Prevalence of dementia and cognitive impairment in Southeastern Spain: the Ariadna study

The prevalence of mild cognitive impairment and dementia among rural dwellers: A systematic review and meta-analysis

The mild cognitive impairment (MCI) and dementia in rural areas are increasingly attracting public attention. However, their prevalence is still unclear. This study aims to reveal the distribution of MCI and dementia in rural areas. We systematically searched PubMed, Web of Science, Embase, and PsycINFO up to June 2023 for cohort and cross-sectional studies. Meta-analysis was conducted using random-effects models to evaluate the prevalence of MCI and dementia. Thirty-five studies with 16,936 participants met the inclusion criteria. The pooled prevalence of MCI and dementia was 27 % (n = 12, 95 %CI = 0.21-0.32, I2 = 99.5 %, P < 0.001) and 7 % (n = 27, 95 %CI = 0.05-0.08, I2 = 99.30 %, P < 0.001), respectively. Subgroup analyses revealed that aged 60 years or older [(MCI: 29 %, 95 %CI = 0.20-0.38, I2 = 99.7 %, P < 0.001), (dementia: 9 % (95 %CI = 0.06-0.12, I2 = 99 %, P < 0.001)], female [(MCI: 29 %, 95 %CI = 0.19-0.40, I2 = 99.3 %, P < 0.001), (dementia: 7 %, 95 % CI = 0.04-0.12, I2 = 98.66 %, P < 0.001)], a-MCI (19 %, 95 %CI = 0.12-0.26, I2 = 97.62 %, P < 0.001) and AD (4 %, 95 %CI = 0.02-0.05, I2 = 98.60 %, P < 0.001) showed higher prevalence. The prevalence of MCI and dementia in rural China was 23 % (95 %CI = 0.18-0.29, I2 = 99.5 %, P < 0.001) and 6 % (95 %CI = 0.04-0.08, I2 = 99.6 %, P < 0.001), respectively. Implementing cognitive impairment screening and intervention measures is necessary to improve the cognitive function of the rural population.

Prevalence, cognitive characteristics, and influencing factors of amnestic mild cognitive impairment among older adults residing in an urban community in Chengdu, China

Objective

Dementia is a significant public health concern, and mild cognitive impairment (MCI) serves as a transitional stage between normal aging and dementia. Among the various types of MCI, amnestic MCI (aMCI) has been identified as having a higher likelihood of progressing to Alzheimer's dimension. However, limited research has been conducted on the prevalence of aMCI in China. Therefore, the objective of this study is to investigate the prevalence of aMCI, examine its cognitive characteristics, and identify associated risk factors.

Methods

In this cross-sectional study, we investigated a sample of 368 older adults aged 60 years and above in the urban communities of Chengdu, China. The participants underwent a battery of neuropsychological assessments, including the Mini-Mental State Examination (MMSE), the Clinical Dementia Rating (CDR), Auditory Verbal Learning Test (AVLT), Wechsler's Logical Memory Task (LMT), Boston Naming Test (BNT) and Trail Making Test Part A (TMT-A). Social information was collected by standard questionnaire. Multiple logistic regression analysis was utilized to screen for the risk and protective factors of aMCI.

Results

The data analysis included 309 subjects with normal cognitive function and 59 with aMCI, resulting in a prevalence of 16.0% for aMCI. The average age of participants was 69.06 ± 7.30 years, with 56.0% being females. After controlling for age, gender and education, the Spearman partial correlation coefficient between various cognitive assessments and aMCI ranged from -0.52 for the long-term delayed recall scores in AVLT to 0.19 for the time-usage scores in TMT-A. The results indicated that all cognitive domains, except for naming scores (after semantic cue of BNT) and error quantity (in TMT-A), showed statistically significant associations with aMCI. Furthermore, the multiple logistic regression analysis revealed that older age (OR = 1.044, 95%CI: 1.002~1.087), lower educational level, and diabetes (OR = 2.450, 95%CI: 1.246~4.818) were risk factors of aMCI.

Conclusion

This study found a high prevalence of aMCI among older adults in Chengdu, China. Individuals with aMCI exhibited lower cognitive function in memory, language, and executive domains, with long-term delayed recall showing the strongest association. Clinicians should prioritize individuals with verbal learning and memory difficulties, especially long-term delayed recall, in clinical practice.

Analysis of Convergent Validity of Performance-Based Activities of Daily Living Assessed by PA-IADL Test in Relation to Traditional (Standard) Cognitive Assessment to Identify Older Adults with Mild Cognitive Impairment

Difficulty in performing instrumental activities of daily living (IADLs) is currently considered an important indicator of cognitive impairment in the elderly. A non-experimental case-control investigation was conducted to assess the convergent validity of the PA-IADL with traditional (standard) cognitive assessment tests in its ability to identify adults with mild cognitive impairment. The analysis of the data was carried out by means of various multivariate statistical tests, and the sequence in its execution led to the conclusion that 8 of the 12 Tasks that make up the PA-IADL allow for the identification of people with mild cognitive impairment (MCI) to the same extent as traditional cognitive assessment tests and regardless of age. Age was found to be a moderating variable in the performance of the eight tasks; however, the results allow us to hypothesize that people with MCI experience a significant decline when it happens but thereafter, the deterioration that occurs does so at the same rate as the deterioration experienced by healthy people. They also allow us to hypothesize that the difference in the cognitive skills required by the eight functional tasks, and therefore also in the cognitive skills required by the traditional (standard) tests of a person with MCI compared to a person of the same age without MCI (Healthy), is approximately 10 years. These hypotheses have remarkable relevance and should be tested via longitudinal research. In the meantime, the results highlight the importance of the IADL assessment for the diagnosis of MCI as a complement to the standard cognitive assessment.

A prediction model of cognitive impairment risk in elderly illiterate Chinese women

Objective

To establish and validate a targeted model for the prediction of cognitive impairment in elderly illiterate Chinese women.

Methods

1864 participants in the 2011-2014 cohort and 1,060 participants in the 2014-2018 cohort from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) were included in this study. The Chinese version of the Mini-Mental State Examination (MMSE) was used to measure cognitive function. Demographics and lifestyle information were collected to construct a risk prediction model by a restricted cubic spline Cox regression. The discrimination and accuracy of the model were assessed by the area under the curve (AUC) and the concordance index, respectively.

Results

A total of seven critical variables were included in the final prediction model for cognitive impairment risk, including age, MMSE score, waist-to-height ratio (WHtR), psychological score, activities of daily living (ADL), instrumental abilities of daily living (IADL), and frequency of tooth brushing. The internal and external validation AUCs were 0.8 and 0.74, respectively; and the receiver operating characteristic (ROC) curves indicated good performance ability of the constructed model.

Conclusion

A feasible model to explore the factors influencing cognitive impairment in elderly illiterate women in China and to identify the elders at high risk was successfully constructed.

Diagnostic performance of brief cognitive tests in cognitive impairment screening

INTRODUCTION AND OBJECTIVES

This study aims to assess and compare the diagnostic performance of brief cognitive tests for cognitive impairment (CI) screening recommended by the Spanish guidelines for the integral care of people with Alzheimer's disease and other dementias.

MATERIAL AND METHODS

We performed a phase iii study into the accuracy of diagnostic tests, including patients with suspected CI in a primary care setting. All patients completed the Mini-Mental State Examination (MMSE), the Mini Examen Cognoscitivo (MEC), the Short Portable Mental Status Questionnaire (SPMSQ), the Memory Impairment Screen (MIS), the Clock Drawing Test (CDT), the Eurotest, the Fototest, and the Memory Alteration Test (M@T). CI was diagnosed independently by researchers blinded to scores on these tests. Diagnostic performance was evaluated by calculating the area under the receiver operating characteristic curve (AUC).

RESULTS

The study included 141 individuals (86 with CI). The Eurotest and M@T (AUC ± SE: 0.91 ± 0.02 and 0.90 ± 0.02, respectively) took longer to administer (mean [SD]: 7.1 [1.8] and 6.8 [2.2] min, respectively) and have significantly better diagnostic performance compared to the MMSE, MEC, SPMSQ, and CDT, but not compared to MIS or Fototest (both with an AUC of 0.87 ± 0.03), with the latter taking less than half as long to administer (2.8 [0.8] min). The M@T and MIS only evaluate memory, and the latter cannot be administered to illiterate people.

CONCLUSION

The most advisable tests for CI screening in primary care are the Eurotest, M@T, and Fototest, with the latter being the most efficient as it takes half as long to administer.

Traumatic brain injury in the elderly population: a 20-year experience in a tertiary neurosurgery center in Belgium

PURPOSE

Traumatic brain injury (TBI) rates in the elderly population are rapidly increasing worldwide. However, there are no clinical guidelines for the treatment of elderly TBI to date. This study aims at describing injury patterns and severity, clinical management, and outcomes in elderly TBI patients, which may contribute to specific prognostic tools and clinical guidelines in the future.

METHODS

Clinical records of 2999 TBI patients ≥ 65 years old admitted in the University Hospital Leuven (Belgium) between 1999 and 2019 were manually screened and 1480 cases could be included. Records were scrutinized for relevant clinical data.

RESULTS

The median age in the cohort was 78.0 years (IQR = 12). Falls represented the main accident mechanism (79.7%). The median Glasgow Coma Score on admission was 15 (range 3-15). Subdural hematomas were the most common lesion (28.4%). 90.1% of all patients were hospitalized and 27.0% were admitted to intensive care. 16.4% underwent a neurosurgical intervention. 11.0% of all patients died within 30 days post-TBI. Among the 521 patients with mild TBI, 28.6% were admitted to ICU and 13.1% had a neurosurgical intervention and 30-day mortality was 6.9%.

CONCLUSION

Over the 20-year study period, an increase of age and comorbidities and a reduction in neurosurgical interventions and ICU admissions were observed, along with a trend to less severe injuries but a higher proportion of treatment withdrawals, while at the same time mortality rates decreased. TBI is a life-changing event, leading to severe consequences in the elderly population, especially at higher ages. Even mild TBI is associated with substantial rates of hospitalization, surgery, and mortality in elderly. The characteristics of the elderly population with TBI are subject to changes over time.

The complex burden of determining prevalence rates of mild cognitive impairment: A systematic review

Mild cognitive impairment (MCI) is a syndrome characterized by a decline in cognitive performance greater than expected for an individual's age and education level, but that does not interfere much with daily life activities. Establishing the prevalence of MCI is very important for both clinical and research fields. In fact, in a certain percentage of cases, MCI represents a prodromal condition for the development of dementia. Accordingly, it is important to identify the characteristics of MCI that allow us to predict the development of dementia. Also, initial detection of cognitive decline can allow the early implementation of prevention programs aimed at counteracting or slowing it down. To this end, it is important to have a clear picture of the prevalence of MCI and, consequently, of the diagnostic criteria used. According to these issues, this systematic review aims to analyze MCI prevalence, exploring the methods for diagnosing MCI that determine its prevalence. The review process was conducted according to the PRISMA statement. Three thousand one hundred twenty-one international articles were screened, and sixty-six were retained. In these studies, which involved 157,035 subjects, the prevalence of MCI ranged from 1.2 to 87%. The review results showed a large heterogeneity among studies due to differences in the subjects' recruitment, the diagnostic criteria, the assessed cognitive domains, and other methodological aspects that account for a higher range of MCI prevalence. This large heterogeneity prevents drawing any firm conclusion about the prevalence of MCI.

Cognitive Resilience in Brain Health and Dementia Research

With the expected rise in Alzheimer's disease and related dementias (ADRD) in the coming decades due to the aging population and a lack of effective disease-modifying treatments, there is a need for preventive strategies that may tap into resilience parameters. A wide array of resilience strategies has been proposed including genetics, socioeconomic status, lifestyle modifications, behavioral changes, and management of comorbid disease. These different strategies can be broadly classified as distinguishing between modifiable and non-modifiable risk factors, some of which can be quantified so that their clinical intervention can be effectively accomplished. A clear shift in research focus from dementia risk to addressing disease resistance and resilience is emerging that has provided new potential therapeutic targets. Here we review and summarize the latest investigations of resilience mechanisms and methods of quantifying resilience for clinical research. These approaches include identifying genetic variants that may help identify novel pathways (e.g., lipid metabolism, cellular trafficking, synaptic function, inflammation) for therapeutic treatments and biomarkers for use in a precision medicine-like regimen. In addition, innovative structural and molecular neuroimaging analyses may assist in detecting and quantifying pathological changes well before the onset of clinical symptoms setting up the possibility of primary and secondary prevention trials. Lastly, we summarize recent studies demonstrating the study of resilience in caregivers of persons living with dementia may have direct and indirect impact on the quality of care and patient outcomes.

Prevalence, Incidence, and Progression of Cognitive Impairment, No Dementia Among Rural-Dwelling Chinese Older Adults

BACKGROUND

Few studies have examined occurrence and progression of cognitive impairment, no dementia (CIND) in rural China.

OBJECTIVE

To determine the prevalence and incidence of CIND in rural-dwelling Chinese older adults, and to examine risk and protective factors associated with progression to CIND and dementia.

METHODS

This population-based study included 2,781 dementia-free participants (age≥65 years) who were examined at baseline (2014) and followed in 2018. Demographic, epidemiological, clinical, and neuropsychological data were collected following a structured questionnaire. We defined CIND according to subjective cognitive complaints and the age- and education-specific Mini-Mental State Examination (MMSE) score. Data were analyzed with the multinomial logistic regression models.

RESULTS

The overall prevalence of CIND was 10.54% and the incidence was 28.26 per 1,000 person-years. CIND at baseline was associated with the multi-adjusted odds ratio (OR) of 2.06 (95% confidence interval = 1.23-3.47) for incident dementia. Multinomial logistic regression analysis suggested that compared with no CIND, the multi-adjusted OR of incident CIND was 2.21 (1.51-3.23) for women and 0.62 (0.38-0.99) for high social support, whereas the multi-adjusted OR of incident dementia was 1.14 (1.09-1.18) for older age, 0.29 (0.16-0.53) for high education, and 2.91 (1.47-5.74) for having a stroke history.

CONCLUSION

CIND affects over one-tenth of older adults living in rural communities of western Shandong province. People with CIND are twice as likely to progress to dementia as people without CIND. Female sex, low education, stroke history, and low social support are associated with an increased risk of progression from normal cognition to CIND or dementia.

Incidence of Dementia and Associated Factors in the EPIC-Spain Dementia Cohort

BACKGROUND

Dementia has become a public health priority as the number of cases continues to grow worldwide.

OBJECTIVE

To assess dementia incidence and determinants in the EPIC-Spain Dementia Cohort.

METHODS

25,015 participants (57% women) were recruited from three Spanish regions between 1992-1996 and followed-up for over 20 years. Incident cases were ascertained through individual revision of medical records of potential cases. Crude and age-adjusted incidence rates (IR) of dementia and sub-types (Alzheimer's disease (AD), and non-AD) were calculated by sex. Neelson-Aalen cumulative incidence estimates at 10, 15, and 20 years were obtained for each sex and age group. Multivariate Royston-Parmar models were used to assess independent determinants.

RESULTS

Global IR were higher in women for dementia and AD, and similar by sex for non-AD. IR ranged from 0.09 cases of dementia (95% confidence interval: 0.06-0.13) and 0.05 (0.03-0.09) of AD per 1000 person-years (py) in participants below 60 years, to 23.2 (15.9-33.8) cases of dementia and 14.6 (9.1-33.5) of AD (per 1000 py) in those ≥85 years. Adjusted IR were consistently higher in women than men for overall dementia and AD. Up to 12.5% of women and 9.1% of men 60-65 years-old developed dementia within 20 years. Low education, diabetes, and hyperlipidemia were the main independent predictors of dementia risk, whereas alcohol showed an inverse association.

CONCLUSION

Dementia incidence increased with age and was higher among women, but showed no geographical pattern. Dementia risk was higher among subjects with lower education, not drinking alcohol, and presenting cardiovascular risk factors.

Prevalence of mild cognitive impairment in community-dwelling Chinese populations aged over 55 years: a meta-analysis and systematic review

Background

Mild cognitive impairment (MCI) is an intermediate phase between normal cognitive ageing and overt dementia, with amnesic MCI (aMCI) being the dominant subtype. This study aims to synthesise the prevalence results of MCI and aMCI in community-dwelling populations in China through a meta-analysis and systematic review.

Methods

The study followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) protocol. English and Chinese studies published before 1 March 2020 were searched from ten electronic bibliographic databases. Two reviewers screened for relevance of the studies against the pre-defined inclusion and exclusion criteria and assessed the quality of the included studies using the Risk of Bias Tool independently. A random-effect model was adopted to estimate the prevalence of MCI and aMCI, followed by sub-group analyses and meta-regression. Sensitivity and publication bias tests were performed to verify the robustness of the meta-analyses.

Results

A total of 41 studies with 112,632 participants were included in the meta-analyses. The Chinese community-dwelling populations over 55 years old had a pooled prevalence of 12.2% [95% confidence interval (CI): 10.6, 14.2%] for MCI and 10.9% [95% CI, 7.7, 15.4%] for aMCI, respectively. The prevalence of MCI increased with age. The American Psychiatric Association’s Diagnostic tool (DSM-IV) generated the highest MCI prevalence (13.5%), followed by the Petersen criteria (12.9%), and the National Institute on Aging Alzheimer’s Association (NIA-AA) criteria (10.3%). Women, rural residents, and those who lived alone and had low levels of education had higher MCI prevalence than others.

Conclusion

Higher MCI prevalence was identified in community-dwelling older adult populations in China compared with some other countries, possibly due to more broadened criteria being adopted for confirming the diagnosis. The study shows that aMCI accounts for 66.5% of MCI, which is consistent with findings of studies undertaken elsewhere.

Systematic review registration number

PROSPERO CRD42019134686.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-020-01948-3.

Hospitalization and Socio-Health Care for Dementia in Spain

Dementias are brain diseases that affect long-term cognitive and behavioral functions and cause a decrease in the ability to think and remember that is severe enough to disturb daily functioning. In Spain, the number of people suffering from dementia is rising due to population ageing. Reducing admissions, many of them avoidable, would be advantageous for patients and care-providers. Understanding the correlation of admission of people with dementia and its trends in hospitalization would help us to understand the factors leading to admission. We conducted a cross-sectional study of the hospital discharge database of Castilla y León from 2005 to 2015, selecting hospitalizations for dementia. Trends in hospitalizations by year and age quartiles were studied by joinpoint regression analysis. 2807 out of 2,717,192 total hospitalizations (0.10%) were due to dementias; the main groups were degenerative dementia (1907) followed by vascular dementia (607). Dementias are not a major cause of hospitalization, but the average stay and cost are high, and many of them seem avoidable. Decreasing trends were detected in hospitalization rates for all dementias except for the group of mild cognitive impairment, which grew. An increasing–decreasing joinpoint detected in 2007 for vascular dementia and the general downward hospitalization trends for most dementias suggest that socio-health measures established since 2007 in Spain might play a key role in reducing hospitalizations.

Is it time to use real-world data from primary care in Alzheimer's disease?

BACKGROUND

The analysis of real-world data in clinical research is rising, but its use to study dementia subtypes has been hardly addressed. We hypothesized that real-world data might be a powerful tool to update AD epidemiology at a lower cost than face-to-face studies, to estimate the prevalence and incidence rates of AD in Catalonia (Southern Europe), and to assess the adequacy of real-world data routinely collected in primary care settings for epidemiological research on AD.

METHODS

We obtained data from the System for the Development of Research in Primary Care (SIDIAP) database, which contains anonymized information of > 80% of the Catalan population. We estimated crude and standardized incidence rates and prevalences (95% confidence intervals (CI)) of AD in people aged at least 65 years living in Catalonia in 2016.

RESULTS

Age- and sex-standardized prevalence and incidence rate of AD were 3.1% (95%CI 2.7-3.6) and 4.2 per 1000 person-years (95%CI 3.8-4.6), respectively. Prevalence and incidence were higher in women and in the oldest people.

CONCLUSIONS

Our incidence and prevalence estimations were slightly lower than the recent face-to-face studies conducted in Spain and higher than other analyses of electronic health data from other European populations. Real-world data routinely collected in primary care settings could be a powerful tool to study the epidemiology of AD.

[DIABDEM project: A pilot study of prevalence of cognitive impairment in diabetes mellitus in 2 Hispanic countries]

INTRODUCTION

The prevalence of chronic noncommunicable diseases such as type 2 diabetes mellitus (T2DM) and dementia increase with ageing. In this context, an association between T2DM and cognitive impairment has been described in the literature. However, there are few studies in the Hispanic population. This research project presents a pilot study that will evaluate the feasibility of the DIABDEM project that will determine the prevalence of cognitive impairment in old people with diagnosis of T2DM in Spain and Chile.

MATERIALS AND METHODS

It is a observation-based pilot study, non-experimental, descriptive-comparative and cross-sectional. The sample will involve 72 participants (39 Spaniards and 33 Chileans), 65 year-old or older, men and women, community dwelling, and who have not been previously diagnosed with dementia, with or without a T2DM diagnosis. Participants will fill in a research protocol form collecting socio-demographic and clinical data, lifestyle details, and neuropsychological variables.

EXPECTED RESULTS

This study will evaluate the feasibility of the DIABDEM project that will determine the prevalence rate of cognitive impairment in old people with T2DM. On one hand, the aim of this study will establish risk and protectors factors potentially associated with the development of cognitive impairment in T2DM. On the other hand, it is expected to identify a specific neuropsychological profile in people with T2DM, proposing later a brief and useful neuropsychological battery in order to discriminate early cognitive impairment in people with T2DM.

CONCLUSION

Findings in this pilot study will obtain greater knowledge about the feasibility of the DIABDEM project, which will provide evidence about cognitive complications in T2DM.

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.

Cognitive Assessment Tools for Screening Older Adults With Low Levels of Education: A Critical Review

Introduction: Cognitive assessment of older adults who are either illiterate or with low levels of education is particularly challenging because several battery tasks require a certain educational background. Early detection of mild cognitive impairment (MCI) in the elderly using validated screening tools is of great importance since this population group could benefit from new drugs that are being investigated for the treatment of dementias. Cutoff scores for psychometric properties of cognitive tests are not well established among adults with low levels of education. The present study aimed to critically review the literature on cognitive assessment tools for screening cognitive syndromes including MCI and Alzheimer's disease (AD) in older adults with low levels of education. Methods: We conducted a systematic search of MEDLINE, LILACS, Cochrane, and SCOPUS electronic databases of cross-sectional and prospective studies with adults over 55 years of age. Results: We found a significant number of assessment tools available (n = 44), but only a few of them showed diagnostic accuracy for the diagnosis of MCI and AD in older adults with low levels of education: the Mini-Mental State Exam; the Montreal Cognitive Assessment; the Persian Test of Elderly for Assessment of Cognition and Executive Function; the Six-Item Screener; and the Memory Alteration Test. Few studies evaluated individuals with low levels of education, with a wide range of cutoff scores and cognitive test batteries. Conclusion: We found that a small number of studies evaluated adults with 4 years of formal education or less. Our findings further support the importance of developing specific tools for the assessment of older adults with low levels of education.

Prevalence of and Risk Factors for Cognitive Impairment Among Elderly Without Cardio- and Cerebrovascular Diseases: A Population-Based Study in Rural China

This study aimed to evaluate the prevalence of cognitive impairment and the distribution of its risk factors among residents aged ≥60 years without cardiovascular and cerebrovascular diseases in rural areas of northern China screened with the Chinese version of the Mini-Mental State Examination (MMSE). Between 2012 and 2013, a questionnaire survey was conducted to collect basic information from participants. Cognitive function was assessed using the MMSE. In the univariate analysis, risk factors for cognitive disorders were female sex, low education and central obesity, while drinking was found to be a protective factor. In the multivariate analysis, risk factors were old age (odds ratio [OR], 1.888; 95% confidence interval [CI]: 1.256–2.838; P = 0.002 for the 70-year-old group compared with the 60-year-old group; OR, 3.593; 95% CI, 2.468–5.230; P < 0.001 for the ≥75-year-old group compared with the 60-year-old group), low education (OR, 3.779; 95% CI: 2.218–6.440; P < 0.001 for the illiterate group compared with the group with ≥9 years of education; OR, 1.667; 95% CI, 1.001–2.775; P = 0.05 for the group with less than primary school compared with the group with ≥9 years of education), and higher blood pressure (BP; OR, 1.655; 95% CI: 1.076–2.544; P = 0.002 for individuals with stage III hypertension compared with those with normal BP). These findings suggest that it is crucial to manage and control level of BP, and improve educational attainment in order to reduce the prevalence and burden of cognitive impairment among low-income residents in rural China.

A Systematic Review and Meta-Analysis on the Prevalence of Dementia in Europe: Estimates from the Highest-Quality Studies Adopting the DSM IV Diagnostic Criteria

BACKGROUND

Dementia, including Alzheimer's disease (AD), is one of the most burdensome medical conditions. Usually, the reviews that aim at calculating the prevalence of dementia include estimates from studies without assessing their methodological quality. Alzheimer's Disease International (ADI) proposed a score to assess the methodological quality of population-based studies aimed at estimating the prevalence of dementia. During the last three years, the European Commission has funded three projects (Eurodem, EuroCoDe, and ALCOVE) in order to estimate the prevalence of dementia in Europe.

OBJECTIVE

The aim of this study was to perform a systematic review and meta-analysis of data on the prevalence of dementia in Europe derived from studies that included only subjects with a diagnosis of dementia according to the DSM IV criteria, and that had a high quality score according to ADI criteria.

METHODS

We considered the studies selected by the two projects EuroCoDe (1993-2007) and Alcove (2008-2011), and we performed a new bibliographic search. For the systematic review, we only selected the subset of articles that included subjects with a diagnosis of dementia according to the DSM IV criteria. The studies were qualitatively assessed using the ADI tool.

RESULTS

The meta-analysis considered 9 studies that were carried out in Europe between 1993 and 2018 including a total of 18,263 participants, of which 2,137 were diagnosed with dementia. The prevalence rate standardized for age and sex resulted 7.1%.

DISCUSSION

This is the first systematic review on the prevalence of dementia in Europe considering only high-quality studies adopting the same diagnostic criteria (i.e., DSM IV).

Practice guideline update summary: Mild cognitive impairment: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology

OBJECTIVE

To update the 2001 American Academy of Neurology (AAN) guideline on mild cognitive impairment (MCI).

METHODS

The guideline panel systematically reviewed MCI prevalence, prognosis, and treatment articles according to AAN evidence classification criteria, and based recommendations on evidence and modified Delphi consensus.

RESULTS

MCI prevalence was 6.7% for ages 60-64, 8.4% for 65-69, 10.1% for 70-74, 14.8% for 75-79, and 25.2% for 80-84. Cumulative dementia incidence was 14.9% in individuals with MCI older than age 65 years followed for 2 years. No high-quality evidence exists to support pharmacologic treatments for MCI. In patients with MCI, exercise training (6 months) is likely to improve cognitive measures and cognitive training may improve cognitive measures.

MAJOR RECOMMENDATIONS

Clinicians should assess for MCI with validated tools in appropriate scenarios (Level B). Clinicians should evaluate patients with MCI for modifiable risk factors, assess for functional impairment, and assess for and treat behavioral/neuropsychiatric symptoms (Level B). Clinicians should monitor cognitive status of patients with MCI over time (Level B). Cognitively impairing medications should be discontinued where possible and behavioral symptoms treated (Level B). Clinicians may choose not to offer cholinesterase inhibitors (Level B); if offering, they must first discuss lack of evidence (Level A). Clinicians should recommend regular exercise (Level B). Clinicians may recommend cognitive training (Level C). Clinicians should discuss diagnosis, prognosis, long-term planning, and the lack of effective medicine options (Level B), and may discuss biomarker research with patients with MCI and families (Level C).

Report by the Spanish Foundation of the Brain on the social impact of Alzheimer disease and other types of dementia

INTRODUCTION

Knowledge of the socioeconomic impact of dementia-related disorders is essential for appropriate management of healthcare resources and for raising social awareness.

METHODS

We performed a literature review of the published evidence on the epidemiology, morbidity, mortality, associated disability and dependence, and economic impact of dementia and Alzheimer disease (AD) in Spain.

CONCLUSIONS

Most population studies of patients older than 65 report prevalence rates ranging from 4% to 9%. Prevalence of dementia and AD is higher in women for nearly every age group. AD is the most common cause of dementia (50%-70% of all cases). Dementia is associated with increased morbidity, mortality, disability, and dependence, and results in a considerable decrease in quality of life and survival. Around 80% of all patients with dementia are cared for by their families, which cover a mean of 87% of the total economic cost, resulting in considerable economic and health burden on caregivers and loss of quality of life. The economic impact of dementia is huge and difficult to evaluate due to the combination of direct and indirect costs. More comprehensive programmes should be developed and resources dedicated to research, prevention, early diagnosis, multidimensional treatment, and multidisciplinary management of these patients in order to reduce the health, social, and economic burden of dementia.

Prevalence of mild cognitive impairment and its subtypes in community-dwelling residents aged 65 years or older in Guangzhou, China

BACKGROUND

Prevalence of mild cognitive impairment (MCI) has been reported substantial variations, and mostly in Western countries. Less is known about MCI in the south of China. The study is to estimate the prevalence of MCI and its subtypes in residents aged 65year or older in community-dwelling residents of Guangzhou, China.

METHODS

The study was a community-based, cross-sectional study conducted in rural and urban areas of Guangzhou between April and October 2009. Eight communities were randomly selected using a cluster sampling method. Each elderly was interviewed with Montreal Cognitive Assessment, the Mini-Mental state examination, Auditory Verbal Learning Test, the Clinical Dementia Rating scale et al. MCI was classified as amnestic MCI (a-MCI) or nonamnestic MCI (na-MCI).

RESULTS

2427 individuals were contacted, but in-person interviews were conducted with 2111 participants. 299 participants with MCI were identified. The prevalence of MCI, a-MCI and na-MCI was 14.2%, 12.2%, 2.0% respectively. The prevalence of MCI and a-MCI increased with age, decreased with education level, and was higher in rural areas than in urban areas. The difference of prevalence of MCI and a-MCI between women with men wasn't statistically significant(MCIχ2=1.0, OR 0.9, 95%CI=0.6-1.2; a-MCIχ2=1.0, OR 0.9, 95%CI=0.6-1.2), when controlling for education by logistic regression analysis.

CONCLUSIONS

The results suggest that 14.2% of elderly individuals are affected by MCI in Guangzhou, China. And MCI was dominated by a-MCI. The prevalence of MCI and a-MCI increased with age, decreased with education level, and was higher in the rural population compared to the urban population.

Cognitive impairment and hypertension in older adults living in extreme poverty: a cross-sectional study in Peru

BACKGROUND

Previous studies have shown that hypertension is a risk factor for cognitive impairment, but whether this association is also present in extremely poor populations in Low Middle Income Countries settings remains to be studied. Understanding other drivers of cognitive impairment in this unique population also merits attention.

METHODS

We performed a secondary analysis using data from the "Encuesta de Salud y Bienestar del Adulto Mayor", a regional survey conducted in an extremely poor population of people older than 65 years old from 12 Peruvian cities in 2012. The outcome variable was cognitive impairment, determined by a score of ≤7 in the modified Mini-Mental State Examination. The exposure was self-reported hypertension status. Variables such as age, gender, controlled hypertension, education level, occupation, depression and area of living (rural/urban) were included in the adjusted analysis. We used Poisson regression with robust variance to calculate prevalence ratios (PR) and 95% confidence interval (95% CI) adjusting for confounders.

RESULTS

Data from 3842 participants was analyzed, 51.8% were older than 70 years, and 45.6% were females. The prevalence of cognitive impairment was 1.7% (95% CI 1.3%-2.1%). There was no significant difference on the prevalence of cognitive impairment between the group of individuals with hypertension in comparison with those without hypertension (PR = 0.64, 95% CI 0.33-1.23).

CONCLUSIONS

The association described between hypertension and cognitive impairment was not found in a sample of extremely poor Peruvian older adults.

Cognitive functioning among Dutch older adults: Do neighborhood socioeconomic status and urbanity matter?

Positive associations of neighborhood socioeconomic characteristics and older adults' cognitive functioning have been demonstrated in previous studies, but overall results have been mixed and evidence from European countries and particularly the Netherlands is scarce. We investigated the effects of socioeconomic status (SES) and urbanity of neighborhoods on four domains of cognitive functioning in a sample of 985 Dutch older adults aged 65-88 years from the Longitudinal Aging Study Amsterdam. Besides cross-sectional level differences in general cognitive functioning, processing speed, problem solving and memory, we examined cognitive decline over a period of six years. Growth models in a multilevel framework were used to simultaneously assess levels and decline of cognitive functioning. In models not adjusting for individual SES, we found some evidence of higher levels of cognitive functioning in neighborhoods with a higher SES. In the same models, urbanity generally showed positive or inversely U-shaped associations with levels of cognitive functioning. Overall, effects of neighborhood urbanity remained significant when adjusting for individual SES. In contrast, level differences by neighborhood SES were largely explained by the respondents' individual SES. This suggests that neighborhood SES does not influence levels of cognitive functioning beyond the fact that individuals with a similar SES tend to self-select into neighborhoods with a corresponding SES. No evidence of systematically faster decline in neighborhoods with lower SES or lower degrees of urbanity was found. The findings suggest that neighborhood SES has no independent effect on older adults cognitive functioning in the Netherlands. Furthermore, the study reveals that neighborhood urbanity should be considered a determinant of cognitive functioning. This finding is in line with theoretical approaches that assume beneficial effects of exposure to complex environments on cognitive functioning. We encourage further investigations into the effect of urbanity in other contexts before drawing firm conclusions.

Sex differences in the prevalence and incidence of mild cognitive impairment: A meta-analysis

OBJECTIVE

More women have Alzheimer's disease (AD) than men. Understanding sex differences in mild cognitive impairment (MCI) may further knowledge of AD etiology and prevention. We conducted a meta-analysis to examine sex differences in the prevalence and incidence of MCI, which included amnestic and non-amnestic subtypes.

METHOD

Systematic searches were performed in July 2015 using MEDLINE/PubMed, Scopus, and PsycINFO for population-or community-based studies with MCI data for men and women. Random-effects model were used.

RESULTS

Fifty-six studies were included. There were no statistically significant sex differences in prevalence or incidence of amnestic MCI. There was a significantly higher prevalence (p=0.038), but not incidence, of non-amnestic MCI among women. There were no sex differences in studies that combined both subtypes of MCI.

CONCLUSION

The only statistically significant finding emerging from this study was that women have a higher prevalence of non-amnestic MCI. To better understand sex differences in the preclinical stages of dementia, studies must better characterize the etiology of the cognitive impairment.

The Prevalence and Incidence of Dementia Due to Alzheimer's Disease: a Systematic Review and Meta-Analysis

BACKGROUND

Updated information on the epidemiology of dementia due to Alzheimer's disease (AD) is needed to ensure that adequate resources are available to meet current and future healthcare needs. We conducted a systematic review and meta-analysis of the incidence and prevalence of AD.

METHODS

The MEDLINE and EMBASE databases were searched from 1985 to 2012, as well as the reference lists of selected articles. Included articles had to provide an original population-based estimate for the incidence and/or prevalence of AD. Two individuals independently performed abstract and full-text reviews, data extraction and quality assessments. Random-effects models were employed to generate pooled estimates stratified by age, sex, diagnostic criteria, location (i.e., continent) and time (i.e., when the study was done).

RESULTS

Of 16,066 abstracts screened, 707 articles were selected for full-text review. A total of 119 studies met the inclusion criteria. In community settings, the overall point prevalence of dementia due to AD among individuals 60+ was 40.2 per 1000 persons (CI95%: 29.1-55.6), and pooled annual period prevalence was 30.4 per 1000 persons (CI95%: 15.6-59.1). In community settings, the overall pooled annual incidence proportion of dementia due to AD among individuals 60+ was 34.1 per 1000 persons (CI95%: 16.4-70.9), and the incidence rate was 15.8 per 1000 person-years (CI95%: 12.9-19.4). Estimates varied significantly with age, diagnostic criteria used and location (i.e., continent).

CONCLUSIONS

The burden of AD dementia is substantial. Significant gaps in our understanding of its epidemiology were identified, even in a high-income country such as Canada. Future studies should assess the impact of using such newer clinical diagnostic criteria for AD dementia such as those of the National Institute on Aging-Alzheimer's Association and/or incorporate validated biomarkers to confirm the presence of Alzheimer pathology to produce more precise estimates of the global burden of AD.

Prevalence of cognitive impairment in Spain: The Gómez de Caso study in health sentinel networks

INTRODUCTION

Cognitive impairment, a clinical entity causing complete or partial intellectual dysfunction, is a major public health concern that poses a challenge for health and social services. The purpose of this study is to estimate the prevalence of this disorder in people aged 65 and older visiting the primary care physician in 5 health sentinel networks.

METHOD

A sample of patients visiting their primary care doctor on 4 randomly selected days completed the Mini-Cog screening test. Diagnosis of cognitive impairment was confirmed with the Mini-Mental State Examination and the Alzheimer's Questionnaire. We estimated raw and adjusted rates using demographic and social variables.

RESULTS

We included 4,624 patients from 5 autonomous communities and representing a population of 1,723,216 inhabitants. The adjusted prevalence rate was 18.5% (95% CI 17.3-19.7], with differences between sentinel networks. Women showed higher adjusted rates than men: 18.5 vs. 14.3%. The highest prevalence rate was observed in people aged 85 and older (45.3%); prevalence rates vary depending on education level and marital status.

CONCLUSIONS

Cognitive impairment is a frequent reason for consultations in primary care. Its prevalence is higher in women and increases exponentially with age. A number of sensitive, validated tools have been proven useful in screening for and confirming cognitive impairment. Using these tools in primary care settings enables early treatment of these patients.

Age-Stratified Prevalence of Mild Cognitive Impairment and Dementia in European Populations: A Systematic Review

The prevalence of mild cognitive impairment (MCI) and dementia according to age remain uncertain. We systematically extracted age-stratified estimates of MCI and dementia prevalence reported in European studies published since 1995, and performed meta-analyses for dementia. We identified 10 relevant studies on MCI and 26 studies on dementia. Studies on MCI presented substantial heterogeneity preventing a meta-analysis, with a majority reporting an increase in prevalence at ≥75 years old. Pooled prevalence of dementia rose continuously from 55 years of age, reaching 44.7% (39.8; 49.6) in those ≥95 years of age. Homogenization of MCI criteria, and additional studies in Northern European population would be warranted.

The Prevalence and Incidence of Dementia: a Systematic Review and Meta-analysis

Introduction

Dementia is a common neurological condition affecting many older individuals that leads to a loss of independence, diminished quality of life, premature mortality, caregiver burden and high levels of healthcare utilization and cost. This is an updated systematic review and meta-analysis of the worldwide prevalence and incidence of dementia.

Methods

The MEDLINE and EMBASE databases were searched for relevant studies published between 2000 (1985 for Canadian papers) and July of 2012. Papers selected for full-text review were included in the systematic review if they provided an original population-based estimate for the incidence and/or prevalence of dementia. The reference lists of included articles were also searched for additional studies. Two individuals independently performed abstract and full-text review, data extraction, and quality assessment of the papers. Random-effects models and/or meta-regression were used to generate pooled estimates by age, sex, setting (i.e., community, institution, both), diagnostic criteria utilized, location (i.e., continent) and year of data collection.

Results

Of 16,066 abstracts screened, 707 articles were selected for full-text review. A total of 160 studies met the inclusion criteria. Among individuals 60 and over residing in the community, the pooled point and annual period prevalence estimates of dementia were 48.62 (CI95%: 41.98-56.32) and 69.07 (CI95%: 52.36-91.11) per 1000 persons, respectively. The respective pooled incidence rate (same age and setting) was 17.18 (CI95%: 13.90-21.23) per 1000 person-years, while the annual incidence proportion was 52.85 (CI95%: 33.08-84.42) per 1,000 persons. Increasing participant age was associated with a higher dementia prevalence and incidence. Annual period prevalence was higher in North America than in South America, Europe and Asia (in order of decreasing period prevalence) and higher in institutional compared to community and combined settings. Sex, diagnostic criteria (except for incidence proportion) and year of data collection were not associated with statistically significant different estimates of prevalence or incidence, though estimates were consistently higher for females than males.

Conclusions

Dementia is a common neurological condition in older individuals. Significant gaps in knowledge about its epidemiology were identified, particularly with regard to the incidence of dementia in low- and middle-income countries. Accurate estimates of prevalence and incidence of dementia are needed to plan for the health and social services that will be required to deal with an aging population.

Environment as 'Brain Training': A review of geographical and physical environmental influences on cognitive ageing

Global ageing demographics coupled with increased urbanisation pose major challenges to the provision of optimal living environments for older persons, particularly in relation to cognitive health. Although animal studies emphasize the benefits of enriched environments for cognition, and brain training interventions have shown that maintaining or improving cognitive vitality in older age is possible, our knowledge of the characteristics of our physical environment which are protective for cognitive ageing is lacking. The present review analyses different environmental characteristics (e.g. urban vs. rural settings, presence of green) in relation to cognitive performance in ageing. Studies of direct and indirect associations between physical environment and cognitive performance are reviewed in order to describe the evidence that our living contexts constitute a measurable factor in determining cognitive ageing.

Findings on Advance Care Plans among Cognitively Impaired Older Adults

Cognitively impaired and cognitively intact older adults seemingly differ regarding engagement in aspects of advance care plans (ACPs). Through informant reports in the Canadian Study on Health and Aging, we examined differences between deceased cognitively impaired and intact older adults in components of ACPs: (1) discussions/arrangements for end-of-life care; (2) creation of legal documents; and in ACP outcomes, (3) location of death; and (4) dying in accordance with wishes. Cognitively impaired older adults were more likely to have made arrangements for a substitute decision-maker (OR = 1.90) and to have created legal documents (OR = 2.64 for health care preferences, OR = 2.00 for naming a decision-maker). They were less likely to have discussed preferences for end-of-life care (OR = 0.62). These findings suggest that ACPs differ for cognitively impaired persons, indicating a need for further investigation. This is a step towards understanding this complex process in a particularly vulnerable population.

Serum folate, vitamin B12 and cognitive impairment in Chilean older adults

OBJECTIVE

To analyse the relationship between serum folate (SF), vitamin B12 and impaired cognitive function in the Chilean elderly.

DESIGN

We analysed the relationships between impaired cognitive function and age, SF (µg/l) and vitamin B12 (pg/ml) with Student's t test, as well as between impaired cognitive function and gender, educational level, residence area, diabetes and hypertension with the χ 2 test. Multiple logistic regressions with interactions were estimated to assess the impact of SF on impaired cognitive function according to these methods.

SETTING

Chile.

SUBJECTS

Older adults (>65 years, n 1051), drawn from representative households of a national prevalence study, assessed using the Modified Mini Mental Status Examination (MMMSE). Individuals with altered MMMSE scores (≤13 points) were sequentially assessed using the Pfeffer Functional Activities Questionnaire (PFAQ).

RESULTS

Multivariate models using the MMMSE demonstrated an increased risk of impaired cognitive function for seniors who had hypertension, diabetes and higher vitamin B12 levels. SF and its square (SF2) were statistically significant, indicating that this predictor of impaired cognitive function displays a U-shaped distribution. The interaction between SF and vitamin B12 was not statistically significant. Models using the MMMSE plus PFAQ suggested that urban residence decreased the risk of impaired cognitive function, whereas male gender, older age, vitamin B12 levels and hypertension increased this risk. The variables SF and SF2 and the SF × vitamin B12 interaction were statistically significant (P<0.05). The risk of impaired cognitive function depended on different combinations of SF and vitamin B12 levels. When SF was low, a one-unit increase in SF (1 µg/l) diminished the risk. When SF was elevated, a further increase in SF raised the risk, especially at low vitamin B12 levels.

CONCLUSIONS

The relationship between folate, vitamin B12 and impaired cognitive function warrants further study.

Epidemiologic studies of modifiable factors associated with cognition and dementia: systematic review and meta-analysis

Background

Cognitive impairment, including dementia, is a major health concern with the increasing aging population. Preventive measures to delay cognitive decline are of utmost importance. Alzheimer’s disease (AD) is the most frequent cause of dementia, increasing in prevalence from <1% below the age of 60 years to >40% above 85 years of age.

Methods

We systematically reviewed selected modifiable factors such as education, smoking, alcohol, physical activity, caffeine, antioxidants, homocysteine (Hcy), n-3 fatty acids that were studied in relation to various cognitive health outcomes, including incident AD. We searched MEDLINE for published literature (January 1990 through October 2012), including cross-sectional and cohort studies (sample sizes > 300). Analyses compared study finding consistency across factors, study designs and study-level characteristics. Selecting studies of incident AD, our meta-analysis estimated pooled risk ratios (RR), population attributable risk percent (PAR%) and assessed publication bias.

Results

In total, 247 studies were retrieved for systematic review. Consistency analysis for each risk factor suggested positive findings ranging from ~38.9% for caffeine to ~89% for physical activity. Education also had a significantly higher propensity for “a positive finding” compared to caffeine, smoking and antioxidant-related studies. Meta-analysis of 31 studies with incident AD yielded pooled RR for low education (RR = 1.99; 95% CI: 1.30-3.04), high Hcy (RR = 1.93; 95% CI: 1.50-2.49), and current/ever smoking status (RR = 1.37; 95% CI: 1.23-1.52) while indicating protective effects of higher physical activity and n-3 fatty acids. Estimated PAR% were particularly high for physical activity (PAR% = 31.9; 95% CI: 22.7-41.2) and smoking (PAR%=31.09%; 95% CI: 17.9-44.3). Overall, no significant publication bias was found.

Conclusions

Higher Hcy levels, lower educational attainment, and decreased physical activity were particularly strong predictors of incident AD. Further studies are needed to support other potential modifiable protective factors, such as caffeine.

Motor phenotype of decline in cognitive performance among community-dwellers without dementia: population-based study and meta-analysis

Background

Decline in cognitive performance is associated with gait deterioration. Our objectives were: 1) to determine, from an original study in older community-dwellers without diagnosis of dementia, which gait parameters, among slower gait speed, higher stride time variability (STV) and Timed Up & Go test (TUG) delta time, were most strongly associated with lower performance in two cognitive domains (i.e., episodic memory and executive function); and 2) to quantitatively synthesize, with a systematic review and meta-analysis, the association between gait performance and cognitive decline (i.e., mild cognitive impairment (MCI) and dementia).

Methods

Based on a cross-sectional design, 934 older community-dwellers without dementia (mean±standard deviation, 70.3±4.9years; 52.1% female) were recruited. A score at 5 on the Short Mini-Mental State Examination defined low episodic memory performance. Low executive performance was defined by clock-drawing test errors. STV and gait speed were measured using GAITRite system. TUG delta time was calculated as the difference between the times needed to perform and to imagine the TUG. Then, a systematic Medline search was conducted in November 2013 using the Medical Subject Heading terms “Delirium,” “Dementia,” “Amnestic,” “Cognitive disorders” combined with “Gait” OR “Gait disorders, Neurologic” and “Variability.”

Findings

A total of 294 (31.5%) participants presented decline in cognitive performance. Higher STV, higher TUG delta time, and slower gait speed were associated with decline in episodic memory and executive performances (all P-values <0.001). The highest magnitude of association was found for higher STV (effect size  =  −0.74 [95% Confidence Interval (CI): −1.05;−0.43], among participants combining of decline in episodic memory and in executive performances). Meta-analysis underscored that higher STV represented a gait biomarker in patients with MCI (effect size  =  0.48 [95% CI: 0.30;0.65]) and dementia (effect size  = 1.06 [95% CI: 0.40;1.72]).

Conclusion

Higher STV appears to be a motor phenotype of cognitive decline.

Prevalence and clinical predictors of cognitive impairment in individuals aged 80 years and older in rural China

AIMS

The aim of this study was to estimate the prevalence of cognitive impairment (CI) in individuals aged 80 years and over in rural China and to analyze the associated risk factors.

METHODS

We conducted a two-phase door-to-door survey of a population in rural Ji County (China). The reference population consisted of individuals aged 80 years or older. A total of 723 individuals were interviewed in their homes, and demographic variables and comorbidities were recorded. Diagnoses were divided into the following 3 categories: normal cognitive function, cognitive impairment no dementia (CIND), and dementia. The odds ratio for each risk factor was calculated by logistic regression analysis.

RESULTS

The prevalence of CI among individuals aged 80 years and older was 73.2% (47.4% CIND and 25.7% dementia). The risk of CI decreased with a higher level of education and a higher level of social involvement. The risk of CI was higher in females than in males and among people with a history of stroke (p < 0.01).

CONCLUSIONS

The observed raw prevalence of CI was 73.2%. Female gender and a history of a previous stroke increased the risk of CI, while a higher educational level and engagement in social activities reduced the risk of CI.

Prevalence of cognitive impairment no dementia in a rural area of Northern China

OBJECTIVE

Few data are available on the prevalence of cognitive impairment no dementia (CIND) in rural China. The aim of this study was to estimate the prevalence of CIND in individuals aged 60 years and older in a large rural community, and to analyze the associated risk factors.

METHODS

A two-phase, door-to-door epidemiological study was used for residents aged 60 years and older in Ji County, a rural county near Tianjin in Northern China. In phase 1 of the study, the Mini-Mental State Examination and Clinical Dementia Rating were administered for screening purposes. In phase 2, the subjects who screened positive were further examined by neurologists. A total of 5,744 individuals underwent the home visit interview, where demographic variables and comorbidities were recorded; 5,550 individuals completed the two phases. CIND was diagnosed by the Aging, Demographics and Memory Study on CIND criteria. The odds ratio (OR) for each risk factor was calculated by logistic regression analysis.

RESULTS

The prevalence of CIND among those aged 60 years and older was 23.3%. The prevalence of CIND was lower among those with a higher level of education or social involvement. CIND was more prevalent in females, older individuals, those with a past history of stroke, and those living without a partner. Significant risk factors were found by multivariate analyses: past history of stroke (OR = 1.889; 95% CI: 1.437-2.483); being female (OR = 1.546; 95% CI: 1.305-1.832); and having no partner (divorced, widowed or single; OR = 1.250; 95% CI: 1.042-1.499). In turn, level of education (OR = 0.560; 95% CI: 0.460-0.681) and engagement in social activities (OR = 0.339; 95% CI: 0.258-0.404) were protective factors.

CONCLUSIONS

This is the first large-scale community-based epidemiological study assessing the prevalence of cognitive loss in the rural Chinese population. The total prevalence of CIND observed was 23.3%, which was higher than in other studies in Western and Asian countries. Living without a partner, female gender and previous stroke increased the risk of CIND, whereas a higher level of education and engagement in social activities reduced the risk of CIND.

Accessibility and use of urban green spaces, and cardiovascular health: findings from a Kaunas cohort study

BACKGROUND

The aims of this study were to explore associations of the distance and use of urban green spaces with the prevalence of cardiovascular diseases (CVD) and its risk factors, and to evaluate the impact of the accessibility and use of green spaces on the incidence of CVD among the population of Kaunas city (Lithuania).

METHODS

We present the results from a Kaunas cohort study on the access to and use of green spaces, the association with cardiovascular risk factors and other health-related variables, and the risk of cardiovascular mortality and morbidity. A random sample of 5,112 individuals aged 45-72 years was screened in 2006-2008. During the mean 4.41 years follow-up, there were 83 deaths from CVD and 364 non-fatal cases of CVD among persons free from CHD and stroke at the baseline survey. Multivariate Cox proportional hazards regression models were used for data analysis.

RESULTS

We found that the distance from people's residence to green spaces was not related to the prevalence of health-related variables. However, the prevalence of cardiovascular risk factors and the prevalence of diabetes mellitus were significantly lower among park users than among non-users. During the follow up, an increased risk of non-fatal and fatal CVD combined was observed for those who lived ≥629.61 m from green spaces (3rd tertile of distance to green space) (hazard ratio (HR) = 1.36), and the risk for non-fatal CVD-for those who lived ≥347.81 m (2nd and 3rd tertile) and were not park users (HR = 1.66) as compared to men and women who lived 347.8 m or less (1st tertile) from green space. Men living further away from parks (3rd tertile) had a higher risk of non-fatal and fatal CVD combined, compared to those living nearby (1st tertile) (HR = 1.51). Compared to park users living nearby (1st tertile), a statistically significantly increased risk of non-fatal CVD was observed for women who were not park users and living farther away from parks (2nd and 3rd tertile) (HR = 2.78).

CONCLUSION

Our analysis suggests public health policies aimed at promoting healthy lifestyles in urban settings could produce cardiovascular benefits.

European studies on the prevalence of dementia in the elderly: time for a step towards a methodological consensus

OBJECTIVE

The aim of this study was to discuss methodological limitations in studies on the prevalence of dementia across European countries with particular attention to post-EURODEM studies.

METHODS

Two people independently focused on an iterative literature search for studies published in the years 2000-2012 using the following keywords: 'dementia', 'Alzheimer', 'incidence', 'prevalence' that were cross-linked with names of European countries. After that, the results obtained were compared and publications in English were included in a subsequent analysis.

RESULTS

We included 26 studies published in the years 2000-2012. The majority of epidemiological studies come from Spain and Italy. The past decade has not provided prevalence rates from a considerable number of countries. There is also a lack of nationwide surveys on the prevalence of dementia. Predominantly, epidemiological studies on the prevalence of dementia follow a two-stage approach that consists of a screening phase and a subsequent confirmation of dementia. However, several differences, particularly with regard to the neuropsychological instruments used, still exist and contribute to inconsistent prevalence rates.

CONCLUSIONS

Although the EURODEM study was a milestone in the epidemiology of dementia in Europe and provided several future directions for research, methodological limitations are apparent in a number of European studies on the prevalence of dementia and require particular attention. In particular, a variety of diagnostic instruments requires unification for future studies. On the other hand, given the lack of epidemiological studies from a number of countries and the increasing prevalence of dementia, the need for population-based surveys should be emphasized.

Prevalence and correlates of mild cognitive impairment in adults aged over 50 years with subjective cognitive complaints in primary care centers

AIM

To examine the prevalence and correlates of mild cognitive impairment in adults aged over 50 years attending primary care centers with complaints of cognitive failure.

METHODS

A sample of 689 individuals aged ≥ 50 years with no previous diagnosis of dementia was assessed by use of the Mini-Mental State Examination, the Cambridge Cognitive Examination-Revised and the California Verbal Learning Test--to evaluate the mild cognitive impairment as dependent variables--and administration of a questionnaire on cognitive complaints and other instruments--to measure correlates.

RESULTS

The prevalence of mild cognitive impairment was 31.40%, and positive associations were found for age, occupation, subjective memory complaints, reading habits and level of vocabulary. In the logistic regression, modeled mild cognitive impairment was associated with age (70 years or older), subjective cognitive complaints and level of vocabulary.

CONCLUSION

Almost one-third of the adults aged ≥ 50 years attending primary care centers with subjective cognitive complaints were affected by mild cognitive impairment. Early evaluation of cognitive functioning is essential to establish adequate preventive and intervention strategies.

Prevalence of dementia and subtypes in Valladolid, northwestern Spain: the DEMINVALL study

OBJECTIVE

To describe the prevalence of dementia and subtypes in a general elderly population in northwestern Spain and to analyze the influence of socio-demographic factors.

METHODS

Cross-sectional, two-phase, door-to-door, population-based study. A total of 870 individuals from a rural region and 2,119 individuals from an urban region of Valladolid, Spain, were involved. The seven-minute screen neurocognitive battery was used in the screening phase. A control group was included.

RESULTS

A total of 2,170 individuals aged 65 to 104 years (57% women) were assessed. There were 184 subjects diagnosed with dementia. The crude prevalence was 8.5% (95% CI: 7.3-9.7). Age- and sex-adjusted prevalence was 5.5 (95% CI: 4.5-6.5). Main subtypes of dementia were: Alzheimer's disease (AD) 77.7%, Lewy Body disease, 7.6% and vascular dementia (VD) 5.9%. Crude prevalences were 6.6% (AD), 0.6% (Lewy Body disease), and 0.5% (VD). Dementia was associated with age (OR 1.14 for 1-year increase in age), female sex (OR 1.79) and the absence of formal education (OR 2.53 compared to subjects with primary education or more).

CONCLUSION

The prevalence of dementia in the study population was lower than the most recent estimates for Western Europe. There was a high proportion of AD among all dementia cases and very low prevalence of VD. Old age, female sex, and low education level were independent risk factors for dementia and AD.

Association of executive function impairment, history of falls and physical performance in older adults: a cross-sectional population-based study in eastern France

OBJECTIVE

To estimate: (1) the association between executive function (EF) impairment and falls; and (2) the association of EF impairment on tests of physical function used in the evaluation of fall risk.

DESIGN

Cross-sectional study.

SETTING

Thirteen health examination centres in Eastern France.

PARTICIPANTS

Four thousand four hundred and eighty one community-dwelling older adults without dementia aged 65 to 97 years (mean age 71.8±5.4, women 47.6%).

MEASUREMENTS

Participants underwent a comprehensive medical assessment that included evaluations of EF using the Clock Drawing Test and of physical performance using the Timed Up and Go Test (TUG). Analysis used multivariable modified Poisson regression to evaluate the association between impaired EF and each of the fall outcomes (any fall, recurrent falls, fall-related injuries). Multivariable linear regression was used to evaluate the association between EF impairment and performance on the TUG and grip strength.

RESULTS

EF impairment, assessed using the clock drawing test, was present in 24.9% of participants. EF impairment was independently associated with an increased risk of any fall (RR=1.13, 95% CI (1.03, 1.25)) and major soft tissue fall-related injury (RR= 2.42, 95% CI (1.47, 4.00)). Additionally, EF impairment was associated with worse performance on the TUG (p<0.0001).

CONCLUSIONS

EF impairment among older adults without dementia was highly prevalent and was independently associated with an increased risk for falls, fall-related injuries and with decreased physical function. The use of the Clock Drawing Test is an easy to administer measure of EF that can be used routinely in comprehensive fall risk evaluations.

Cardiovascular risk factors and cognitive function in middle aged and elderly Lithuanian urban population: results from the HAPIEE study

Background

The purpose of this study was to examine associations between cardiovascular risk factors and cognitive ability in middle aged and elderly Lithuanian urban population.

Methods

Data from the survey performed in the framework of the HAPIEE (Health, Alcohol, Psychosocial Factors in Eastern Europe) study were presented. A random sample of 7,087 individuals aged 45–72 years was screened in 2006–2008.

Results

The scores of immediate recall and delayed verbal recall, cognitive speed and attention were significantly lower in men than in women; yet numerical ability scores were higher in men. Significant associations between lowered cognitive functions and previous stroke (in male OR = 2.52; 95% CI = 1.75-3.64; in female OR = 2.45; 95% CI = 1.75, 3.64) as well as ischemic heart disease history (among male OR = 1.28; 95% CI = 1.03-1.60) have been determined. Higher level of physical activity in leisure time (among female OR = 1.32; 95% CI = 1.03-1.69), poor self-rated health (among male OR = 1.57; 95% CI = 1.15-2.14) and poor quality of life (in male OR = 1.67; 95% CI = 1.07-2.61; in female OR = 2.81; 95% CI = 1.92-4.11) were related to lowered cognitive function.

Conclusions

The findings of the study suggest that associations between cardiovascular risk factors and lowered cognitive function among healthy middle-aged and elderly adults strongly depend on gender.

Cognitive impairment and the associated risk factors among the elderly in the Shanghai urban area: a pilot study from China

Objectives

Our study aimed to investigate the prevalence of cognitive impairment(CI) and the associated risk factors among elderly people in Shanghai urban area, China.

Methods

A population-based survey was conducted among people aged 55 years or older in urban areas of Shanghai. Face-to-face interviews were carried out to collect information including demographic characteristics, medical history, and medication use, etc. The validated Chinese version of the Mini-Mental State Examination(MMSE) was used to screen subjects with CI, and the criteria of CI were adjusted for education levels.

Results

A total of 3,176 home-living residents (≥55 years old) were included in the study. Among them, 266 people (102 men and 164 women) were identified as cognition impaired, with a prevalence of 8.38% (266/3,176, 95% CI: (8.26, 8.49)) for both genders, 9.21% (102/1,107,95% CI: (9.18, 9.33)) for men and 7.93% (164/2,069, 95% CI: (7.80, 8.09)) for women, respectively. Furthermore, we found that several significant risk factors, including social factors(education, number of children, marriage status, and family structure), physiological factors (age, blood glucose level, and obesity), factors on living styles(physical exercise, diet & chronic diseases), and genetic factor(ApoE), associated with CI onset.

Conclusions

This study confirms the high prevalence of CI among the elderly population in the Shanghai urban in China, similar to previous epidemiologic studies in Western countries. The putative risk factors associated with CI merit further investigated.

Design, methods and demographic findings of the DEMINVALL survey: a population-based study of Dementia in Valladolid, Northwestern Spain

Background

This article describes the rationale and design of a population-based survey of dementia in Valladolid (northwestern Spain). The main aim of the study was to assess the epidemiology of dementia and its subtypes. Prevalence of anosognosia in dementia patients, nutritional status, diet characteristics, and determinants of non-diagnosed dementia in the community were studied. The main sociodemographic, educational, and general health status characteristics of the study population are described.

Methods

Cross-over and cohort, population-based study. A two-phase door-to-door study was performed. Both urban and rural environments were included. In phase 1 (February 2009 – February 2010) 28 trained physicians examined a population of 2,989 subjects (age: ≥ 65 years). The seven-minute screen neurocognitive battery was used. In phase 2 (May 2009 – May 2010) 4 neurologists, 1 geriatrician, and 3 neuropsychologists confirmed the diagnosis of dementia and subtype in patients screened positive by a structured neurological evaluation. Specific instruments to assess anosognosia, the nutritional status and diet characteristics were used. Of the initial sample, 2,170 subjects were evaluated (57% female, mean age 76.5 ± 7.8, 5.2% institutionalized), whose characteristics are described. 227 persons were excluded for various reasons. Among those eligible were 592 non-responders. The attrition bias of non-responders was lower in rural areas. 241 screened positive (11.1%).

Discussion

The survey will explore some clinical, social and health related life-style variables of dementia. The population size and the diversification of social and educational backgrounds will contribute to a better knowledge of dementia in our environment.

Differential distribution of subjective and objective cognitive impairment in the population: a nation-wide twin-study

We report the prevalence of subjective cognitive impairment (SCI) and cognitive impairment no dementia (CIND), their socio-demographic profile, and the contribution of genetic background and shared familial environment to SCI and CIND. Subjects were 11,926 dementia-free twin individuals aged ≥65 from the Swedish Twin Registry. SCI was defined as subjective complaint of cognitive change without objective cognitive impairment and CIND was defined according to current criteria. Overall prevalence rates of SCI and CIND were 39% (95% CI 38-39%) and 25% (95% CI 24-25%). In multivariate GEE models, both SCI and CIND were older compared with people without any cognitive impairment. CIND were also less educated, more likely to be unmarried and to have lower socioeconomic status (SES). SCI individuals differed from persons with CIND as they were older, more educated, more likely to be married, and to have higher SES. Co-twin control analysis, which corrects for common genetic and shared environmental background, confirmed the association of low education with CIND. Probandwise concordance for SCI and CIND was 63% and 52% in monozygotic twins, 63% and 50% in dizygotic same-sex twins, and 42% and 29% in dizygotic unlike-sex twins. Tetrachoric correlations showed no significant differences between monozygotic and dizygotic same-sex twins. We conclude that subjective and objective cognitive impairment are both highly prevalent among nondemented elderly yet have distinct sociodemographic profiles. Shared environmental influences rather than genetic background play a role in the occurrence of SCI and CIND.