exposures, those born in the 1960s, 1970s, and 1980s, will begin to enter the age at which dementia symptoms tend to emerge. Many will also enter the age in which lead stored in the skeleton may be remobilized at greater rates, particularly for women entering menopause and men and women experiencing osteoporosis. Should childhood lead exposure prove pro-degenerative, the next twenty years will provide the last opportunities for possible early intervention to forestall greater degenerative disease burden across the aging lead-exposed population. More evidence is needed now to characterize the nature and magnitude of the degenerative risks facing adults exposed to lead as children and to identify interventions to limit long-term harm.

Increased Prevalence of Obesity/Type 2 Diabetes and Lower Levels of Lithium in Rural Texas Counties May Explain Greater Alzheimer's Disease Risk

BACKGROUND/OBJECTIVE

To compare Alzheimer's disease (AD) mortality rates and coinciding risk factors in rural and urban Texas populations.

METHODS

155 Texas counties were divided into 73 rural and 82 urban areas using the U.S. Census Bureau definition of rurality. Changes in age-adjusted AD mortality across these counties were calculated using a 7-year aggregation model from 2000-2006 and 2009-2015. Data pertaining to gender, race, education, obesity, diabetes, physical inactivity, and lithium concentrations in tap water were also collected from readily available databases.

RESULTS

Change in age-adjusted AD mortality was higher in rural counties (9.5±1.4) versus urban (5.9±1.1) over the time period examined. Similarly, obesity (30.2±0.2% ), diabetes (11.0±0.1% ), and physical inactivity (29.4±0.2% ) levels were significantly higher in rural populations compared to urban (29.1±0.2%, 9.7±0.1%, and 26.7±0.3, respectively). In contrast, the percent of population with some college education (40.1±0.7% ) was lower compared to urban (29.4±0.2% and 44.4±0.9%, respectively). Lithium concentrations in tap water was significantly lower in rural counties compared to urban (63.3±8.2 and 33.4±4.7μg/L, respectively). No significant differences were observed among females and however, we did find significant differences in the percent of African American and Hispanics. Correlational analysis uncovered a negative association between education status and AD mortality over time (r = -0.17). Further analysis controlling for physical inactivity, education, and trace lithium concentrations results in a loss of statistical significance.

CONCLUSIONS

AD mortality rates are higher in rural counties when compared to urban counties, and this may be linked to greater physical inactivity, obesity, and diabetes, as well as lower trace lithium levels in tap water.

Verbal fluency and risk of dementia

OBJECTIVE

Verbal fluency is a common neuropsychological test that is impaired in dementia. We test whether verbal fluency is a prospective risk factor for incident dementia, cognitive impairment not dementia (CIND), and conversion from CIND to dementia.

METHODS

Participants (N = 18 189) from the Health and Retirement Study were administered a standard test of verbal fluency and were assessed for cognitive status every 2 years between baseline and 6 years' follow-up.

RESULTS

Every standard deviation increase in verbal fluency was associated with an approximately 60% reduced risk of incident dementia, an approximately 25% reduced risk of incident CIND, and an approximately 25% reduced risk of conversion from CIND to dementia. These associations were independent of age, gender, education, race, ethnicity, and APOE risk status. The associations were slightly weaker (but still significant) for African Americans and individuals with lower education. There was no interaction between verbal fluency and APOE risk status.

CONCLUSION

Verbal fluency is an easily administered task that is predictive of incident cognitive impairment.

Lifespan Intellectual Factors, Genetic Susceptibility, and Cognitive Phenotypes in Aging: Implications for Interventions

Along with rapid global population aging, the age-related cognitive disorders such as mild cognitive impairment (MCI) and dementia have posed a serious threat to public health, health care system, and sustainable economic and societal development of all countries. In this narrative review, we seek to summarize the major epidemiological studies from the life-course perspective that investigate the influence of genetic susceptibility [e.g., apolipoprotein (APOE) ε4 allele] and intellectual or psychosocial factors (e.g., educational attainments and leisure activities) as well as their interactions on cognitive phenotypes in aging. Numerous population-based studies have suggested that early-life educational attainments and socioeconomic status, midlife work complexity and social engagements, late-life leisure activities (social, physical, and mentally-stimulating activities), certain personality traits (e.g., high neuroticism and low conscientiousness), and depression significantly affect late-life cognitive phenotypes. Furthermore, certain intellectual or psychosocial factors (e.g., leisure activities and depression) may interact with genetic susceptibility (e.g., APOE ε4 allele) to affect the phenotypes of cognitive aging such that risk or beneficial effects of these factors on cognitive function may vary by carrying the susceptibility genes. Current evidence from the randomized controlled trials that support the cognitive benefits of cognitive training among cognitive healthy older adults remains limited. The cognitive reserve hypothesis has been proposed to partly explain the beneficial effects of lifetime intellectual and psychosocial factors on late-life cognitive function. This implies that, from a life-course perspective, preventive intervention strategies targeting multiple modifiable intellectual and psychosocial factors could interfere with clinical expression of cognitive disorders in old age and delay the onset of dementia syndrome, and thus, may help achieve healthy brain aging.

Analysis of combined incident and prevalent cohort data under a proportional mean residual life model

The Nun Study, a longitudinal study to examine risk factors for the progression of dementia, consists of subjects who were already diagnosed with dementia (ie, prevalent cohort) and those who do not have dementia (ie, incident cohort) at study enrollment. When assessing the risk factors' effects on the survival time from dementia diagnosis until death, utilizing data from both cohorts supports more efficient statistical inference because the two cohorts provide valuable complementary information. A major challenge in analyzing the combined cohort data is that the prevalent cases are not representative of the target population. Moreover, the dates of dementia diagnosis are not ascertained for the prevalent cohort in the Nun Study. Hence, the survival time for the prevalent cohort is only partially observed from study enrollment until death or censoring, with the time from dementia diagnosis to study enrollment missing. In this paper, we propose an efficient estimation method that uses both incident and prevalent cohorts under the proportional mean residual life model. By assuming proportionality of the mean residual life time with covariates in the incident cohort, we can utilize the natural relationship between the mean residual life function and the hazard function of the survival time measured from enrollment until death for the prevalent cohort. We evaluate the efficiency gain from using the combined cohort data through simulations and demonstrate that the proposed method is valid and efficient.

Aging, lifestyle and dementia

Aging is the greatest risk factor for most diseases including cancer, cardiovascular disorders, and neurodegenerative disease. There is emerging evidence that interventions that improve metabolic health with aging may also be effective for brain health. The most robust interventions are non-pharmacological and include limiting calorie or protein intake, increasing aerobic exercise, or environmental enrichment. In humans, dietary patterns including the Mediterranean, Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) and Okinawan diets are associated with improved age-related health and may reduce neurodegenerative disease including dementia. Rapamycin, metformin and resveratrol act on nutrient sensing pathways that improve cardiometabolic health and decrease the risk for age-associated disease. There is some evidence that they may reduce the risk for dementia in rodents. There is a growing recognition that improving metabolic function may be an effective way to optimize brain health during aging.

Effects of sustained cognitive activity on white matter microstructure and cognitive outcomes in healthy middle-aged adults: A systematic review

Adults who remain cognitively active may be protected from age-associated changes in white matter (WM) and cognitive decline. To determine if cognitive activity is a precursor for WM plasticity, the available literature was systematically searched for Region of Interest (ROI) and whole-brain studies assessing the efficacy of cognitive training (CT) on WM microstructure using Diffusion Tensor Imaging (DTI) in healthy adults (> 40 years). Seven studies were identified and included in this review. Results suggest there are beneficial effects to WM microstructure after CT in frontal and medial brain regions, with some studies showing improved performance in cognitive outcomes. Benefits of CT were shown to be protective against age-related WM microstructure decline by either maintaining or improving WM after training. These results have implications for determining the capacity for training-dependent WM plasticity in older adults and whether CT can be utilised to prevent age-associated cognitive decline. Additional studies with standardised training and imaging protocols are needed to confirm these outcomes.

General and domain-specific cognitive reserve, mild cognitive impairment, and dementia risk in older women

INTRODUCTION

In a geographically diverse sample of women, we asked whether cognitive reserve (CR) is best viewed as a general or cognitive domain-specific construct and whether some cognitive reserve domains but not others exert protective effects on risk of developing mild cognitive impairment (MCI) or dementia.

METHODS

Estimates of general and domain-specific CR were derived via variance decomposition in 972 cognitively intact women from the Women's Health Initiative Study of Cognitive Aging and Women's Health Memory Study Magnetic Resonance Imaging. Women were then followed up for 13 years.

RESULTS

General CR was the strongest predictor of reduced risk for both MCI and dementia, compared to domain-specific CR measures. Verbal memory, figural memory, and spatial CR were independently protective of MCI, but only verbal memory was independently associated with reduced risk for dementia.

DISCUSSION

Cognitive reserve is a heterogenous construct with valid quantitative measures identifiable across different neuropsychological processes associated with MCI and dementia.

Identifying risk factors for cognitive issues in multiple sclerosis

INTRODUCTION

Cognitive impairment (CI) in Multiple Sclerosis (MS) has progressively regained clinical and research interest and is currently recognized as a debilitating and burdensome problem for these patients. Studying risk and protecting factors that may influence the development and course of CI is currently an area of increasing interest, due to the potential for preventive strategies. Areas covered: In this narrative review the authors briefly addressed the physiopathologic basis, assessment and management of CI in MS and then focused on identifying modifiable and not modifiable risk factors for CI in MS, providing an overview of the current knowledge in the field and indicating avenues for future research. Expert opinion: Improving our understanding of potentially modifiable environmental and lifestyle risk factors or protective factors for CI is important in order to prompt preventive strategies and orient patient counselling and clinical management. To this aim, we need to enhance the current level of evidence linking lifestyle factors to cognition and evaluate some factors that were only preliminary addressed in research. Moreover, we need to explore the role of each factor into the subject cognitive outcome, next to the possible interactions between different environmental factors as well as between environmental and genetic factors.

A Systematic Review for Functional Neuroimaging Studies of Cognitive Reserve Across the Cognitive Aging Spectrum

Objective

Cognitive reserve has been proposed to explain the discrepancy between clinical symptoms and the effects of aging or Alzheimer's pathology. Functional magnetic resonance imaging (fMRI) may help elucidate how neural reserve and compensation delay cognitive decline and identify brain regions associated with cognitive reserve. This systematic review evaluated neural correlates of cognitive reserve via fMRI (resting-state and task-related) studies across the cognitive aging spectrum (i.e., normal cognition, mild cognitive impairment, and Alzheimer's disease).

Method

This review examined published articles up to March 2017. There were 13 cross-sectional observational studies that met the inclusion criteria, including relevance to cognitive reserve, subjects 60 years or older with normal cognition, mild cognitive impairment, and/or Alzheimer's disease, at least one quantitative measure of cognitive reserve, and fMRI as the imaging modality. Quality assessment of included studies was conducted using the Newcastle-Ottawa Scale adapted for cross-sectional studies.

Results

Across the cognitive aging spectrum, medial temporal regions and an anterior or posterior cingulate cortex-seeded default mode network were associated with neural reserve. Frontal regions and the dorsal attentional network were related to neural compensation. Compared to neural reserve, neural compensation was more common in mild cognitive impairment and Alzheimer's disease.

Conclusions

Neural reserve and compensation both support cognitive reserve, with compensation more common in later stages of the cognitive aging spectrum. Longitudinal and intervention studies are needed to investigate changes between neural reserve and compensation during the transition between clinical stages, and to explore the causal relationship between cognitive reserve and potential neural substrates.

Epidemiology of dementia: prevalence and incidence estimates using validated electronic health records from primary care

Purpose

Updated estimates of incidence and prevalence of dementia are crucial to ensure adequate public health policy. However, most of the epidemiological studies in the population in Spain were conducted before 2010. This study assessed the validity of dementia diagnoses recorded in electronic health records contained in a large primary-care database to determine if they could be used for research purposes. Then, to update the epidemiology of dementia in Catalonia (Spain), we estimated crude and standardized prevalence and incidence rates of dementia in Catalonia in 2016.

Methods

The System for the Development of Research in Primary Care (SIDIAP) database contains anonymized information for >80% of the Catalan population. Validity of dementia codes in SIDIAP was assessed in patients at least 40 years old by asking general practitioners for additional evidence to support the diagnosis. Crude and standardized incidence and prevalence (95% CI) in people aged ≥65 years were estimated assuming a Poisson distribution.

Results

The positive predictive value of dementia diagnoses recorded in SIDIAP was estimated as 91.0% (95% CI 87.5%–94.5%). Age-and sex-standardized incidence and prevalence of dementia were 8.6/1,000 person-years (95% CI 8.0–9.3) and 5.1% (95% CI 4.5%–5.7%), respectively.

Conclusion

SIDIAP contains valid dementia records. We observed incidence and prevalence estimations similar to recent face-to-face studies conducted in Spain and higher than studies using electronic health data from other European populations.

[Prevalence of dementia in the elderly in Latin America: A systematic review]

BACKGROUND AND OBJECTIVE

Dementia is a growing public health problem. It involves the impairment of several cognitive functions, generating mental and physical disability, and therefore greater functional dependence. There is limited epidemiological information which reveals an approximate prevalence in older adults from Latin America. The objective of this study was to determine the prevalence of dementia in the older adult population of Latin America, and its distribution according to geographic area and gender.

MATERIALS AND METHODS

A systematic review was carried out in databases: PubMed, Ovid, Lilacs, Cochrane, Scielo and Google Scholar, in order to identify studies that estimate the prevalence of dementia in urban and / or rural population over 65 years of age.

RESULTS

On February 2018, the literature search yielded 357 publications. The overall prevalence of dementia in the older adult population of Latin America was found to be 11%, prevailing more in female gender and urban people.

CONCLUSION

The prevalence of dementia in Latin America is higher than registered previously, and even than in other continents.

The Cretan Aging Cohort: Cohort Description and Burden of Dementia and Mild Cognitive Impairment

Our aim was to explore the burden of dementia in the Cretan Aging Cohort, comprised of 3140 persons aged ≥60 years (56.8% women, 5.8 ± 3.3 years formal education, 86.2% living in rural areas) who attended selected primary health-care facilities on the island of Crete, Greece. In the first study phase, a formal diagnosis of dementia had been reached in 4.0% of the participants. However, when selected 505 participants underwent thorough neuropsychiatric evaluation in the second phase of this study (344 with Mini-Mental State Examination [MMSE] <24 and 161 with MMSE ≥24), and results were extrapolated to the entire cohort, the prevalence of dementia and mild cognitive impairment was estimated at 10.8% (9.7%-11.9%) and 32.4% (30.8%-34.0%), respectively. Using both the field diagnostic data and the extrapolated data, the highest dementia prevalence (27.2%) was found in the 80- to 84-year-old group, who also showed the lowest educational level, apparently due to lack of schooling during World War II.

Increased Serum Acylated Ghrelin Levels in Patients with Mild Cognitive Impairment

Ghrelin is a stomach-derived circulating hormone. In addition to its function as an orexigenic stimulant, the role of ghrelin in the consolidation of learning and memory has been implicated in recent years. However, the status of circulating acylated ghrelin (AG, that is, the functional form of ghrelin) in the symptomatic predementia stage of Alzheimer's disease (AD) has rarely been investigated. In the current study, we examined the serum levels of acylated and total ghrelin in 22 patients with mild cognitive impairment (MCI) and 30 cognitively normal controls. We have found that patients with MCI had significantly increased serum AG levels, which were inversely associated with defected short- and long-term memory as well as language skills. Of note, the levels of total circulating ghrelin were similar between the two groups. Intriguingly, serum AG but not total ghrelin was associated with AD risk factors including the age, hypertension, and hyperlipidemia. Therefore, circulating AG may serve as a potential early systemic biomarker for AD-related cognitive impairments. Nevertheless, the simplest interpretation of the results is that the levels of circulating AG are associated with cognitive impairments in patients with MCI, thereby forming the groundwork for our future studies on the systemic mechanisms of AD pertaining to the ghrelin system.

Defining Cognitive Reserve and Implications for Cognitive Aging

PURPOSE OF REVIEW

The aim of this review is to summarize current conceptual models of cognitive reserve (CR) and related concepts and to discuss evidence for these concepts within the context of aging and Alzheimer's disease.

RECENT FINDINGS

Evidence to date supports the notion that higher levels of CR, as measured by proxy variables reflective of lifetime experiences, are associated with better cognitive performance, and with a reduced risk of incident mild cognitive impairment/dementia. However, the impact of CR on longitudinal cognitive trajectories is unclear and may be influenced by a number of factors. Although there is promising evidence that some proxy measures of CR may influence structural brain measures, more research is needed. The protective effects of CR may provide an important mechanism for preserving cognitive function and cognitive well-being with age, in part because it can be enhanced throughout the lifespan. However, more research on the mechanisms by which CR is protective is needed.

Modifiable Risk Factors Explain Socioeconomic Inequalities in Dementia Risk: Evidence from a Population-Based Prospective Cohort Study

BACKGROUND

Differences in dementia risk across the gradient of socioeconomic status (SES) exist, but their determinants are not well understood.

OBJECTIVE

This study investigates whether health conditions and lifestyle-related risk factors explain the SES inequalities in dementia risk.

METHODS

6,346 participants from the English Longitudinal Study of Ageing were followed up from 2008/2009 until 2014/2015. We used Cox regression adjusted for age, gender, wealth/education, and clustering at the household level to examine the association between SES markers (wealth, education) and time to dementia in a structural equation model including potential mediation or effect modification by a weighted compound score of twelve modifiable risk and protective factors for dementia ('LIfestyle for BRAin health' (LIBRA) score).

RESULTS

During a median follow-up of 6 years, 192 individuals (3.0%) developed dementia. LIBRA scores decreased with increasing wealth and higher educational level. A one-point increase in the LIBRA score was associated with a 13% increase in dementia risk (hazard ratio (HR) = 1.13, 95% confidence interval 1.07-1.19). Higher wealth was associated with a decreased dementia risk (HR = 0.58, 0.39-0.85). Mediation analysis showed that 52% of the risk difference between the highest and lowest wealth tertile was mediated by differences in LIBRA (indirect effect: HR = 0.75, 0.66-0.85). Education was not directly associated with dementia (HR = 1.05, 0.69-1.59), but was a distal risk factor for dementia by explaining differences in wealth and LIBRA scores (indirect effect high education: HR = 0.92, 0.88-0.95).

CONCLUSION

Socioeconomic differences in dementia risk can be partly explained by differences in modifiable health conditions and lifestyle factors.

An investigation into the prevalence of cognitive impairment and the performance of older adults in Guilan province

Introduction: The escalating rate of old people with a functional impairment in Iran and the weakness of the family support due to the diminishing of family size have increased the demand for long-term care for the elderly with cognitive impairment (CI).

Objective: The purpose of this research is to explore the frequency of cognitive impairment in the elderly and its association with their daily functional impairment and disability.

Method: This is a cross-sectional and descriptive-analytic study conducted in 2016-2017. The study sample consisted of 393 elderly people who were 60 years old or older who live in of Guilan different counties. Samples were selected by using multi-stage cluster sampling. Subsequently, data were analyzed by using the Chi-square test and correlation and regression analysis conducted in SPSS 22.

Results: It was observed that 4.3, 28.6, and 37% of the subjects suffered from severe, moderate, and mild cognitive impairment, respectively. Cognitive impairment had a significant relationship with daily functioning and activities requiring special tools. Moreover, cognitive impairment in women, people with low education, and those over 70 years old was more common, and the difference between them was significant (p <0.001). Also, disability was significantly greater in the elderly with cognitive impairment.

Conclusion: Many old people need to be cared for after the appearance of cognitive impairment. Therefore, appropriate screening of cognitive impairments is conducive to early diagnosis and prevention of executive functioning problems.

Lifestyle Factors Are Important Contributors to Subjective Memory Complaints among Patients without Objective Memory Impairment or Positive Neurochemical Biomarkers for Alzheimer's Disease

Background/Aims

Many patients presenting to a memory disorders clinic for subjective memory complaints do not show objective evidence of decline on neuropsychological data, have nonpathological biomarkers for Alzheimer's disease, and do not develop a neurodegenerative disorder. Lifestyle variables, including subjective sleep problems and stress, are factors known to affect cognition. Little is known about how these factors contribute to patients' subjective sense of memory decline. Understanding how lifestyle factors are associated with the subjective sense of failing memory that causes patients to seek a formal evaluation is important both for diagnostic workup purposes and for finding appropriate interventions and treatment for these persons, who are not likely in the early stages of a neurodegenerative disease. The current study investigated specific lifestyle variables, such as sleep and stress, to characterize those patients that are unlikely to deteriorate cognitively.

Methods

Two hundred nine patients (mean age 58 years) from a university hospital memory disorders clinic were included.

Results

Sleep problems and having much to do distinguished those with subjective, but not objective, memory complaints and non-pathological biomarkers for Alzheimer's disease.

Conclusions

Lifestyle factors including sleep and stress are useful in characterizing subjective memory complaints from objective problems. Inclusion of these variables could potentially improve health care utilization efficiency and guide interventions.

Migration of adult children and mental health of older parents 'left behind': An integrative review

Background

Although a number of studies have examined the effect of the out-migration of children on the mental health of ‘left behind’ elderly parents, research on the consequences of children’s migration on the mental health and well-being of elderly parents left behind is inconclusive and a systematic review is warranted.

Objectives

To identify the association between the left behind or empty nest status and the mental health of older parents, and to identify common risk factors for poor mental health among those left behind.

Methods

Online databases CINAHL, PsycINFO, PubMed, Scopus and ProQuest were searched for research (2000-September 2017) that focused on the relationship between the migration of adult children and the mental health of the older parents (≥50 years) left behind. The JBI Checklist for Analytical Cross Sectional Studies was used to assess the methodological quality of the articles.

Results

25 articles met the inclusion criteria. The studies identified that left behind older parents had higher levels of mental health problems compared to non-left behind. Left behind parents had higher depressive symptoms, higher levels of loneliness, lower life satisfaction, lower cognitive ability and poorer psychological health. A number of risk factors were identified for mental health disorders among the left behind parents, which included living arrangements, gender, education, income, physical health status, physical activity, family and social support, age, rural residence and frequency of children’s visit.

Conclusions

This review synthesised the various studies related to the mental health of left behind parents, advancing the theoretical and empirical understanding of the implications of out-migration of adult children on the psychological health and well-being of older parents. More responsive preventive measures and effective management approaches are required for this vulnerable cohort.

Compression of cognitive morbidity by higher education in individuals aged 75+ living in Germany

BACKGROUND

Previous studies have shown that higher education may reduce dementia risk and promote a better cognitive functioning in older age.

OBJECTIVE

The study investigated to what extent higher education leads to compression of cognitive morbidity, and thus a shorter lifetime affected by cognitive impairment and dementia, in individuals aged 75 years and older living in Germany.

METHODS

Our sample included n = 742 individuals of the population-based Leipzig Longitudinal Study of the Aged (LEILA75+; 1998-2013), who were free of dementia at baseline. The impact of higher education on compression of cognitive morbidity was studied by analyzing the association between education and (1) cognitive functioning over the study period and age at dementia onset, (2) age at death, and (3) the cumulative lifetime cognitive morbidity.

RESULTS

Individuals with more years of education had a higher cumulative cognitive functioning over the lifetime period 75 to 100 years (weighted for survival probability), but not a later age of dementia onset nor a later age at death.

CONCLUSION

Our results suggest, in individuals aged 75 years and older, higher education only compresses cognitive morbidity prior to dementia onset. Findings may be specific to countries where education is not a necessary requirement for access to good quality health care services.

Patient characteristics associated with screening positive for Alzheimer's disease and related dementia

INTRODUCTION

Screening all older adults for Alzheimer's disease and related dementias (ADRD) in primary care may not be acceptable or feasible. The goal of this study was to identify factors that could optimize screening in primary care and enhance its feasibility.

METHODS

This is a cross-sectional study in rural, suburban, and urban primary care practices in Indiana. A total of 1,723 patients ≥65 years of age were screened for ADRD using the Memory Impairment Screen. Logistic regression was used to identify patient-specific factors associated with screening positive for ADRD.

RESULTS

The positive screening rate was 4.9%. Rates varied significantly across the three study sites. The rural site had the lowest rate (2.8%), which was significantly lower than the rates at the suburban (5.6%) and urban (6.6%) sites (P<0.01). Patient age, sex, and education were significantly (P<0.05) associated with screening positive for ADRD.

CONCLUSION

Targeted screening of patients at risk for ADRD may represent a more optimal and feasible screening alternative to population screening.

Prevalence of pain-related diagnoses in patients with dementia: a nationwide study

Purposes

To investigate the prevalence of pain-related diagnoses in patients with dementia and evaluate the association of pain-related diagnoses with demographic characteristics and dementia subtypes.

Patients and methods

In this population-based retrospective cohort study, participants were recruited from a cohort of 2 million people randomly sampled from the general population in the National Health Insurance Research Database of Taiwan from 2000 to 2013. The index year was defined as the period of 1 year from the date of the first diagnosis of dementia.

Results

The study group comprised 28,450 patients with the dementia subtypes of vascular dementia, Alzheimer’s disease, or other dementia subtypes. The mean age of patients with dementia was 76.75 years. Of all patients with dementia, 49.07% had at least one pain-related diagnosis documented in their outpatient or inpatient claim records within the index year. The top three pain-related diagnoses were osteoarthritis (29.27%), headache (12.53%), and osteoporosis (11.43%). Musculoskeletal diagnosis was more likely in female patients with vascular dementia. Although patients with vascular dementia had a significantly lower prevalence of pain-related diagnosis, they had a significantly higher risk of 1-year mortality than patients with other dementia subtypes.

Conclusion

During the index year, 49.07% of patients with dementia had at least one pain-related diagnosis. To investigate the differences of the use of pain medication in patients with different dementia subtypes and the difference of pain-related diagnosis and treatment in patients with and without dementia, future studies are recommended.

Exposure to Environmental and Occupational Particulate Air Pollution as a Potential Contributor to Neurodegeneration and Diabetes: A Systematic Review of Epidemiological Research

It has been hypothesised that environmental air pollution, especially airborne particles, is a risk factor for type 2 diabetes mellitus (T2DM) and neurodegenerative conditions. However, epidemiological evidence is inconsistent and has not been previously evaluated as part of a systematic review. Our objectives were to carry out a systematic review of the epidemiological evidence on the association between long-term exposure to ambient air pollution and T2DM and neurodegenerative diseases in adults and to identify if workplace exposures to particles are associated with an increased risk of T2DM and neurodegenerative diseases. Assessment of the quality of the evidence was carried out using the GRADE system, which considers the quality of the studies, consistency, directness, effect size, and publication bias. Available evidence indicates a consistent positive association between ambient air pollution and both T2DM and neurodegeneration risk, such as dementia and a general decline in cognition. However, corresponding evidence for workplace exposures are lacking. Further research is required to identify the link and mechanisms associated with particulate exposure and disease pathogenesis and to investigate the risks in occupational populations. Additional steps are needed to reduce air pollution levels and possibly also in the workplace environment to decrease the incidence of T2DM and cognitive decline.

Cognitive Aging in Black and White Americans: Cognition, Cognitive Decline, and Incidence of Alzheimer Disease Dementia

BACKGROUND

US-based studies have reported that older blacks perform worse than older whites on cognitive tests and have higher risk of Alzheimer disease dementia (AD). It is unclear whether these findings reflect differences in cognitive decline.

METHODS

The Chicago Health and Aging Project followed individuals, 65+ years old (64% black, 36% white), for up to 18 years. Participants underwent triennial cognitive assessments; stratified randomized samples underwent assessments for AD. We compared black and white participants' cognitive performance, cognitive decline rate (N = 7,735), and AD incidence (N = 2,144), adjusting for age and sex.

RESULTS

Black participants performed worse than white participants on the cognitive tests; 441 participants developed AD. Black participants' incident AD risk was twice that of whites (RR = 1.9; 95% CI, 1.4, 2.7), with 58 excess cases/1,000 occurring among blacks (95% CI, 28, 88). Among noncarriers of APOE ε4, blacks had 2.3 times the AD risk (95% CI, 1.5, 3.6), but among carriers, race was not associated with risk (RR = 1.1; 95% CI, 0.6, 2.0; Pinteraction = 0.05). However, cognitive decline was not faster among blacks: the black-white difference in 5-year change in global cognitive score was 0.007 standard unit (95% CI, -0.034, 0.047). Years of education accounted for a sizable portion of racial disparities in cognitive level and AD risk, in analyses using a counterfactual approach.

CONCLUSIONS

The higher risk of AD among blacks may stem from lower level of cognitive test performance persisting throughout the observation period rather than faster rate of late-life cognitive decline. Disparities in educational attainment may contribute to these performance disparities. See video abstract at, http://links.lww.com/EDE/B299.

Examining the Relationship between Trace Lithium in Drinking Water and the Rising Rates of Age-Adjusted Alzheimer's Disease Mortality in Texas

Background:

Alzheimer’s disease (AD) mortality rates have steadily increased over time. Lithium, the current gold standard treatment for bipolar disorder, can exert neuroprotective effects against AD.

Objective:

We examined the relationship between trace levels of lithium in drinking water and changes in AD mortality across several Texas counties.

Methods:

6,180 water samples from public wells since 2007 were obtained and averaged for 234 of 254 Texas counties. Changes in AD mortality rates were calculated by subtracting aggregated age-adjusted mortality rates obtained between 2000–2006 from those obtained between 2009–2015. Using aggregated rates maximized the number of counties with reliable mortality data. Correlational analyses between average lithium concentrations and changes in AD mortality were performed while also adjusting for gender, race, education, rural living, air pollution, physical inactivity, obesity, and type 2 diabetes.

Results:

Age-adjusted AD mortality rate was significantly increased over time (+27%, p < 0.001). Changes in AD mortality were negatively correlated with trace lithium levels (p = 0.01, r = –0.20), and statistical significance was maintained after controlling for most risk factors except for physical inactivity, obesity, and type 2 diabetes. Furthermore, the prevalence of obesity and type 2 diabetes positively correlated with changes in AD mortality (p = 0.01 and 0.03, respectively), but also negatively correlated with trace lithium in drinking water (p = 0.05 and <0.0001, respectively).

Conclusion:

Trace lithium in water is negatively linked with changes in AD mortality, as well as obesity and type 2 diabetes, which are important risk factors for AD.

Effects of sex, educational background, and chronic kidney disease grading on longitudinal cognitive and functional decline in patients in the Japanese Alzheimer's Disease Neuroimaging Initiative study

Introduction

The objective of this study was to determine whether sex or education level affects the longitudinal rate of cognitive decline in Japanese patients in the Alzheimer's disease Neuroimaging Initiative study with defined mild cognitive impairment (MCI).

Methods

We accessed the entire Japanese Alzheimer's Disease Neuroimaging Initiative data set of 537 individuals, among whom 234 had MCI and 149 had Alzheimer's disease. We classified participants into three categories of educational history: (1) low, 0 to 9 years; (2) moderate, 10 to 15 years; and (3) high ≥16 years. We examined the main effects and interactions of visit, sex, and educational achievement on scores for the Clinical Dementia Rating Sum of Boxes, Alzheimer's Disease Assessment Scale–cognitive subscale 13, Mini-Mental State Examination, and Functional Activities Questionnaire in a longitudinal manner.

Results

Women with MCI had a significantly faster rate of decline than men over a 3-year period. Highly educated men showed a significantly slower rate of decline than the other groups. Sex differences in the rates of decline remained after stratification by amyloid or apolipoprotein E (APOE) ε4 status but were absent in Alzheimer's disease over a 2-year period. Subtle differences in chronic kidney disease grade affected the rate of decline. A higher Fazekas periventricular hyperintensity score was associated with a lower estimated glomerular filtration rate in women only.

Discussion

In patients with MCI, sex and educational history significantly affected the rate of change in cognitive and clinical assessments. Furthermore, a subtle decline in chronic kidney disease grade was associated with a faster rate of decline regardless of amyloid pathology in women.

World dementia: One approach does not fit all

OBJECTIVE

To highlight the broad global diversity in the diagnosis, management, and research of dementia in different regions of the world.

METHODS

A critical review of the limited literature from the global South compared with advances that have emerged from key studies in the West and observations from the authors' experiences.

RESULTS

The last several decades have witnessed major advances in dementia research and include an understanding of epidemiologic trends in the global burden of disease, the development of biomarkers for Alzheimer disease, the identification of novel therapeutic targets, and the recognition of the role of protective life-course experiential factors. For the effective translation of these research advances into societies, a "world approach" to dementia is vital. Developing societies substantially differ from Western countries in their attitudes toward dementia, as well as their clinical manifestations and risk factor profiles, marked by lower education and socioeconomic status, a higher cardiovascular disease burden, and genetic variability. Emerging evidence emphasizes the interaction among ethnicity, genetics, epigenetics, environment, culture, and neurobiology in influencing manifestations of dementia. Therefore, the investigation of dementia in diverse settings, including a more global perspective, is crucial for a comprehensive understanding of the condition as well as the identification of novel solutions.

CONCLUSIONS

A world approach to dementia provides an opportunity to understand, manage, coordinate, and begin to prevent dementia through an integrated approach based on firm scientific evidence.

Associations between birth characteristics and age-related cognitive impairment and dementia: A registry-based cohort study

BACKGROUND

There is evidence for long-lasting effects of birth characteristics on cognitive ability in childhood and adulthood. Further, low cognitive ability throughout the lifetime has been linked to age-related cognitive decline and dementia risk. However, little is known about the effects of birth characteristics on cognitive dysfunction late in life. Here we explore potential associations between birth characteristics (weight, head circumference, length, and gestational age), adjusted and not adjusted for gestational age, and cognitive impairment and dementia late in life.

METHODS AND FINDINGS

Data from twins in the Swedish Twin Registry born 1926-1960 were merged with information from the Swedish birth, patient, and cause of death registries, resulting in a sample of 35,191 individuals. A subsample of 4,000 twins aged 65 years and older also participated in a telephone cognitive screening in 1998-2002. Associations of birth characteristics with registry-based dementia diagnoses and on telephone-assessed cognitive impairment were investigated in the full sample and subsample, respectively. The full sample contained 907 (2.6%) individuals with a dementia diagnosis (an incidence rate of 5.9% per 100,000 person-years), 803 (2.4%) individuals born small for gestational age, and 929 (2.8%) individuals born with a small head for gestational age. The subsample contained 569 (14.2%) individuals with cognitive impairment. Low birth weight for gestational age and being born with a small head for gestational age were significant risk factors for cognitive dysfunction late in life, with an up to 2-fold risk increase (p < 0.001) compared to infants with normal growth and head size, even after controlling for familial factors, childhood socioeconomic status, and education in adulthood. In line with this, each additional 100 g birth weight and each additional millimeter head circumference significantly reduced the risk for dementia (hazard ratio 0.98, 95% confidence interval 0.97 to 0.99, p = 0.004) and cognitive impairment (odds ratio 0.99, 95% confidence interval 0.99 to 1.00, p = 0.004), respectively. Within-pair analyses of identical twins, though hampered by small sample size, suggested that the observed associations between birth characteristics and dementia are likely not due to underlying shared genetic or environmental etiology. A limitation of the present study is that registry-based dementia diagnoses likely miss some of the true dementia cases in the population. Further, a more precise measure of cognitive reserve early in life as well as a date of onset for the cognitive impairment measure in the subsample would have been favorable.

CONCLUSIONS

In this study, we found that infants of smaller birth size (i.e., low birth weight or small head circumference adjusted and unadjusted for gestational age) have a significantly higher risk of age-related cognitive dysfunction compared to those with normal growth, highlighting the importance of closely monitoring the cognitive development of such infants and evaluating the potential of early life interventions targeted at enhancing cognitive reserve.

Individual and Area-Based Socioeconomic Factors Associated With Dementia Incidence in England: Evidence From a 12-Year Follow-up in the English Longitudinal Study of Ageing

IMPORTANCE

Lower educational attainment is associated with a higher risk of dementia. However, less clear is the extent to which other socioeconomic markers contribute to dementia risk.

OBJECTIVE

To examine the relationship of education, wealth, and area-based deprivation with the incidence of dementia over the last decade in England and investigate differences between people born in different periods.

DESIGN, SETTING, AND PARTICIPANTS

Data from the English Longitudinal Study of Ageing, a prospective cohort study that is representative of the English population, were used to investigate the associations between markers of socioeconomic status (wealth quintiles and the index of multiple deprivation) and dementia incidence. To investigate outcomes associated with age cohorts, 2 independent groups were derived using a median split (born between 1902-1925 and 1926-1943).

MAIN OUTCOMES AND MEASURES

Dementia as determined by physician diagnosis and the Informant Questionnaire on Cognitive Decline in the Elderly.

RESULTS

A total of 6220 individuals aged 65 years and older enrolled in the study (median [interquartile range] age at baseline, 73.2 [68.1-78.3] years; 3410 [54.8%] female). Of these, 463 individuals (7.4%) had new cases of dementia ascertained in the 12 years between 2002-2003 and 2014-2015. In the cohort born between 1926 and 1943, the hazard of developing dementia was 1.68 times higher (hazard ratio [HR] = 1.68 [95% CI, 1.05-2.86]) for those in the lowest wealth quintile compared with those in the highest quintile, independent of education, index of multiple deprivation, and health indicators. Higher hazards were also observed for those in the second-highest quintile of index of multiple deprivation (HR = 1.62 [95% CI, 1.06-2.46]) compared with those in the lowest (least deprived) quintile.

CONCLUSIONS AND RELEVANCE

In an English nationally representative sample, the incidence of dementia appeared to be socioeconomically patterned primarily by the level of wealth. This association was somewhat stronger for participants born in later years.

Red blood cell indices and anaemia as causative factors for cognitive function deficits and for Alzheimer's disease

BACKGROUND

Studies have shown that low haemoglobin and anaemia are associated with poor cognition, and anaemia is known to be associated with Alzheimer's disease (AD), but the mechanism of this risk is unknown. Here, we first seek to confirm the association between cognition and anaemia and secondly, in order to further understand the mechanism of this association, to estimate the direction of causation using Mendelian randomisation.

METHODS

Two independent cohorts were used in this analysis: AddNeuroMed, a longitudinal study of 738 subjects including AD and age-matched controls with blood cell measures, cognitive assessments and gene expression data from blood; and UK Biobank, a study of 502,649 healthy participants, aged 40-69 years with cognitive test measures and blood cell indices at baseline. General linear models were calculated using cognitive function as the outcome with correction for age, sex and education. In UK Biobank, SNPs with known blood cell measure associations were analysed with Mendelian randomisation to estimate direction of causality. In AddNeuroMed, gene expression data was used in pathway enrichment analysis to identify associations reflecting biological function.

RESULTS

Both sample sets evidence a reproducible association between cognitive performance and mean corpuscular haemoglobin (MCH), a measure of average mass of haemoglobin per red blood cell. Furthermore, in the AddNeuroMed cohort, where longitudinal samples were available, we showed a greater decline in red blood cell indices for AD patients when compared to controls (p values between 0.05 and 10-6). In the UK Biobank cohort, we found lower haemoglobin in participants with reduced cognitive function. There was a significant association for MCH and red blood cell distribution width (RDW, a measure of cell volume variability) compared to four cognitive function tests including reaction time and reasoning (p < 0.0001). Using Mendelian randomisation, we then showed a significant effect of MCH on the verbal-numeric and numeric traits, implying that anaemia has causative effect on cognitive performance.

CONCLUSIONS

Lower haemoglobin levels in blood are associated to poor cognitive function and AD. We have used UK Biobank SNP data to determine the relationship between cognitive testing and haemoglobin measures and suggest that haemoglobin level and therefore anaemia does have a primary causal impact on cognitive performance.

Comparative Effects of Education and Bilingualism on the Onset of Mild Cognitive Impairment

BACKGROUND

Increasing evidence suggests that life course factors such as education and bilingualism may have a protective role against dementia due to Alzheimer disease. This study aimed to compare the effects of education and bilingualism on the onset of cognitive decline at the stage of mild cognitive impairment (MCI).

METHODS

A total of 115 patients with MCI evaluated in a specialty memory clinic in Hyderabad, India, formed the cohort. MCI was diagnosed according to Petersen's criteria following clinical evaluation and brain imaging. Age at onset of MCI was compared between bilinguals and monolinguals, and across subjects with high and low levels of education, adjusting for possible confounding variables.

RESULTS

The bilingual MCI patients were found to have a clinical onset of cognitive complaints 7.4 years later than monolinguals (65.2 vs. 58.1 years; p = 0.004), while years of education was not associated with delayed onset (1-10 years of education, 59.1 years; 11-15 years of education, 62.6 years; >15 years of education, 62.2 years; p = 0.426).

CONCLUSION

The effect of bilingualism is protective against cognitive decline, and lies along a continuum from normal to pathological states. In comparison, the role of years of education is less robust.

Feasibility and Safety of Perilla Seed Oil as an Additional Antioxidative Therapy in Patients with Mild to Moderate Dementia

Dementia is a broad-spectrum terminology for a degenerate in cognitive function severe enough to intervene in activities of daily living. Oxidative stress plays a major role in the neurodegenerative cascade, leading to the irreversible mechanism in dementia. Perilla seed oil is extracted from its seeds and contains a high source of antioxidative substances such as omega-3 fatty acid. With its prominent antioxidative property, perilla seed oil demonstrates neuroprotective effects against dementia in preclinical studies. We aim to prove the feasibility and safety of perilla seed oil as an additional antioxidative therapy in patients with dementia. This single-centered, double-blinded, placebo-controlled trial randomized 239 patients with clinical diagnosis of mild to moderate dementia according to the Thai Mini-Mental State Examination (TMSE) score of 10 to 23 or the Thai Montreal Cognitive Assessment score of 12 to 25. Either two capsules containing 500 milligrams of perilla seed oil or similarly appearing two capsules containing 500 milligrams of olive oil (placebo) four times daily was added to conventional standard treatment of dementia for six months. Clinical side effects and routine laboratory results at baseline and after treatment were compared between both groups. Nausea and vomiting were the most common clinical side effects (3%) found equally in both groups. Three patients in the placebo group prematurely discontinued the medication, while only one patient in the treatment group quit the medication early. However, about 5% of patients in both groups could not comply with the regimen of the treatment. The routine laboratory results, including complete blood counts, kidney function tests, and liver function panels, at baseline and after treatment, were not significantly different in both groups. In conclusion, perilla seed oil was feasible and safe to add on with standard treatment in patients with mild to moderate dementia. Further study is needed to confirm its benefit to use as additional antioxidative therapy in patients with dementia.

Development and initial validation of the Retrospective Indigenous Childhood Enrichment scale (RICE)

ABSTRACTBackground:Years of education is the most commonly used proxy measure of cognitive reserve. Other forms of cognitive stimulation in childhood may provide similar protection against cognitive decline, particularly in Indigenous groups, where education may have been lacking in quality or quantity. The Retrospective Indigenous Childhood Enrichment (RICE) scale was developed to measure non-school-based activities and environmental stimulation during childhood that are likely to have enhanced cognitive reserve. The aim of the study was to assess the validity and reliability of the RICE scale with a group of older Aboriginal Australians.

METHODS

294 Aboriginal Australian people (60-92 years), living in urban or regional areas of NSW, completed the RICE scale as part of a longer face-to-face interview. Additional data was collected on their formal education, childhood environment, and childhood trauma (Study 1). Test-retest, inter-method and inter-rater reliability were assessed in a convenience sample of a further 38 participants by re-administration of the RICE scale at two time points, approximately 14 days apart (M = 14.11, SD = 6.78) (Study 2).

RESULTS

Factor analyses reduced the scale from 21 items to 18 and identified three factors: (1) Traditional, (2) Intellectual, and (3) Community. Higher scores on the RICE scale were related to higher years of formal education and lower scores on a childhood trauma questionnaire. The RICE scale had good internal consistency (Cronbach's α 0.79), and excellent test-retest reliability (ICC = 0.95, 95% CI 0.90-0.97) and inter-rater reliability (0.99, CI 95% 0.997-0.999).

CONCLUSIONS

The RICE is, to our knowledge, the first standardized measure that assesses the level of childhood environmental stimulation in older Aboriginal Australians. This could provide an important supplementary measure, in addition to formal education, to investigate cognitive reserve and dementia risk in this population and enhance understanding of the links between childhood experiences and late-life cognitive decline.

Progress and Challenges in the Diagnosis of Dementia: A Critical Review

Longer life expectancies have led to an increased number of neurodegenerative disease cases globally. Accurate diagnosis of this devastating disorder is of crucial importance but is still feasible only by a brain biopsy after death. An enormous amount of attention and research has been in place over the years toward the better understanding of the mechanisms, as well as the early diagnosis, of neurodegeneration. However, numerous studies have been contradictory from time to time, while new diagnostic methods are constantly developed in a tireless effort to tackle the disease. Nonetheless, there is not yet a conclusive report covering a broader range of techniques for the diagnosis of different types of dementia. In this paper, we critically review current knowledge on the different hypotheses about the pathogenesis of distinct types of dementia, as well as risk factors and current diagnostic approaches in a clinical setting, including neuroimaging, cerebrospinal (CSF), and blood tests. Encouraging research results for the diagnosis and investigation of neurodegenerative disorders are also reported. Particular attention is given to the field of spectroscopy as an emerging tool to detect dementias, follow-up patients, and potentially monitor the patients' response to a therapeutic approach. Spectroscopic techniques, such as infrared and Raman spectroscopy, have facilitated numerous disease-related studies, including neurodegenerative disorders, and are currently undergoing trials for clinical implementation. This review constitutes a comprehensive report with an in-depth focus on promising imaging, molecular biomarker and spectroscopic tests in the field of dementive diseases.

Dementia worry in middle-aged and older adults in Germany: sociodemographic, health-related and psychological correlates

"Dementia worry" (DW; i.e., concern about developing dementia) is highly prevalent in the general population. However, research on the characteristics associated with lower and higher levels of DW is still limited. Based on previous empirical and conceptual work, we examined the extent to which DW was related to a comprehensive range of objective and subjective characteristics (sociodemographics, contact with people with dementia, physical health-related risk factors, well-being/psychological distress, aging self-perceptions, social-cognitive health beliefs about dementia). A convenience sample of N = 219 German adults 40 + years (M = 65.50 years, SD = 11.34; 40-94 years) reporting no dementia or cognitive impairment diagnosis completed questionnaires. We improved upon previous research by using a ten-item scale to measure DW. We used bivariate correlations and multivariate regression to examine the extent to which DW was related to the potential concomitants. 41.1% of the participants indicated DW. Together, the predictor variables explained 53.3% of the variance in DW. DW was related to psychological distress, perceived memory change, aging anxiety, and personal risk perception in both the bivariate and multivariate analyses. There was a quadratic (reverse U shape) relationship between age and DW. Physical health-related risk factors were not related to DW. Our findings suggest that DW represents a hybrid of psychological distress, aging self-perceptions, and a specific type of health concern. Healthcare practitioners should consider a person's psychological characteristics when deciding how to intervene when someone indicates moderate or high DW.

Comparing Approaches to Optimize Cut-off Scores for Short Cognitive Screening Instruments in Mild Cognitive Impairment and Dementia

BACKGROUND

Although required to improve the usability of cognitive screening instruments (CSIs), the use of cut-off scores is controversial yet poorly researched.

OBJECTIVE

To explore cut-off scores for two short CSIs: the Standardized Mini-Mental State Examination (SMMSE) and Quick Mild Cognitive Impairment (Qmci) screen, describing adjustments in scores for diagnosis (MCI or dementia), age (≤, >75 years), and education (<, ≥12 years), comparing two methods: the maximal accuracy approach, derived from receiver operating characteristic curves, and Youden's Index.

METHODS

Pooled analysis of assessments from patients attending memory clinics in Canada between 1999-2010 : 766 with mild cognitive impairment (MCI) and 1,746 with dementia, and 875 normal controls.

RESULTS

The Qmci was more accurate than the SMMSE in differentiating controls from MCI or cognitive impairment (MCI and dementia). Employing the maximal accuracy approach, the optimal SMMSE cut-off for cognitive impairment was <28/30 (AUC 0.86, sensitivity 74%, specificity 88%) versus <63/100 for the Qmci (AUC 0.93, sensitivity 85%, specificity 85%). Using Youden's Index, the optimal SMMSE cut-off remained <28/30 but fell slightly to <62/100 for the Qmci (sensitivity 83%, specificity 87%). The optimal cut-off for MCI was <29/30 for the SMMSE and <67/100 for the Qmci, irrespective of technique. The maximal accuracy approach generally produced higher Qmci cut-offs than Youden's Index, both requiring adjustment for age and education. There were no clinically meaningful differences in SMMSE cut-off scores by age and education or method employed.

CONCLUSION

Caution should be exercised selecting cut-offs as these differ by age, education, and method of derivation, with the extent of adjustment varying between CSIs.

Online assessment of risk factors for dementia and cognitive function in healthy adults

OBJECTIVE

Several potentially modifiable risk factors for cognitive decline and dementia have been identified, including low educational attainment, smoking, diabetes, physical inactivity, hypertension, midlife obesity, depression, and perceived social isolation. Managing these risk factors in late midlife and older age may help reduce the risk of dementia; however, it is unclear whether these factors also relate to cognitive performance in older individuals without dementia.

METHOD

Data from 14 201 non-demented individuals aged >50 years who enrolled in the online PROTECT study were used to examine the relationship between cognitive function and known modifiable risk factors for dementia. Multivariate regression analyses were conducted on 4 cognitive outcomes assessing verbal and spatial working memory, visual episodic memory, and verbal reasoning.

RESULTS

Increasing age was associated with reduced performance across all tasks. Higher educational achievement, the presence of a close confiding relationship, and moderate alcohol intake were associated with benefits across all 4 cognitive tasks, and exercise was associated with better performance on verbal reasoning and verbal working memory tasks. A diagnosis of depression was negatively associated with performance on visual episodic memory and working memory tasks, whereas being underweight negatively affected performance on all tasks apart from verbal working memory. A history of stroke was negatively associated with verbal reasoning and working memory performance.

CONCLUSION

Known modifiable risk factors for dementia are associated with cognitive performance in non-demented individuals in late midlife and older age. This provides further support for public health interventions that seek to manage these risk factors across the lifespan.

Risk of progression from subjective cognitive decline to mild cognitive impairment: The role of study setting

INTRODUCTION

We compared risk of progression from subjective cognitive decline (SCD) to mild cognitive impairment (MCI) in an academic memory clinic versus a population-based study.

METHODS

Older adults presenting at a memory clinic were classified as SCD (n = 113) or as noncomplainers (n = 82). Participants from a population study were classified as SCD (n = 592) and noncomplainers (n = 589) based on a memory complaint score. Annual follow-up performed for a mean of 3 years.

RESULTS

The adjusted hazard ratio for SCD was 15.97 (95% confidence interval: 6.08-42.02, P < .001) in the memory clinic versus 1.18 (95% confidence interval: 1.00-1.40, P = .047) in the population study, where reported "worry" about memory further increased SCD-associated risk for MCI.

DISCUSSION

SCD is more likely to progress to MCI in a memory clinic than the general population; participants' characteristics vary across settings. Study setting should be considered when evaluating SCD as a risk state for MCI and dementia.

The value of a year's general education for reducing the symptoms of dementia

We present a method for estimating the benefits of years of education for reducing dementia symptoms based on the cost savings that would accrue from continuing independent living rather than relying on formal or informal carers. Our method for estimating the benefits of education involves three steps: first taking a year of education and seeing how much this lowers dementia, second using this dementia reduction and estimating how much independent living is affected and third applying the change in caregiving costs associated with the independent living change. We apply our method for estimating education benefits to a National Alzheimer's Coordinating Center sample of 17,239 participants at 32 US Alzheimer's disease centres over the period September 2005 and May 2015.

The association between macronutrient intake and cognition in individuals aged under 65 in China: a cross-sectional study

OBJECTIVE

The aim of this retrospective study was to explore the correlation between daily energy intake from macronutrients and cognitive functions in a Chinese population aged less than 65 years.

DESIGN

This is a cross-sectional study to explore the relationships between macronutrients' intake and cognitive function. The analysis of variance (ANOVA) and χ² test were used to compare the demographic and physical characteristics, lifestyle and laboratory parameters with the intake of macronutrients among different quartiles of % fat/energy. Multivariate logistic regression analysis was applied to identify the potential risk factors of mild cognitive impairment (MCI).

PARTICIPANTS

Young and middle-aged participants (age <65 years) were recruited from Beijing, China. The Montreal cognitive assessment (MoCA) and mini-mental state examination (MMSE) were used to evaluate the cognitive functions, and the dietary intake of the participants was estimated with a semi-quantitative food frequency questionnaire (FFQ).

RESULTS

Among the 661 participants, 80 (12.1%) had MCI, while 581 (87.9%) had normal cognitive functions. On evaluating the data based on the age group, educational background, and conditions of hyperlipidaemia and total energy intake, the results revealed that high % fat (upper quartile: adjusted OR (aOR) 3.90, 95% CI1.53 to 9.89, P=0.004), and high % protein intake (upper quartile: aOR 2.77, 95% CI 1.24 to 6.15) were greatly associated with increased frequency of MCI, while high % carbohydrate intake (upper quartile: aOR0.30, 95% CI 0.12 to 0.72) was correlated with decreased prevalence of MCI.

CONCLUSION

The dietary pattern with high percentage of energy intake from fat and protein, and low-energy intake from carbohydrate might have been associated with cognitive decline in a Chinese population under 65 years of age.

Screening of Dementia in Portuguese Primary Care: Methodology, Assessment Tools, and Main Results

The objectives of this article are as follows: (1) to describe the assessment protocol used to outline people with probable dementia in Primary Health Care; (2) to show the methodological design and procedure to obtain a representative sample of patients with probable dementia; and (3) to report the main characteristics of the sample collected in the context of the study "Characteristics and needs of people with probable dementia." The study protocol was based on the "Community Assessment of Risk and Treatment Strategies (CARTS) Program" and is composed by a set of instruments that allow the assessment of older adults with probable dementia in several areas (health, psychological, functionality, and other). Descriptive analysis was used to characterize the final sample (n = 436). The study protocol as well as the methodological procedure to obtain the referral of research participants and data collection on the condition of people with probable dementia in Primary Health Care proved to be a valuable tool to obtain a sample of patients distributed by the full range of probable dementia in a large geographical area. Results may allocate the design of care pathways for old people with cognitive disorders to prevent, delay impairment, and/or optimize quality of life of patients.