Prevalence of dementia in rural China: impact of age, gender and education

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.

Association between oral health and cognitive function among Chinese older adults: the Taizhou imaging study

BACKGROUND

We aimed to investigate the association between oral health and cognitive function in a sample of older adults from a Chinese rural community.

METHODS

The cross-sectional cognitive function of 677 individuals were assessed by Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA). A comprehensive profile of the oral health status was evaluated by questionnaire and clinical examination.

RESULTS

Multiple covariates-adjusted regression models demonstrated decayed teeth (DT) and decayed/missing/filled teeth (DMFT) were negatively associated with MoCA score (all p < 0.05). Calculus index (CI) and clinical attachment loss (CAL) were significantly associated with the lower MoCA, short-term memory and executive function score, respectively (all p < 0.05). Additionally, participants with missing teeth unrestored tend to get lower MMSE and MoCA scores (p < 0.05). The results also showed that increased DT and CI were modestly associated with higher odds of cognitive impairment (p < 0.05).

CONCLUSIONS

There is an association between oral health and global cognition. Poor periodontal status was strongly associated with worse global cognition performance, especially in the short-term memory and executive domain for the aging population.

Effect of Cold Fluid Compensatory Swallowing Combined with Balloon Dilation on the Treatment of Poststroke Cricopharyngeal Achalasia: A Pilot Randomized Controlled Trial

Objective

This study is aimed at comparing the treatment efficacy between catheter balloon dilation combined with cold fluid compensatory swallowing training and catheter balloon dilation alone on poststroke cricopharyngeal achalasia (CPA).

Methods

We conducted a single-blind, randomized controlled trial (RCT). Poststroke patients with CPA were divided into two groups: the control group (treated with catheter balloon dilation) and the trial group (catheter balloon dilation combined with cold fluid compensatory swallowing). Videofluoroscopic swallowing study (VFSS) was performed, and functional oral intake scale (FOIS) was used to evaluate and compare the swallowing function of patients in the 2 groups before and after intervention. Posttreatment VAS pain scores and recovery time were also measured.

Results

VFSS and FOIS scores in the two groups were improved after treatment (P < 0.05). In the trial group, VFSS scores in the pharyngeal phase and aspiration degree were significantly higher compared with the control group (P < 0.05) but not in the oral phase (P > 0.05). The difference in FOIS scores and patients' recovery time from intervention to eating mushy food between the trial and control groups was significant (P < 0.05), but not the VAS scores (P > 0.05).

Conclusion

The catheter balloon dilation combined with cold fluid compensatory swallowing was superior to catheter balloon dilation alone in terms of relieving dysphagia and reducing aspiration in patients with CPA following stroke. Long-term efficacy should be followed up with more objective and quantitative indicators in future studies.

The effect of illiteracy on performance in screening tools for dementia: A meta-analysis

INTRODUCTION

Research indicates that many tools designed for screening dementia are affected by literacy level. The objective of this study was to estimate the overall effects of this confounding factor. A meta-analysis was conducted to evaluate differences in performance in dementia screening tools between literate and illiterate individuals.

METHOD

Electronic databases were searched from 1975 to June 2021 to identify empirical studies examining performance in dementia screening tools in literate and illiterate individuals over 50 years old. Data for effect sizes, participant demographic information, and study information were extracted.

RESULTS

We identified 27 studies methodologically suitable for meta-analysis. Multi-level random-effects modeling demonstrated a significant overall effect, with literate participants scoring significantly higher than illiterate participants (g = -1.2, 95% CI = -1.47, -0.95, p < .001). Moderator analyses indicated significant effects of test type and the presence of cognitive impairment on the extent of the difference in performance between literate and illiterate participants. The difference in performance between groups was smaller in screening tests modified for illiterate individuals (p < .01), and in individuals with cognitive impairment (p < .001).

CONCLUSIONS

Our findings substantiate the unsuitability of many dementia screening tools for individuals who are illiterate. The results of this systematic review and meta-analysis emphasize the need for the development and validation of tools that are suitable for individuals of all abilities.

A comparison of the Mini-Mental State Examination (MMSE) with the Montreal Cognitive Assessment (MoCA) for mild cognitive impairment screening in Chinese middle-aged and older population: a cross-sectional study

BACKGROUND

The Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) are the most commonly used scales to detect mild cognitive impairment (MCI) in population-based epidemiologic studies. However, their comparison on which is best suited to assess cognition is scarce in samples from multiple regions of China.

METHODS

We conducted a cross-sectional analysis of 4923 adults aged ≥55 years from the Community-based Cohort Study on Nervous System Diseases. Objective cognition was assessed by Chinese versions of MMSE and MoCA, and total score and subscores of cognitive domains were calculated for each. Education-specific cutoffs of total score were used to diagnose MCI. Demographic and health-related characteristics were collected by questionnaires. Correlation and agreement for MCI between MMSE and MoCA were analyzed; group differences in cognition were evaluated; and multiple logistic regression model was used to clarify risk factors for MCI.

RESULTS

The overall MCI prevalence was 28.6% for MMSE and 36.2% for MoCA. MMSE had good correlation with MoCA (Spearman correlation coefficient = 0.8374, p < 0.0001) and moderate agreement for detecting MCI with Kappa value of 0.5973 (p < 0.0001). Ceiling effect for MCI was less frequent using MoCA versus MMSE according to the distribution of total score. Percentage of relative standard deviation, the measure of inter-individual variance, for MoCA (26.9%) was greater than for MMSE (19.0%) overall (p < 0.0001). Increasing age (MMSE: OR = 2.073 for ≥75 years; MoCA: OR = 1.869 for≥75 years), female (OR = 1.280 for MMSE; OR = 1.163 for MoCA), living in county town (OR = 1.386 and 1.862 for MMSE and MoCA, respectively) or village (OR = 2.579 and 2.721 for MMSE and MoCA, respectively), smoking (OR = 1.373 and 1.288 for MMSE and MoCA, respectively), hypertension (MMSE: OR = 1.278; MoCA: OR = 1.208) and depression (MMSE: OR = 1.465; MoCA: OR = 1.350) were independently associated with greater likelihood of MCI compared to corresponding reference group in both scales (all p < 0.05).

CONCLUSIONS

MoCA is a better measure of cognitive function due to lack of ceiling effect and with good detection of cognitive heterogeneity. MCI prevalence is higher using MoCA compared to MMSE. Both tools identify concordantly modifiable factors for MCI, which provide important evidence for establishing intervention measures.

Status and Factors of Cognitive Function Among Older Adults in Urban China

The present study aimed to examine the current status and influencing mechanisms of different demographic factors associated with cognitive function in urban Chinese older adults. A total of 644 older adults from 14 communities in urban China (e.g., Shanghai, Beijing, and Wuxi) were investigated by using the Mini-Mental State Examination and the Repeatable Battery for the Assessment of Neuropsychological Status. The results indicated that the overall cognitive function of older adults in urban China was normal. We found an aging effect on cognitive level, and cognitive function declined more rapidly after age 80. Older age, unmarried status, and lower occupational cognitive requirements increased the likelihood of cognitive risk. Higher educational levels and active engagement in exercise may contribute to cognitive reserve and have a protective effect on cognitive decline in late life. Further study is needed to develop appropriate interventions to improve the mental health of older people.

Global Prevalence of Young-Onset Dementia: A Systematic Review and Meta-analysis

Importance

Reliable prevalence estimates are lacking for young-onset dementia (YOD), in which symptoms of dementia start before the age of 65 years. Such estimates are needed for policy makers to organize appropriate health care.

Objective

To determine the global prevalence of YOD.

Data Sources

The PubMed, Embase, CINAHL, and PsycInfo databases were systematically searched for population-based studies on the prevalence of YOD published between January 1, 1990, and March 31, 2020.

Study Selection

Studies containing data on the prevalence of dementia in individuals younger than 65 years were screened by 2 researchers for inclusion in a systematic review and meta-analysis.

Data Extraction and Synthesis

Prevalence estimates on 5-year age bands, from 30 to 34 years to 60 to 64 years, were extracted. Random-effects meta-analyses were conducted to pool prevalence estimates. Results were age standardized for the World Standard Population. Heterogeneity was assessed by subgroup analyses for sex, dementia subtype, study design, and economic status based on the World Bank classification and by meta-regression.

Main Outcomes and Measures

Prevalence estimates of YOD for 5-year age bands.

Results

A total of 95 unique studies were included in this systematic review, of which 74 with 2 760 379 unique patients were also included in 5-year age band meta-analyses. Studies were mostly conducted in Europe and in older groups in Asia, North America, and Oceania. Age-standardized prevalence estimates increased from 1.1 per 100 000 population in the group aged 30 to 34 years to 77.4 per 100 000 population in the group aged 60 to 64 years. This gives an overall global age-standardized prevalence of 119.0 per 100 000 population in the age range of 30 to 64 years, corresponding to 3.9 million people aged 30 to 64 years living with YOD in the world. Subgroup analyses showed prevalence between men and women to be similar (crude estimates for men, 216.5 per 100 000 population; for women, 293.1 per 100 000 population), whereas prevalence was lower in high-income countries (crude estimate, 663.9 per 100 000 population) compared with upper-middle-income (crude estimate, 1873.6 per 100 000 population) and lower-middle-income (crude estimate, 764.2 per 100 000 population) countries. Meta-regression showed that age range (P < .001), sample size (P < .001), and study methodology (P = .02) significantly influenced heterogeneity between studies.

Conclusions and Relevance

This systematic review and meta-analysis found an age-standardized prevalence of YOD of 119.0 per 100 000 population, although estimates of the prevalence in low-income countries and younger age ranges remain scarce. These results should help policy makers organize sufficient health care for this subgroup of individuals with dementia.

Study Registration

PROSPERO CRD42019119288.

Sex differences in the incidence and prevalence of young-onset Alzheimer's disease: A meta-analysis

OBJECTIVES

The lifetime incidence of Alzheimer's disease is higher in women than in men, but it remains unclear if similar sex differences exist in young-onset Alzheimer's disease (YOAD). This systematic review test the hypothesis that women have a higher prevalence and incidence of YOAD than men.

METHODS

We searched Pubmed and Embase (inception to 11 June 2020) for original publications of population-based observational studies with data on the prevalence and/or incidence of YOAD, defined as a medical diagnosis of Alzheimer's disease before the age of 65 years. Data on cross-sectional and/or prospective numbers, percentages, incidences, and incidence rates (in person-years) were derived from included studies. Quality assessment was done using the Nottingham Ottawa Scale. Meta-analyses were done to test the hypothesis that women have a higher prevalence and incidence of YOAD than men.

RESULTS

After screening of 3252 titles, 12 articles were included. The pooled prevalence was 0.4% (confidence interval [CI] = 0.1-2.1) in women and 0.2% (CI = 0-1.2) in men (six studies, relative risk [RR] = 1.54, CI = 0.69-3.44, I2  = 38%). The pooled incidence was 0.02% (CI = 0.01-0.08) in women and 0.01% (CI = 0-0.05) in men (five studies, RR = 1.50, CI = 0.91-2.48, I2  = 0%). The incidence rates per 100,000 person-years ranged from 0 to 132 in women and from 0 to 42 in men.

CONCLUSIONS

Given the low prevalence and wide CIs, no firm conclusions can be drawn. Large-scale studies are required to verify that women are more likely than men to develop YOAD.

The Prevalence of Dementia: A Systematic Review and Meta-Analysis

Dementia is a severe neurodegenerative disorder and it can be categorized into several subtypes by different pathogenic causes. We sought to comprehensively analyzed the prevalence of dementia from perspectives of geographic region (Asia, Africa, South America, and Europe/North America), age, and gender. We searched PubMed and EMBASE for relevant articles on dementia published from January 1985 to August 2019. In these studies, analyses were stratified by geographic region, age, and gender. Meta-regression was conducted to identify if there were significant differences between groups. We included forty-seven studies. Among the individuals aged 50 and over in the community, the pooled prevalence for all-cause dementia, Alzheimer's disease, and vascular dementia were 697 (CI95%: 546-864) per 10,000 persons, 324 (CI95%: 228-460) per 10,000 persons, and 116 (CI95%: 86-157) per 10,000 persons, respectively. In our study, the prevalence of all-type dementia in individuals aged 100 years and older (6,592 per 10,000 cases) is 244 times higher than in those aged 50-59 (27 per 10,000 cases). The number of people living with dementia approximately doubles every five years. The prevalence was greater in women than in men (788 cases versus 561 cases per 10,000 persons) in overall analysis. In individuals aged 60 to 69 years, AD prevalence in females was 1.9 times greater than that in males (108 cases versus 56 cases per 10,000 persons), while the prevalence of VaD was 1.8 times greater in males than in females (56 cases versus 32 cases per 10,000 persons). Prevalence rate was higher in Europe and North America than in Asia, Africa, and South America.

Late-Life Cognitive Trajectories and their Associated Lifestyle Factors

Significant variability exists in the trajectories of late-life cognitive decline; however, their associated lifestyle factors remain less studied. We examined these trajectories among elderly participants from the recent five waves (at three-year intervals) of the Chinese Longitudinal Healthy Longevity Study (CLHLS) from 2002 to 2014. Participants from this cohort were included if they completed at least four waves of measurements. Mini-Mental State Examination (MMSE) scores, demographics, medical diagnoses (e.g., hypertension, diabetes, and heart disease), and lifestyle-related information (e.g., smoking, drinking alcohol, and exercise) were collected from participants (N = 2,584; mean age at baseline = 73.3) at least four times across 12 years. MMSE scores were entered into a latent class mixed model analysis. Subsequently, demographic, medical, and lifestyle predictors were entered into multinomial logistic regression models to predict the trajectories. One of the four emerged classes (no decline) was characterized by an absence of cognitive decline; the other three exhibited various degrees of cognitive decline. The inclusion of lifestyle factors significantly improved the prediction of the different trajectories, above and beyond demographics and medical variables; the 'no decline' class was significantly more likely to report exercising regularly. Changes in cognitive functioning across the late-life period are characterized by multiple trajectories. Cognitive decline is not inevitable across the late-life period; the absence of such cognitive decline is partly explained by certain lifestyle factors.

Association of sex differences in dementia risk factors with sex differences in memory decline in a population-based cohort spanning 20-76 years

Sex differences in late-life memory decline may be explained by sex differences in dementia risk factors. Episodic memory and dementia risk factors were assessed in young, middle-aged and older adults over 12 years in a population-based sample (N = 7485). For men in midlife and old age, physical, cognitive and social activities were associated with less memory decline, and financial hardship was associated with more. APOE e4 and vascular risk factors were associated with memory decline for women in midlife. Depression, cognitive and physical activity were associated with memory change in older women. Incident midlife hypertension (β = - 0.48, 95% CI - 0.87, - 0.09, p = 0.02) was associated with greater memory decline in women and incident late-life stroke accounted for greater memory decline in men (β = - 0.56, 95% CI - 1.12, - 0.01), p = 0.05). Women have fewer modifiable risk factors than men. Stroke and hypertension explained sex differences in memory decline for men and women respectively.

Analysis of Risk Factors for Cognitive Dysfunction in Disabled Elderly Patients in Chengdu, China

Background

With the aging population comes an increase in functional disability that leads to dependency and institutionalization, as well as social, medical, and economic challenges. This study aimed to classify and assess the factors affecting cognitive deficits in disabled elderly people.

Material/Methods

Disabled patients ≥60 years old were assessed by face-to-face cross-sectional surveys, which were conducted using advanced peer-to-peer software. The ability to perform daily life tasks was assessed using the Modified Barthel Index. Cognitive function was evaluated with the Mini-cognitive assessment instrument. Using these surveys, 9471 individuals were included in this study. The rank-sum test was used to investigate differences between groups. Disordered multi-class logistic regression was used to correct related confounding factors for multivariate analysis.

Results

The ratios of normal cognitive function, cognitive impairment, and dementia were 3.71%, 38.59%, and 57.70%, respectively. The univariate analysis and multivariate analysis showed that older individuals (≥80 years), women, illiterate individuals, and lonely persons were more prone to dementia. Moreover, a history of hypertension, diabetes, osteoporosis, and fractures were significantly associated with dementia.

Conclusions

The proportion of dementia in the elderly disabled patients is very high (57.7%) in Chengdu City. Age (≥80 years), female sex, education level (illiterate individuals), living conditions, and chronic disease were closely correlated with cognitive functions.

Efficacy of a self-management program in patients with chronic viral hepatitis in China

Background

Chronic hepatitis, mainly B or C, increases the risk of hepatocellular carcinoma and remains an emerging issue in the globe. China has high rates of liver cancer incidence and mortality in the world. To address such challenges, adequate management of chronic hepatitis is required. Self-management education is one alternative for improving the hepatitis patients’ knowledge of the disease, mental health, and clinical management.

This study aimed to examine the quality of life (QOL), psychological effects, and behavioral changes of a self-management program which allows continuity of care for chronic hepatitis B and C patients.

Method

In a six-month, randomized controlled trial, we invited 73 chronic hepatitis B/C inpatients to receive (i) two face-to-face education sessions provided by a nurse during hospitalization, and monthly telephone counseling at home after discharge; (ii) or usual care treatment (control group). The primary endpoint (patients’ QOL) and secondary outcomes (including self-efficacy, depression symptoms, perceived cognition of illness and behavioral changes) were assessed. In addition, we conducted qualitative data analysis to facilitate the evaluation of the interventions.

Results

Sixty (82.2%) out of 73 eligible patients with chronic hepatitis B/C (aged 34.9 ± 8.9 years) participated in the study. The intervention group (n = 30) significantly improved on outcomes including QOL, self-efficacy, perceived cognition of illness, and behavioral changes, whereas the control group significantly decreased their healthy behaviors. In terms of behavioral changes, alcohol avoidance, dietary adherence, and stress management also improved in the intervention group. However, there were no significant improvements in symptoms of depression. Most participants (80%) in the intervention group stated that they benefited from the program.

Conclusions

This program contributed to patients’ acquisition of self-management skills to cope with their illnesses, and significantly improved their QOL. This program serves as a reminder for nurses who care for patients with chronic viral hepatitis to acquire these skills as it would help them address the daily needs of their patients.

Trial registration

UMIN000025378. Registered December 23, 2016.

Electronic supplementary material

The online version of this article (10.1186/s12912-019-0366-7) contains supplementary material, which is available to authorized users.

Past Taurine Intake Has a Positive Effect on Present Cognitive Function in the Elderly

This study investigated the associations between dietary history of past taurine intake and cognitive function in the elderly. Subjects of this study were 40 elderly persons with dementia (men 14, women 26) and 37 normal elderly persons (men 5, women 32). Data were collected using questionnaires by investigator-based interview to the elderly and family caregivers. We examined their general characteristics, anthropometric data, cognitive function, and taurine index. Cognitive function was measured using MMSE-DS and higher score means better cognitive function. As dietary history of past taurine intake, taurine index was evaluated by scoring the intake frequency of 41 kinds of taurine-containing foods. Part correlation analysis (sex, age, and school educational period correction) was used to analyze associations between taurine index and cognitive function. The analysis of all data was carried out by the SPSS 20.0 program for windows. The age, height, weight, and BMI of elderly with dementia showed no statistical significance compared to normal elderly. The elderly with dementia had significantly higher school education period (7.4 years) than the normal elderly (4.8 years) (p < 0.01). Nevertheless, the average total score of cognitive function (MMSE-DS) of the elderly with dementia (18.1 points) was significantly lower than score of the normal elderly (21.7 points) (p < 0.05). The average taurine index of the elderly with dementia (104.7 points) was significantly lower than average taurine index of the normal elderly (123.7 points) (p < 0.01). There were positive correlations between total taurine index and total score of cognitive function in all the elderly subjects (p < 0.05). In particular, as taurine index was higher, there were significantly higher scores of cognitive function such as 'time orientation' and 'judgement and abstract thinking' (p < 0.01). In conclusion, these results suggest that past taurine intake may have a positive effect on present cognitive function in the elderly.

Prevalence of Mental Disorders among Older Chinese People in Tianjin City

OBJECTIVE

Population aging is accelerating across the world, and older people have a higher risk of mental disorders. Most studies focus on one mental disorder, and only report the current prevalence. Besides, these studies use screening scales for symptoms of mental disorders, which may induce biased results. In this study, we used data for diagnoses based on SCID that had been administered by trained psychiatrists to explore the 1-month and lifetime prevalence of mental disorders among a Chinese aged cohort.

METHODS

Data for this study was derived from the Tianjin Mental Health Survey. Participants were first screened using a General Health Questionnaire and 9 additional items on other risk factors for mental disorders, and then diagnosed with the Chinese version of Structured Clinical Interview for Diagnostic and Statistical Manual (DSM-IV) Axis I disorders. A total of 3,325 people aged 60 and above had valid information, and 1,486 completed the SCID interview.

RESULTS

The weighted 1-month prevalence of mental disorders was 14.27%, whereas the lifetime prevalence of mental disorders was 24.20%. Most of these participants were female, older, currently not married, of lower education level, and with poor family economic status. Organic mental disorders had the highest 1-month prevalence (4.45%), whereas mood disorder was highest for the lifetime prevalence (9.75%).

CONCLUSION

Older Chinese people had a high prevalence of mental disorders. Further research and health services innovations are needed to address the high prevalence in these subgroups among older people.

The impact of methods to handle missing data on the estimated prevalence of dementia and mild cognitive impairment in a cross-sectional study including non-responders

OBJECTIVE

Although several statistical methods for adjusting for missing data have been developed and are widely applied in research, few studies have investigated these methods in adjusting for missingness in datasets that aim to estimate the prevalence of dementia. We attempted to develop a more feasible approach for handling missingness in a cross-sectional study among elderly.

METHODS

Five methods of estimating prevalence, including stratified weighting (SW), inverse-probability weighting (IPW), hot deck imputation (HDI), ordinal logistic regression (OLR) and multiple imputation (MI), were applied to handle the missing data yielded by a dataset that include 2231 non-responders.

RESULTS

Compared with the results of the complete case analysis, the differences in the prevalence rates of dementia and mild cognitive impairment (MCI) calculated by the prevalence-estimating methods after adjusting for non-responders were less than 7% and 6%, respectively. In contrast to the results of other methods, the estimated prevalence of dementia and MCI calculated by MI increased when more predictive factors were included, and the lowest rate of missing data was achieved using MI. Using the participants' ages, the cognitive screening sores and activity of daily life sores as predictive variables when correcting for missingness induced relatively larger effects on the estimated dementia prevalence.

CONCLUSIONS

When adjusting for missingness while estimating the prevalence of dementia in cross-sectional studies, a simple method, such as SW, is recommended when limited information is available, whereas MI is the preferred method when additional information is available. Further simulation studies are needed to determine the optimal approach.

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.

Optimal Cutoff Scores for Alzheimer's Disease Using the Chinese Version of Mini-Mental State Examination Among Chinese Population Living in Rural Areas

To explore the optimal cutoff score for initial detection of Alzheimer's Disease (AD) through the Chinese version of Mini-Mental State Examination (CMMSE) in rural areas in China, we conducted a cross-sectional study within the Linxian General Population Nutritional Follow-up study. 16,488 eligible cohort members participated in the survey and 881 completed the CMMSE. Among 881 participants, the median age (Interquartile range) was 69.00 (10.00), 634 (71.92%) were female, 657 (74.57%) were illiterate, 35 (3.97%) had 6 years of education or higher, and 295 (33.48%) were diagnosed with AD. By reducing the CMMSE criteria for illiterate to 16 points, primary school to 19 points, and middle school or higher to 23 points, the efficiency of Chinese version of Mini-Mental State Examination can be significantly improved for initial detection of AD in rural areas in China, especially in those nutrition deficient areas.

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.

Validation of Neuropsychological Tests to Screen for Dementia in Chinese Patients With Parkinson's Disease

To compare the accuracy of different neuropsychological tests and their combinations for deriving reliable cognitive indices for dementia diagnosis in Parkinson's disease (PD). One hundred forty consecutive patients with PD were recruited and administrated an extensive battery of neuropsychological tests. Discriminant analysis and receiver-operator characteristic curve were used to evaluate their correct classifications and validity. Patients with PD having dementia (PDD; 23.5%) performed significantly worse in all tests than patients without dementia. Age of onset, disease duration, Hoehn-Yahr grade, Unified Parkinson's Disease Rating Scale part III scores, and education were associated with dementia in patients with PD. Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment, and Block Design (BD) showed better specificity and sensitivity when used alone, and combined use of MMSE and BD further increased the validity. Our results indicated that the accuracy of MMSE was better in dementia diagnosis of Chinese patients with PD, and combined use of MMSE and BD could further increase the validity of dementia diagnosis.

Prevalence of dementia-associated disability among Chinese older adults: results from a national sample survey

OBJECTIVE

Due to rapid population aging and a tidal wave of dementia, dementia has become an urgent public health issue in China. Few large-scale surveys on dementia have been conducted in China and little was known about the magnitude of dysfunction and disability caused by dementia. In this study, using national sample survey data, we aimed to describe the prevalence rate of dementia-associated disability, its associated factors, and daily activities and social functions of people with dementia-associated disability in Chinese older adults.

METHODS

We used the second China National Sample Survey on Disability, comprising 2,526,145 persons from 771,797 households. Identification for dementia was based on consensus manuals. Standard weighting procedures were used to construct sample weights considering the multistage stratified cluster sampling survey scheme. Population weighted numbers, weighted prevalence, and the odd ratios (ORs) were calculated.

RESULTS

The prevalence rate of dementia-associated disability was 4.64% (95% CI: 4.26-5.01) and it accounted for 41.03% of mental disability among Chinese older adults. Urban residence (OR: 1.33 [1.12-1.57]), older age (80+ years) (OR: 4.12 [3.38-.03]), illiteracy (OR: 1.79 [1.27-2.53]), and currently not married (OR: 1.15 [1.00-1.32]) were associated with increased risk of dementia-associated disability. Compared with those with mental disability of other causes and those with other types of disabilities, older adults with dementia-asscoiated disability were more likely to have severe or extreme difficulty in daily activities and social functions.

CONCLUSION

Countermeasures are warranted to obtain a more precise overview of dementia in China, and strategies on enhancing early identification, treatment, and rehabilitation should be developed for people with dementia.

Using the Chinese version of Memorial Delirium Assessment Scale to describe postoperative delirium after hip surgery

Objective: Memorial Delirium Assessment Scale (MDAS) assesses severity of delirium. However, whether the MDAS can be used in a Chinese population is unknown. Moreover, the optimal postoperative MDAS cutoff point for describing postoperative delirium in Chinese remains largely to be determined. We therefore performed a pilot study to validate MDAS in the Chinese language and to determine the optimal postoperative MDAS cutoff point for delirium.

Methods: Eighty-two patients (80 ± 6 years, 21.9% male), who had hip surgery under general anesthesia, were enrolled. The Confusion Assessment Method (CAM) and Mini-Mental State Examination (MMSE) were administered to the patients before surgery. The CAM and MDAS were performed on the patients on the first, second and fourth postoperative days. The reliability and validity of the MDAS were determined. A receiver operating characteristic (ROC) curve was used to determine the optimal Chinese version MDAS cutoff point for the identification of delirium.

Results: The Chinese version of the MDAS had satisfactory internal consistency (α = 0.910). ROC analysis obtained an average optimal MDAS cutoff point of 7.5 in describing the CAM-defined postoperative delirium, with an area under the ROC of 0.990 (95% CI 0.977–1.000, P < 0.001).

Conclusions: The Chinese version of the MDAS had good reliability and validity. The patients whose postoperative Chinese version MDAS cutoff point score was 7.5 would likely have postoperative delirium. These results have established a system for a larger scale study in the future.

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.

The assessment of cognitive impairment suspected of dementia in Polish elderly people: results of the population-based PolSenior Study

The growing incidence of dementia in ageing societies is a major concern of health care organizations. Because of its detrimental influence on the mental and functional statuses of elderly people, it leads to increased economic burdens caused by the social and financial needs of patients with dementia and their caregivers. There has been no data concerning the prevalence of dementia in the elderly in the general Polish community so far. The main aim of the study was to assess the prevalence of cognitive impairment suspected of dementia among the Polish elderly and the relationships between cognitive performance and age, gender, place of residence and educational status. The presented data was the result of nationwide, multicentre PolSenior Study conducted from 2007 to 2011 in the Polish elderly population. Cognitive functions were evaluated using Mini-Mental State Examination (MMSE) performed by pre-trained nurses. The result of MMSE lower than 24 points was classified as cognitive impairment suspected of dementia and divided according to its severity into three stages: mild, moderate and severe dementia. The results were analysed in two ways: raw MMSE and MMSE scores after Mungas adjustment (MMSEadj), that is, corrected for age and educational level, and these were compared. To verify the suspicion of dementia an assessment was complemented by an interview of carers for the occurrence and course of memory disorders, treatment of dementia and by functional status assessment. In order to assess the prevalence of suspicion of dementia in the general Polish population, statistical analyses based on weighting were done. The suspicion of dementia on the basis of raw MMSE was made in 20.4% of respondents aged 65years and more, and after Mungas adjustment in 12.1% of older subjects. The prevalence of cognitive impairment grew with increasing age, as well as depending on the educational status of elderly respondents in both types of analyses; raw MMSE and MMSEadj. There was no significant difference in the prevalence of cognitive impairment according to gender in the general population (raw MMSE); however in analyses including MMSEadj results, the suspicion of dementia was made more often among men. Suspicion of dementia based on raw MMSE and MMSEadj results was made significantly more often among men than women at the age of 65-69years, and significantly more often among the oldest women, aged 90years and more. Suspicion of dementia was diagnosed more often in respondents living in rural communities (based on raw MMSE, but not on MMSEadj), which might be related to the differences in their educational status.

The association between educational level and dementia in rural Tanzania

The majority of people with dementia worldwide live in developing countries. Studies from the developed world have reported an association between lower educational attainment and dementia, but there are few data from the developing world where literacy and educational levels are frequently much lower. In this study we assessed the association between education and dementia prevalence in a rural Tanzanian setting.

Methods

In phase I, 1198 individuals aged 70 and over were assessed using the Community Screening Instrument for Dementia (CSI-D). In phase Ii a stratified sample of those seen in phase I were fully assessed and a clinical diagnosis based on DSM-IV criteria was made where appropriate. Information regarding literacy, highest attained educational level and occupation were also collected.

Results

The median subject cognitive score on the CSI-D was 25.7 (IQR 22.7 to 28.0) for females and 27.7 (IQR 25.7 to 29.4) for males. This difference was significant (U=117770.0, z= -9.880, p<0.001). In both males and females a lower CSI-D subject cognitive score was significantly associated with having had no formal education (U=34866.5, z= -6.688, p<0.001, for females; U=20757.0, z= -6.278, p<0.001, for males). After adjusting for the effect of age, having no formal education was significantly associated with greater odds of having 'probable dementia' by CSI-D, as was illiteracy. Amongst those interviewed in phase II, there was no significant difference in literacy or education between those with diagnosed DSM-IV dementia and those without.

Conclusion

In this rural Tanzanian population, we found a significant association between low levels of education and dementia by CSI-D. This relationship was not significant in cases meeting DSM-IV criteria for dementia.

The attenuation of retinal nerve fiber layer thickness and cognitive deterioration

Thinner retinal nerve fiber layer (RNFL) has been reported in Alzheimer's disease (AD) patient. However, whether changes in RNFL thickness can predict the cognitive deterioration remains unknown. We therefore set out a prospective clinical investigation to determine the potential association between the attenuation of RNFL thickness and the deterioration of cognitive function over a period of 25 months. We assessed cognitive function using the Repeatable Battery for the Assessment of Neuropsychological Status and measured RNFL thickness employing optical coherence tomography in 78 participants (mean age 72.31 ± 3.98 years, 52% men). The participants were categorized as stable participants whose cognitive status remained no change (N = 60) and converted participants whose cognitive status deteriorated (N = 18). We found that there was an association between the attenuation of superior quadrant RNFL thickness and the deterioration of cognitive function in the stable participants. In the converted participants, however, there was an inverse association between the reduction of inferior quadrant RNFL thickness and decline of cognitive functions [scores of list recall (R = -0.670, P = 0.002), adjusted (R = -0.493, P = 0.031)]. These data showed that less reduction in the inferior quadrant of RNFL thickness might indicate a higher risk for the patients to develop cognitive deterioration. These findings have established a system to embark a larger scale study to further test whether changes in RNFL thickness can serve as a biomarker of AD, and would lead to mechanistic studies to determine the cellular mechanisms of cognitive deterioration.

Prevalence studies of dementia in mainland china, Hong Kong and taiwan: a systematic review and meta-analysis

BACKGROUND

Many studies have considered the prevalence of dementia in mainland China, Hong Kong and Taiwan. However, area level estimates have not been produced. This study examines area differences across mainland China, Hong Kong and Taiwan adjusting for the effect of methodological factors with the aim of producing estimates of the numbers of people with dementia in these areas.

METHOD AND FINDINGS

A search of Chinese and English databases identified 76 dementia prevalence studies based on samples drawn from mainland China, Hong Kong and Taiwan between 1980 and 2012. A pattern of significantly decreasing prevalence was observed from northern, central, southern areas of mainland China, Hong Kong and Taiwan. Area variations in dementia prevalence were not explained by differences in methodological factors (diagnostic criteria, age range, study sample size and sampling method), socioeconomic level or life expectancy between areas. The results of meta-analysis were applied to current population data to provide best estimate. Based on the DSM-IV diagnostic criteria, the total number of people aged 60 and over with dementia in mainland China, Hong Kong and Taiwan is 8.4 million (4.6%, 95% CI: 3.4, 5.8) and in northern, central and southern areas are 3.8 (5.1%, 95% CI: 4.1, 6.1), 3.2 (4.4%, 95% CI: 3.2, 5.6) and 1.2 (3.9%, 95% CI: 2.3, 5.4) million respectively. These estimates were mainly based on the studies existing in highly developed areas and potentially affected by incomplete and insufficient data.

CONCLUSIONS

The findings of this review provide a robust estimate of area differences in dementia prevalence. Application of the estimated prevalence to population data reveals the number of people with dementia is expected to double every 20 years, areas in mainland China will be facing the greatest dementia challenge.

Multi-state Markov model in outcome of mild cognitive impairments among community elderly residents in Mainland China

BACKGROUND

Although knowledge of established risk factors for Alzheimer's disease (AD) can logically contribute to the search for predictors of the progression of cognitive impairment, it has not yet been firmly established where in the cognitive impairment process these risk factors exert their effects and how to predict quantitatively for the progression of mild cognitive impairments (MCI) to AD. This study aimed to determine whether known risk factors increased the risk of progression from MCI to AD and to make prediction based on transition probabilities.

METHODS

Based on ten examinations of 600 community-dwelling MCI residents and cognitive assessments to classify individuals into MCI, global impairment, and AD, a multi-state Markov Cox's regression model was used and the hazard ratios with their confidence intervals and transition probabilities were estimated.

RESULTS

Multivariate analysis showed that gender, age, and hypertension were statistically significant predictors of transition from MCI to global impairment; age, education, and reading statistically influenced transition from global impairment to MCI; gender, age, hypertension, diabetes, and apolipoprotein E geneε4 status were statistically associated with transition from global impairment to AD. Subjects at MCI were more likely (67%) to remain in that cognitive state at the next cognitive assessment than to transition to cognitive deterioration. For global impairment, probability of remaining in the same state was only 18% and that of forward transition was three times more likely than that of backward transition.

CONCLUSIONS

Known risk factors influenced differently for different transitions. Transition from global impairment was more likely to worsen to severe cognitive deterioration than transition from MCI.

Role of social support in cognitive function among elders

AIMS AND OBJECTIVES

To examine cognitive function and its relationships to demographic characteristics and social support among elders in central China.

BACKGROUND

Cognitive decline is prevalent among elders. Few studies have explored the relationship between social support and cognitive function among elders.

DESIGN

A cross-sectional, descriptive correlational study.

METHODS

A quasi-random, point of reference sample of 120 elders residing in central China was recruited for study. Instruments used included a: Socio-demographic Questionnaire, the Multidimensional Scale on Perceived Social Support and the Mini-Mental State Examination. Hierarchical multiple regression was performed to examine the relationships among demographic variables, social support and cognitive function.

RESULTS

Age, education and social support accounted for 45·2% of the variance in cognitive function. Family support was the strongest predictor of cognitive function. Elders who had higher educational levels and more family support had better cognitive function. Relevance to clinical practice.  Community healthcare providers should consolidate social support among elders in China and use family support interventions to reduce or delay cognitive decline, especially among those of increased age who are illiterate.

CONCLUSION

Elders who had higher educational level and more family support had better cognitive function levels. Interventions that include family support are needed to improve cognitive function among elders in China.

Relationship between education and dementia: an updated systematic review

OBJECTIVE

The purpose of this study was to review the relationship between education and dementia.

METHODS

A systematic literature review was conducted of all published studies examining the relationship between education and dementia listed in the PubMed and PsycINFO databases from January 1985 to July 2010. The inclusion criteria were a measure of education and a dementia diagnosis by a standardized diagnostic procedure. Alzheimer disease and Total Dementia were the outcomes.

RESULTS

A total of 88 study populations from 71 studies met inclusion criteria. Overall, 51 studies (58%) reported significant effects of lower education on risk for dementia, whereas 37 studies (42%) reported no significant relationship. A relationship between education and risk for dementia was more consistent in developed regions compared with developing regions. Age, sex, race/ethnicity, and geographical region moderated the relationship.

CONCLUSIONS

Lower education was associated with a greater risk for dementia in many but not all studies. The level of education associated with risk for dementia varied by study population and more years of education did not uniformly attenuate the risk for dementia. It seemed that a more consistent relationship with dementia occurred when years of education reflected cognitive capacity, suggesting that the effect of education on risk for dementia may be best evaluated within the context of a lifespan developmental model.

High prevalence of mild cognitive impairment and Alzheimer's disease in arabic villages in northern Israel: impact of gender and education

The prevalence of mild cognitive impairment (MCI) and Alzheimer's disease (AD) have not been well been studied in Arab populations. In a door-to-door study of all residents aged ≥ 65 years in Wadi-Ara, an Arab community in northern Israel, we estimated the prevalence of AD, MCI, and the risk of conversion to AD. Subjects were classified as cognitively normal, MCI, AD, or other based on neurological and cognitive examination (in Arabic). MCI subjects were re-examined (interval ≥ 1 year) to determine conversion to AD and contributions of age, gender, and education to the probability of conversion. Of the 944 participants (96.6% of those approached; 49.4% men), 92 (9.8%) had AD. An unusually high prevalence of MCI (n = 303, 32.1%) was observed. Since the majority of women (77.2%) had no schooling, we estimated the effect of gender on the risk of AD and MCI among subjects without schooling and of school years among men. Among subjects with no schooling (n = 452), age (p = 0.02) and female gender (p < 0.0001) were significant predictors of AD, whereas risk of MCI increased only with age (p = 0.0001). Among men (n = 318), age increased the risk (p < 0.0001), school years reduced the risk of AD (p = 0.039) and similarly for MCI [age (p = 0.0001); school years (p = 0.0007)]. Age (p = 0.013), but not gender or school years, was a significant predictor of conversion from MCI to AD (annual rate 5.7%). The prevalence of MCI and AD are unusually high in Wadi Ara, while the rate of conversion from MCI to AD is low. Yet unidentified genetic factors might underlie this observation.

Cognitive impairment using education-based cutoff points for CMMSE scores in elderly Chinese people of agricultural and rural Shanghai China

OBJECTIVES

To evaluate cognitive impairment (CI) in rural China using the Chinese version of the Mini-Mental Status Examination (CMMSE) and compare the prevalence of CI using two different cutoff points.

MATERIALS & METHODS

A population-based survey was conducted of 2809 people aged 60 years and above in a community of two towns (Huaxin and Xujing) in the Qingpu district, located in the western suburb of Shanghai. Face-to-face interviews were carried out to collect relevant information with questionnaires. The Chinese version of the Mini-Mental State Examination with either a 23/24 cutoff point or a cutoff point varying according to education level (AEL) was used to screen subjects for CI.

RESULTS

Among these subjects, the mean age was 70.6 years (SD = 6.6) and ranged from 60 to 92 years and included 1010 (36.0%) men and 1799 (64.0%) women. The mean age was 70.7 years (SD = 6.4) for men and 70.5 years (SD = 6.7) for women. Of the 2809 subjects, 2010 (71.5%) had no formal education, 607 (21.6%) completed 1-6 years of education, and 173 (6.2%) completed more than 6 years of school education. The prevalence of CI was 35.6% (95% CI: 33.8-37.4) for both genders when the cutoff point of 23/24 was used. However, when the cutoff point was altered with respect to different education levels, the prevalence of CI was 7.0%. For each item of the CMMSE, increased years of education correlated with a higher item score, with the exception of the 'Naming' item score.

CONCLUSIONS

This study demonstrates that screening of CI using the AEL cutoff scores is feasible in a low-education population. Determining whether the 23/24 cutoff point is suitable for the Chinese people requires future prospective studies in a large Chinese population.

An epidemiological study of Alzheimer's disease in elderly Mongolian and Han populations living in rural areas of Inner Mongolia

BACKGROUND AND AIMS

This study investigated the current status and distribution of Alzheimer's disease (AD) among Mongolian and Han individuals who were at least 55 years old and living in rural areas of Inner Mongolia. This study sought to provide basic epidemiological data to better understand and treat Alzheimer's disease.

METHODS

Individuals with AD who were at least 55 old and living in one of 27 communities and two settlements in Mongolia, took part in an AD epidemiological survey from June 2008 to June 2009. Stratified, multistage random-cluster sampling was used to analyze data. The first level of random-cluster sampling consisted of data collected from questionnaires and home-visit interviews of individuals living in four Qi (a county level administration region in Mongolia) and in one city in the Xilin Guole League. Data from individuals in four district offices and ten towns from the first level random-cluster formed the second level of random-cluster sampling.

RESULTS

The final sample for this epidemiological investigation consisted of 9266 individuals. Analyses revealed that the prevalence rate of AD was 4.79% (SD=4.71%) in the combined Mongolian and Han populations of individuals at least 55 years old and living in rural areas of Inner Mongolia. The individual AD prevalence rates in the Mongolian and Han populations were 4.63% (SD=4.84%) and 4.89% (SD=4.60%), respectively. The AD prevalence rate for women was higher than for men (p<0.05). The AD prevalence rate for individuals aged 65 and older in the two combined populations was 8.06% (SD=8.55%); the rate in the Mongolian population was 7.81% (SD=8.38%) and 8.18% (SD=8.57%) in the Han population. Gender and age were risk factors for the development of AD (p<0.05) in both populations.

CONCLUSIONS

1) There was no significant difference in the AD prevalence rate between the Mongolian and Han populations consisting of individuals aged 55 and older, living in rural areas of Inner Mongolia. However, the AD prevalence rates in these populations were higher than the national average. 2) Gender and age were risk factors for the development of AD in the Mongolian and Han populations.

Can the New Cooperative Medical Scheme promote rural elders' access to health-care services?

The aim of the present study was to examine the impact of the New Cooperative Medical Scheme (NCMS) on rural elders' access to health-care services. Articles were identified from PubMed, Elsevier, Wiley, EBSCO, EMBASE, SCI Expanded, ProQuest, Google, and CNKI which is the most informative database in Chinese, with the search terms "rural", "China", "old", "older", or "elder", "elderly", or "aged", "aging", "medical insurance", or "community-based medical insurance", or "cooperative medical scheme". Related websites and yearbooks were searched as well. The NCMS has improved the health-care utilization of rural elders, and they have the highest satisfaction with it among all age groups. However, affordability difficulty remained the common barrier for the rural elderly to access quality health care, in spite of the special considerations given to the rural elderly, such as premium remission and free check-ups. Faced with ever-growing health challenges, some impoverished rural elders with poor physical health and functional limitations may lack sufficient access to basic health-care services. Followed by the provider payment reform initiated by the NCMS, a stricter regulation for doctors' prescriptions, clinical practice and disease management is needed to promote rural elders' access to health-care services. Health management for rural elders can be expected for the NCMS to promote rural elders' health-care access once a better coordination between the NCMS and health-care system can be achieved.

The Mini Mental State Examination: Review of cutoff points adjusted for schooling in a large Southern Brazilian sample

The increase in life expectancy can influence the prevalence of dementias in the population. Instruments that evaluate cognitive functions such as the Mini Mental State Examination (MMSE) are necessary for the investigation of dementia. The supposition that patient score on the MMSE can be influenced by academic level points to the need for establishing cut-off values that take into account educational level. The aim of this study was to review MMSE cut-off values adjusted for schooling in a large southern Brazilian sample.

Method

Demographic data and MMSE scores of 968 subjects, of which 162 were dementia patients and 806 healthy participants, were analyzed. The sample was grouped according to education. The cut-off values were established by ROC Curve analysis.

Results

The total sample mean age was 70.6±7.3 years, and the mean years of education was 7.2±5.3. The cut-off score of 23 points (sensitivity=86%, specificity=83%) was observed as the optimal level to detect dementia on the MMSE instrument for the overall sample. Regarding level of schooling, the cut-off values were: 21 for the illiterate group (sensitivity=93%, specificity=82%), 22 for the low education group (sensitivity=87%, specificity=82%), 23 for the middle education group (sensitivity=86%, specificity=87%) and 24 for the high education group (sensitivity=81%, specificity=87%).

Conclusions

The cut-off values revealed by this analysis, and adjusted for level of schooling, can improve the clinical evaluation of cognitive deficits.

Individual capital and cognitive ageing in Guatemala

Using data from adults 50 years and older in Guatemala (N = 643), we assessed to what extent measures of individual capital-economic, social, intellectual, and biological-were associated with and account for variation in cognitive functioning, as measured by the Modified Mini-Mental Status Exam (M-MMSE). Measures of these components of individual capital are positively associated with cognitive functioning, and together with other attributes, account for 29.6 per cent of its variance. Schooling accounts for the largest unique share (5.3 per cent) of the variance, followed by household standard of living (2.0 per cent), church attendance (1.3 per cent), and z-score for height (0.9 per cent). In a setting like Guatemala-with low schooling, widespread poverty, malnutrition, and infectious disease-early life investments that increase schooling and improve nutrition may be valuable as investments to mitigate cognitive impairment in older adults and its contribution to the disease burden.

Severity of medial temporal atrophy and amnestic mild cognitive impairment: selecting type and number of memory tests

OBJECTIVE

Medial temporal lobe atrophy (MTA) can be used as a biomarker of pathology that affects mechanisms of episodic memory. The authors compared the strength of this biomarker with performance on four memory measures and examined the influence of demographic factors including age, level of education, and primary language (English or Spanish).

METHODS

The Hopkins Verbal Learning Test-revised, Fuld Object Memory Evaluation (FOME), delayed memory for a story passage, and delayed visual reproduction of the Wechsler Memory Scale-revised tests were administered to 281 subjects who were diagnosed as having no cognitive impairment, mild cognitive impairment (MCI), impaired non-MCI, or dementia. MTA scores were obtained from visual ratings of the hippocampus, entorhinal cortex, and perirhinal cortex on coronal magnetic resonance imaging scans using a magnetization-prepared rapid gradient echo protocol.

RESULTS

Age was associated with scores on all memory measures and MTA. Level of educational attainment had no influence on FOME performance but had greater associations with scores on other memory measures. In regression models, FOME scores had the strongest relationship with MTA scores, accounting for 31% of the explained variability. Among subjects with MCI, an index representing the total number of memory tests that were impaired was also predictive of the severity of MTA scores.

CONCLUSION

Among four common tests of memory, the FOME was highly associated with MTA, and it exhibited minimal influences of education. Impairment on more than one memory test was more predictive of MTA than impairment on a single memory test.

Limitations of the Mini-Mental State Examination for screening dementia in a community with low socioeconomic status: results from the Sao Paulo Ageing & Health Study

BACKGROUND

The Mini-Mental State Examination (MMSE) is the most widely used instrument for the screening of cognitive impairment worldwide, but its ability to produce valid estimates of dementia in populations of low socioeconomic status and minimal literacy skills has not been adequately established. The authors investigated the psychometric properties of the MMSE in a community-based sample of older Brazilians.

METHOD

Cross-sectional one-phase population-based study of all residents of pre-defined areas of the city of Sao Paulo, aged 65 years or over. The Brazilian version of the MMSE was compared with DSM-IV diagnosis of dementia assessed with a harmonized one-phase procedure developed by the 10/66 Dementia Research Group.

RESULTS

Analyses were performed with 1,933 participants of the SPAH study. Receiver operating characteristic analysis showed that the MMSE cut-point of 14/15 was associated with 78.7% sensitivity and 77.8% specificity for the diagnosis of dementia amongst participants with no formal education, and the cut-point 17/18 with 91.9% sensitivity and 89.5% specificity for those with at least 1 year of formal education (areas under the curves 0.87 and 0.94, respectively; P = 0.03). Even with these best fitting cut-points, the MMSE estimate of the prevalence of dementia was four times higher than determined by the DSM-IV criteria. Education, age, sex and income influenced MMSE scores, independently of dementia caseness.

CONCLUSION

The MMSE is an adequate tool for screening dementia in older adults with minimum literacy skills, but misclassification is unacceptably high for older adults who are illiterate, which has serious consequences for research and clinical practice in low and middle income countries, where the proportion of illiteracy among older adults is high.

[Prevalence of dementia in institutionalized patients. The RESYDEM study]

INTRODUCTION

To determine the prevalence of dementia in nursing homes in Spain and to analyze the associated factors in an elderly population in the institutional setting.

MATERIAL AND METHODS

We performed a multicenter, cross-sectional, observational study of 852 residents of public, private and state-assisted nursing homes throughout Spain. Dementia was diagnosed according to the DSM-IV-TR clinical criteria. The Hughes Clinical Dementia Rating scale was used to measure global impairment or the global severity of dementia. Sociodemographic, clinical and neuropsychological variables, together with the pharmacological treatments prescribed to the participants, were recorded.

RESULTS

The overall prevalence of dementia was 61.7% (95% CI 58.4-65.1) and that of Alzheimer's disease was 16.9% (95% CI 14.3-19.5). Vascular dementia was found in 7.3% (95% CI 5.5-9.1). Female sex was independently associated with a greater frequency of dementia. The prevalence of dementia increased with age. Only 18.8% (95% CI 15.4-22.3) of the patients diagnosed with dementia received specific treatment for the disorder.

CONCLUSIONS

Two-thirds of the elderly persons living in nursing homes in Spain have dementia. Undertreatment of this disease is common. Increased awareness among health care professionals is important for the early diagnosis and appropriate management of dementia, which would represent a radical change in the approach to this disease.

Gender, resources across the life course, and cognitive functioning in Egypt

In this article, I evaluate the life-course determinants of cognitive functioning among 1,003 women and men aged 50 and older in Ismailia, Egypt. Three questions motivate this analysis: (1) Do older women have poorer cognitive functioning than do older men?; (2) Do cognitive resources accrued in childhood and adulthood have net positive associations with later-life cognitive functioning for women and men?; and (3) To what extent do differences in the amounts and effects of women's and men's cognitive resources account for gaps in their cognitive functioning? Compared with men, women have lower Modified-Mini Mental Status Exam (M-MMSE) scores for overall cognitive functioning. Cognitive resources in childhood and adulthood are jointly associated with the M-MMSE score. About 83% of the gender gap in mean M-MMSE scores is attributable to gaps in men's and women's attributes across the life course. Gender gaps in childhood cognitive resources-and especially schooling attainment-account for the largest share (18%) of the residual gender gap in cognitive functioning.

Risk-reducing effect of education in Alzheimer's disease

OBJECTIVE

To estimate the effect of education on the risk of Alzheimer's disease (AD).

METHODS

373 patients diagnosed with AD and 559 healthy control individuals without first degree relatives with known dementia, were included in a case-control study (2003-2006). All individuals were genotyped for APOE alleles. Odds ratio (OR) for developing AD was calculated by binary logistic regression, with the number of APOE epsilon 4 alleles and educational level as covariates. Analyses were carried out separately for men and women and for different age groups.

RESULTS

Carriers of one APOE epsilon 4 allele had OR of 4.2, and carriers of two APOE epsilon 4 alleles OR of 12.4 for developing AD. When adjusted for the number of APOE epsilon 4 alleles, OR for developing AD was significantly reduced in participants with 8-9 years of education compared to those with only 6-7 years, and was reduced further for those with 10-18 years of education. These findings were obtained for all the age groups studied and for both men and women.

CONCLUSIONS

Education had a consistently protective effect on the risk of developing clinical AD in a dose-dependent manner in both men and women, and in all age groups, also when adjusting for the number of APOE epsilon 4 alleles. Male gender was protective, probably at least in part because of a higher educational level.

Illiteracy and the incidence of Alzheimer's disease in the Yonchon County survey, Korea

BACKGROUND

This study aims to establish the incidence rates of Alzheimer's disease (AD) and to understand the relations between illiteracy and AD in the Korean Yonchon survey cohort.

METHODS

A community-based, dementia-free cohort of 966 people aged 65 years and older was followed up for an average of 5.4 +/- 1.60 years to detect incident AD cases using a two-phase procedure. Age-specific incidence rates were calculated using a person-years approach with Poisson distribution confidence intervals. Data were analyzed using the Cox proportional hazards model to find the hazard ratio of illiteracy.

RESULTS

The participating percentage of the survivors was 86.4% and 74 subjects were diagnosed with AD. Incidence rates per 1000 person-years were 20.99 (95% CI 16.48 to 26.35) for AD. The hazard ratio of illiteracy was 1.78 (95% CI 1.08 to 2.93) adjusted for age, sex, educational level. AD developed more rapidly with aging in the illiterate group than in the literate group.

CONCLUSIONS

Illiteracy is associated with a higher risk of AD and the risk increases with age.

Prevalence of dementia in Latin America, India, and China: a population-based cross-sectional survey

BACKGROUND

Studies have suggested that the prevalence of dementia is lower in developing than in developed regions. We investigated the prevalence and severity of dementia in sites in low-income and middle-income countries according to two definitions of dementia diagnosis.

METHODS

We undertook one-phase cross-sectional surveys of all residents aged 65 years and older (n=14 960) in 11 sites in seven low-income and middle-income countries (China, India, Cuba, Dominican Republic, Venezuela, Mexico, and Peru). Dementia diagnosis was made according to the culturally and educationally sensitive 10/66 dementia diagnostic algorithm, which had been prevalidated in 25 Latin American, Asian, and African centres; and by computerised application of the dementia criterion from the Diagnostic and Statistical Manual of Mental Disorders (DSM IV). We also compared prevalence of DSM-IV dementia in each of the study sites with that from estimates in European studies.

FINDINGS

The prevalence of DSM-IV dementia varied widely, from 0.3% (95% CI 0.1-0.5) in rural India to 6.3% (5.0-7.7) in Cuba. After standardisation for age and sex, DSM-IV prevalence in urban Latin American sites was four-fifths of that in Europe (standardised morbidity ratio 80 [95% CI 70-91]), but in China the prevalence was only half (56 [32-91] in rural China), and in India and rural Latin America a quarter or less of the European prevalence (18 [5-34] in rural India). 10/66 dementia prevalence was higher than that of DSM-IV dementia, and more consistent across sites, varying between 5.6% (95% CI 4.2-7.0) in rural China and 11.7% (10.3-13.1) in the Dominican Republic. The validity of the 847 of 1345 cases of 10/66 dementia not confirmed by DSM-IV was supported by high levels of associated disability (mean WHO Disability Assessment Schedule II score 33.7 [SD 28.6]).

INTERPRETATION

As compared with the 10/66 dementia algorithm, the DSM-IV dementia criterion might underestimate dementia prevalence, especially in regions with low awareness of this emerging public-health problem.