Low education is a genuine risk factor for accelerated memory decline and dementia

Prevalence and associated factors of neurocognitive disorder among people living with HIV/AIDS in the South Gondar zone primary hospitals, North-West Ethiopia: an institution-based cross-sectional study

OBJECTIVE

To assess the prevalence and associated factors of neurocognitive disorder among people living with HIV/AIDS in South Gondar primary hospitals, North-West Ethiopia, 2023.

DESIGN

Institution-based cross-sectional study design.

SETTING

South Gondar primary hospitals, North-West Ethiopia.

PARTICIPANTS

608 participants were recruited using the systematic random sampling technique.

MEASUREMENT

Data were collected using an interviewer-administered questionnaire and medical chart reviews. The International HIV Dementia Scale was used to screen for neurocognitive disorder. The data were entered through EPI-DATA V.4.6 and exported to SPSS V.21 statistical software for analysis. In the bivariable logistic regression analyses, variables with a value of p<0.25 were entered into a multivariable logistic regression analysis to identify factors independently associated with neurocognitive disorder. Statistical significance was declared at a value of p<0.05.

RESULTS

The prevalence of neurocognitive disorder among HIV-positive participants was 39.1%. In multivariable logistic regression, lower level of education (adjusted OR (AOR)=2.94; 95% CI 1.29 to 6.82), unemployment (AOR=2.74; 95% CI 1.29 to 6.84) and comorbid medical illness (AOR=1.80; 95% CI 1.03 to 3.14) were significantly associated with neurocognitive disorder.

CONCLUSION

HIV-associated neurocognitive problems affected over a third of the participants. According to the current study, comorbid medical conditions, unemployment and low educational attainment are associated with an increased risk of neurocognitive disorder. Therefore, early detection and treatment are essential.

Toward digitally screening and profiling AD: A GAMLSS approach of MemTrax in China

PURPOSES

To establish a normative range of MemTrax (MTx) metrics in the Chinese population.

METHODS

The correct response percentage (MTx-%C) and mean response time (MTx-RT) were obtained and the composite scores (MTx-Cp) calculated. Generalized additive models for location, shape and scale (GAMLSS) were applied to create percentile curves and evaluate goodness of fit, and the speed-accuracy trade-off was investigated.

RESULTS

26,633 subjects, including 13,771 (51.71%) men participated in this study. Age- and education-specific percentiles of the metrics were generated. Q tests and worm plots indicated adequate fit for models of MTx-RT and MTx-Cp. Models of MTx-%C for the low and intermediate education fit acceptably, but not well enough for a high level of education. A significant speed-accuracy trade-off was observed for MTx-%C from 72 to 94.

CONCLUSIONS

GAMLSS is a reliable method to generate smoothed age- and education-specific percentile curves of MTx metrics, which may be adopted for mass screening and follow-ups addressing Alzheimer's disease or other cognitive diseases.

HIGHLIGHTS

GAMLSS was applied to establish nonlinear percentile curves of cognitive decline. Subjects with a high level of education demonstrate a later onset and slower decline of cognition. Speed-accuracy trade-off effects were observed in a subgroup with moderate accuracy. MemTrax can be used as a mass-screen instrument for active cognition health management advice.

Effects of adverse childhood health experiences on cognitive function in Chinese middle-aged and older adults: mediating role of depression

BACKGROUND

Adverse childhood experiences are critical factors in depression and cognitive decrease, but the effect of adverse childhood health experiences (ACHEs) on cognitive function and the role of depression have not been fully studied.

METHODS

Data were taken from the China Health and Retirement Longitudinal Study (CHARLS) of 2014 and 2018. This study used indicators of situational memory ability and mental status to measure cognitive capacity. Besides analyzing the different types of ACHEs, scores for ACHEs were calculated to represent the severity of ACHEs. The Center for Epidemiologic Studies Depression Scale (CES-D) was used to assess depression. The analysis of this study employed two different analytical strategies in order to examine the mediated effects of depression. We used Sobel's test and Baron and Kenny's causal step approach, which utilized a generalized least squares regression model. Furthermore, a logistic regression model was used to evaluate the robustness of the Karlson-Holm-Breen (KHB) approach.

RESULTS

In this study, 6301 individuals who met the requirements of the study were included. We found that being confined to bed (ACHE3) (β=-0.3846, p = 0.022) in childhood had a negative impact on cognitive function. Similarly, ACHEs had a negative effect on cognitive function (β=-0.0819, p = 0.090). And after the depression had been introduced into the model, the regression coefficient of ACHEs on cognitive function was no longer significant (β=-0.0170, p = 0.727). The Sobel test showed that for ACHE3, the mediated proportion of the total effect of depression was 36.92%. While for ACHEs, the proportion of the mediated effect of depression was 70.11%. Finally, a robustness test of the mediating effect using the KHB method revealed that the mediating effect still existed. Further, based on different gender, age, and educational levels, the heterogeneity test indicated that the relationship between ACHEs and cognitive function and mediating effects of the depression were different as well as passing the robustness test of the interaction.

CONCLUSION

The decline in cognition had been shown to be correlated with ACHEs and depression mediated this relationship. Positive interventions might help to improve cognitive performance in individuals suffering from ACHEs and depression.

Determinants of verbal fluency trajectories among older adults from the English Longitudinal Study of Aging

BACKGROUND

Prevalence of dementia and cognitive impairment increase creating the need for identifying modifiable risk factors to reduce their burden. The aim of this study was to identify latent groups following similar trajectories in cognitive performance assessed with the verbal fluency test, as well as their determinants.

METHODS

Data from English Longitudinal Study of Aging (ELSA) were studied. Latent groups of similar course through a 6-year period in the outcome variable (verbal fluency) were investigated, along with their determinants, using Group Based Trajectory Modeling (GBTM).

RESULTS

Four latent groups of verbal fluency trajectories were revealed. Education was the strongest predictor for a favorable trajectory, while cardiovascular disease and depression symptoms were associated with lower within each trajectory.

CONCLUSION

Cardiovascular diseases and depressive symptoms are associated with a worse course of verbal fluency through aging, implying that they might serve as targets for interventions to prevent cognitive decline in the aging population. Contrarily, higher level of education is associated with a more favorable course through aging.

Determinants of Processing Speed Trajectories among Middle Aged or Older Adults, and Their Association with Chronic Illnesses: The English Longitudinal Study of Aging

The aim of this study was to identify latent groups of similar trajectories in processing speed through aging, as well as factors that are associated with these trajectories. In the context of the Ageing Trajectories of Health: Longitudinal Opportunities and Synergies (ATHLOS) project, data from the English Longitudinal Study of Aging (ELSA) (n = 12099) were analyzed. Latent groups of similar trajectories in the processing scores as well as their predictors and covariates were investigated, using group-based trajectory models (GBTM). The coefficient estimates for potential group predictors correspond to parameters of multinomial logit functions that are integrated in the model. Potential predictors included sex, level of education, marital status, level of household wealth, level of physical activity, and history of smoking, while time-varying covariates included incidence of cardiovascular disease (CVD), diabetes mellitus, depressive symptoms, and sleep disturbances. Four trajectories were identified and named after their baseline scores and shapes: High (4.4%), Middle/Stable (31.5%), Low/Stable (44.5%), and Low Decline (19.6%). Female sex, higher levels of education, mild level of physical activity, having been married, and higher level of wealth were associated with a higher probability of belonging to any of the higher groups compared to the Low/Decline that was set as reference, while presence of CVD, diabetes mellitus, and depressive symptoms were associated with lower processing speed scores within most trajectories. All the aforementioned factors might be valid targets for interventions to reduce the burden of age-related cognitive impairment.

What does (low) education mean in terms of dementia risk? A systematic review and meta-analysis highlighting inconsistency in measuring and operationalising education

Low education is considered an important modifiable risk factor for dementia worldwide, despite the lack of a formal consensus definition of low education. The primary aim of this systematic review was to document and address the inconsistency in measuring and operationalising education in dementia studies. A secondary aim was to consider the dose of education required to reduce dementia risk. The protocol was registered at PROSPERO with registration ID CRD42018096168. CINAHL, Cochrane, PsycInfo, and Pubmed databases were searched using terms related to education, dementia and/or MCI, and incidence. Studies were eligible for inclusion if a risk ratio for education and any dementia, Alzheimer's Disease (AD), Vascular Dementia (VaD) or Mild Cognitive Impairment (MCI) was reported in a population cognitively healthy at baseline. Sample sizes for 65 studies meeting selection criteria ranged from 152 to 12,881, representing populations from 24 countries. Risk of bias, assessed using a tool designed specifically for dementia risk studies, was found to be medium or low for all studies. There were 23 continuous, 29 dichotomous, and 31 categorical operationalisations of education reported. Random effects meta-analyses from continuous operationalisations suggested each year of education reduced risk by eight percent for AD (95% CI:5-12%) and seven percent for any dementia (95% CI:6-9%). Dichotomous operationalisations indicated an increased risk for low education of 45% (95% CI:29-63%) for any dementia and 85% (95% CI:56-118%) for AD, however definitions of low education were heterogeneous, ranging from zero to 12 years. There were too few studies to produce summary ratios for VaD or MCI. We conclude that, while the evidence of an association between low education and dementia incidence is robust, inconsistency in the definition, measurement and operationalisation of education hinders the translation of this evidence into practical policy recommendations to reduce dementia risk.

Investigating Predictors of Cognitive Decline Using Machine Learning

OBJECTIVES

Genetic risks for cognitive decline are not modifiable; however their relative importance compared to modifiable factors is unclear. We used machine learning to evaluate modifiable and genetic risk factors for Alzheimer's disease (AD), to predict cognitive decline.

METHODS

Health and Retirement Study participants, aged 65-90 years, with DNA and >2 cognitive evaluations, were included (n = 7,142). Predictors included age, body mass index, gender, education, APOE ε4, cardiovascular, hypertension, diabetes, stroke, neighborhood socioeconomic status (NSES), and AD risk genes. Latent class trajectory analyses of cognitive scores determined the form and number of classes. Random Forests (RF) classification investigated predictors of cognitive trajectories. Performance metrics (accuracy, sensitivity, and specificity) were reported.

RESULTS

Three classes were identified. Discriminating highest from lowest classes produced the best RF performance: accuracy = 78% (1.0%), sensitivity = 75% (1.0%), and specificity = 81% (1.0%). Top ranked predictors were education, age, gender, stroke, NSES, and diabetes, APOE ε4 carrier status, and body mass index (BMI). When discriminating high from medium classes, top predictors were education, age, gender, stroke, diabetes, NSES, and BMI. When discriminating medium from the low classes, education, NSES, age, diabetes, and stroke were top predictors.

DISCUSSION

The combination of latent trajectories and RF classification techniques suggested that nongenetic factors contribute more to cognitive decline than genetic factors. Education was the most relevant predictor for discrimination.

Lexical Relations in Spanish-Speaking Older Adults

This study analyzed the types of lexical relations produced by Spanish-speaking older adults with typical aging. A total of 120 older adults completed a word association norms task with 117 stimulus words, which allowed us to explore differences in associations by sex, age, and years of education. We employed two classifications to code the lexical relations: a traditional classification (paradigmatic versus syntagmatic) and a second classification categorizing responses into 17 types of associations (e.g., categorial versus non-categorial). Our results show that participants have a preference for paradigmatic responses (e.g., dog-animal), as well as associations with thematic-contextual co-occurrence plus semantic relations (e.g., cradle-baby). These findings suggest that older adults tend to establish lexical relations based on a combined link, one that is semantic and contextual.

Education and the moderating roles of age, sex, ethnicity and apolipoprotein epsilon 4 on the risk of cognitive impairment

BACKGROUND

We examined how the relationship between education and latelife cognitive impairment (defined as a Mini Mental State Examination score below 24) is influenced by age, sex, ethnicity, and Apolipoprotein E epsilon 4 (APOE*4).

METHODS

Participants were 30,785 dementia-free individuals aged 55-103 years, from 18 longitudinal cohort studies, with an average follow-up ranging between 2 and 10 years. Pooled hazard ratios were obtained from multilevel parametric survival analyses predicting cognitive impairment (CI) from education and its interactions with baseline age, sex, APOE*4 and ethnicity. In separate models, education was treated as continuous (years) and categorical, with participants assigned to one of four education completion levels: Incomplete Elementary; Elementary; Middle; and High School.

RESULTS

Compared to Elementary, Middle (HR = 0.645, P = 0.004) and High School (HR = 0.472, P < 0.001) education were related to reduced CI risk. The decreased risk of CI associated with Middle education weakened with older baseline age (HR = 1.029, P = 0.056) and was stronger in women than men (HR = 1.309, P = 0.001). The association between High School and lowered CI risk, however, was not moderated by sex or baseline age, but was stronger in Asians than Whites (HR = 1.047, P = 0.044), and significant among Asian (HR = 0.34, P < 0.001) and Black (HR = 0.382, P = 0.016), but not White, APOE*4 carriers.

CONCLUSION

High School completion may reduce risk of CI associated with advancing age and APOE*4. The observed ethnoregional differences in this effect are potentially due to variations in social, economic, and political outcomes associated with educational attainment, in combination with neurobiological and genetic differences, and warrant further study.

Contributions of Modifiable Risk Factors to Dementia Incidence: A Bayesian Network Analysis

OBJECTIVE

To determine and compare the contributions of modifiable risk factors (RFs) with the prevention of dementia in older adults.

DESIGN

A systematic review and Bayesian network meta-analysis (NMA). The observational group was set as a reference to collect all existing RFs and compare them with each other.

SETTING AND PARTICIPANTS

An exhaustive and comprehensive literature search strategy was used to identify relevant prospective cohort studies from several online databases from their inception to May 1, 2019. Participants without dementia were adults aged greater than 50 years.

MEASURES

The required data were extracted from the eligible studies to facilitate the Bayesian NMA.

RESULTS

Forty-three cohort studies with 277,294 participants were included in this NMA. Using the observation group as the reference, all defined RFs, except for antioxidants, were associated with lower risks of all-cause dementia [no sleep disturbances (odds ratio, OR 0.43, 95% credible interval, CrI 0.24-0.62), a high level of education (OR 0.50, 95% CrI 0.34-0.66), no history of diabetes (OR 0.57, 95% CrI 0.36-0.78), nonobese patients (OR 0.61, 95% CrI 0.39-0.83), no smoking history (OR 0.62, 95% CrI 0.45-0.79), living with family members (OR 0.67, 95% CrI 0.45-0.89), participation in physical exercise (OR 0.73, 95% CrI 0.46-0.94), abstinence from drinking (OR 0.78, 95% CrI 0.56-0.99), and no history of hypertension (OR 0.80, 95% CrI 0.65-0.96)].

CONCLUSIONS/RELEVANCE

The findings provide reliable support for the hypothesis that modifiable somatic and lifestyle factors are strong predictors of all-cause dementia.

Proteinuria and Reduced Estimated Glomerular Filtration Rate are Independently Associated With Lower Cognitive Abilities in Apparently Healthy Community-Dwelling Elderly Men in Japan: A Cross-sectional Study

BACKGROUND

The association of proteinuria and reduced estimated glomerular filtration rate (eGFR) with cognition needs more clarification. We cross-sectionally examined whether proteinuria and reduced eGFR, even in moderate stages, were independently associated with lower cognition in a community-based sample of elderly men.

METHODS

Our cohort initially comprised 1,094 men aged 40-79 years from a random sample from Shiga, Japan in 2006-2008. Of 853 men who returned for the follow-up examination (2009-2014), we analyzed 561 who were ≥65 years, free of stroke, and completed the Cognitive Abilities Screening Instrument (CASI) at follow-up (higher CASI scores [range 0 to 100] indicate better cognition). Proteinuria was assessed via dipstick. eGFR was calculated according to the Chronic Kidney Disease Epidemiology Collaboration Equation. Participants were divided into three groups either by eGFR (≥60, 59-40, and <40 mL/min/1.73 m2) or by proteinuria (no, trace, and positive), considered normal, moderate, and advanced, respectively. Using linear regression, we computed mean CASI score, with simultaneous adjustment for proteinuria and eGFR in addition to other potential confounders.

RESULTS

Significant trends of lower cognition were observed across the groups of worse proteinuria and lower eGFR independently: multivariable-adjusted mean CASI scores were 90.1, 89.3, and 88.4 for proteinuria (Ptrend = 0.029), and 90.0, 88.5, and 88.5 for eGFR (Ptrend = 0.015) in mutual-adjustment model.

CONCLUSIONS

Proteinuria and reduced eGFR, even in their moderate stages, were independently associated with lower cognition in a community-based sample of elderly men. The results suggest the importance of proteinuria and low eGFR for early detection and prevention of cognitive decline.

Education, Activity Engagement, and Cognitive Function in US Chinese Older Adults

OBJECTIVES

To examine whether and how early-life experiences such as years of schooling affect late-life cognitive function through a pathway of activity engagement.

DESIGN

Prospective.

SETTING

We used data from 2 waves of the Population Study of Chinese Elderly in Chicago (PINE).

PARTICIPANTS

PINE is the largest population-based epidemiological study of Chinese-American adults aged 60 and older in the greater Chicago area. Wave 1 data were collected for 2 years, from July 2011 to June 2013, and Wave 2 data were collected from 2013 to 2015; total sample size was 2,713.

MEASUREMENTS

Education was measured in years of schooling. Activity engagement was assessed using 15 items grouped into two clusters: cognitive activity and social activity. Cognitive function was evaluated using five instruments to assess general mental status (Chinese Mini-Mental State Examination (C-MMSE)), episodic memory, perceptual speed, working memory, global cognition score.

RESULTS

Adjusting for sociodemographic and health-related control variables, education measured at Wave 1 was associated with better global cognition (b = 0.025, p < .001), C-MMSE (b = .037, p < .001), episodic memory (b = .026, p < .001), Symbol Digit Modalities Test perceptual speed (b = .036, p < .001), and Digit Span Backward working memory (b = .047, p < .001) at Wave 2. Activity engagement, cognitive activity in particular, significantly mediates the effect of education on all cognitive tests, with the size of the mediating effect ranging from 16% to approximately 24%.

CONCLUSION

Amount of schooling early in life is significantly related to late-life cognitive function in virtually all domains, and cognitive activity is one of many links between the two. J Am Geriatr Soc 67:S525-S531, 2019.

The relation between teeth loss and cognitive decline among Saudi population in the city of Riyadh: A pilot study

Background

Teeth are necessary for sensory input to the brain during the chewing process, but how the decrease in this sensory input, due to loss of teeth, may cause weak memory and lead to cognitive decline is not well understood. This pilot public survey aiming to assess the correlation between the number of missing teeth, periodontal disease, and cognitive skill in the city of Riyadh.

Material& Methods

A multicenter cross-sectional survey, targeting geriatric population aged ≥60 years, was performed in Riyadh City, Saudi Arabia. The Montreal Cognitive Assessment (MoCA) was conducted to all participants to assess their cognitive function. Assessment of oral health status was carried out, including the number of present dentation and their periodontal status. Community periodontal-index (CPI) was used to assess the periodontal condition. The primary variables were number of missing teeth, periodontal disease and MoCA test scores. Chi-square test and Pearson’s correlation coefficients were computed and the significant P- value was set at <0.05.

Results

Of 95 participants, overall, 57 (60%) and 38 (40%) were male and female, respectively, with a mean age of 65.67 ± 6.32 years. Females showed more significant cognitive decline than males (P < 0.001). Cognitive decline was significantly high in participants with low educational level 19 (95%), unemployment 41 (79%), and lower income people 26 (79%), while being cognitive intact was significantly higher in highly educated 13 (87%), retired 21 (62%), and higher income people 28 (74%) at (P < 0.001). An advanced age and greater number of missing teeth are associated with lower MoCA test scores. No statistical significant correlation with regard to periodontal disease and MoCA test scores.

Conclusion

Based on the preliminary data, positive correlation was confirmed when the number of missing teeth and cognitive skill were assessed. Therefore, larger, multi-center regional surveys are needed to investigate further this relationship.

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

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

Alzheimer's Disease Mortality according to Socioeconomic Factors: Country Study

Aim of the paper is to quantify effects of socioeconomic factors on Alzheimer's Disease Mortality in the Slovak Republic. We applied potential gains in life expectancy (PGLE) method to measure the impact of elimination of Alzheimer's disease on life expectance in Slovak regions. PGLE is based on life table adjustment according to elimination of mortality caused by specific diagnosis. Our dataset consists of all deceased from Slovak Republic from 2001 to 2015. We analyse the impact of unemployment rate, GDP per capita, average wage, and education on life expectance in Slovak regions. To estimate that impact, ordinary least squares (OLS) is applied. According to our model, gross domestic product, average wage, and education influence mortality caused by Alzheimer's disease.

Awareness and understanding of dementia in South Asians: A synthesis of qualitative evidence

Background

Despite a growing elderly South Asian population, little is known about the experience of diagnosis and care for those living with dementia. There have been a number of individual qualitative studies exploring the experiences of South Asian people living with dementia and their carers across different contexts. There has also been a growing interest in synthesizing qualitative research to systematically integrate qualitative evidence from multiple studies to tell us more about a topic at a more abstract level than single studies alone. The aim of this qualitative synthesis was to clearly identify the gaps in the literature and produce new insights regarding the knowledge and understanding of the attitudes, perceptions, and beliefs of the South Asian community about dementia.

Methods

Following a systematic search of the literature, included qualitative studies were assessed by two independent reviewers for methodological quality. Data were extracted and pooled using the Joanna Briggs Institute Qualitative Assessment and Review Instrument (QARI). Findings were synthesized using the Joanna Briggs Institute approach to qualitative synthesis by meta-aggregation.

Results

Seventeen papers were critically appraised, with 13 meeting the inclusion criteria. Participants were mostly of South Asians of Indian background; followed by Pakistani with a few Sri Lankans. Missing South Asian countries from the current evidence base included those from Bangladesh, Bhutan, Maldives, and Nepal. Three meta-synthesis themes emerged from the analysis: (1) a poor awareness and understanding of dementia, (2) the experience of caregiving, and (3) the attitudes toward dementia care provision.

Conclusions

A consistent message from this qualitative synthesis was the limited knowledge and understanding of dementia amongst the South Asians. Whilst symptoms of dementia such as ‘memory loss’ were believed to be a part of a normal ageing process, some South Asian carers viewed dementia as demons or God’s punishments. Most studies reported that many South Asians were explicit in associating stigmas with dementia.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Total Sleep Time Interacts With Age to Predict Cognitive Performance Among Adults

STUDY OBJECTIVES

To investigate interactions between high and low amounts of sleep and other predictors of cognitive performance.

METHODS

We used four cognitive tests to determine whether sleep time interacted with age, personal history of a memory problem, parental history of a memory problem, or personal concerns about memory and were associated with cognitive performance. Data were collected from an internet-based cohort study. We used an ordinary least squares regression with restricted cubic splines, controlling for demographic variables and comorbidities.

RESULTS

We found significant nonlinear interactions between (1) total sleep time and age and (2) total sleep time and personal history of a memory problem and cognitive performance. Short and long sleep durations and self-reported memory complaints were associated with poorer performance on a test of attention and this was true to a greater degree in younger and older adults. A repeat analysis excluding subjects reporting dementia was significant only for the test of attention.

CONCLUSIONS

These results extend existing data on sleep duration and cognition across the lifespan by combining in a single study the results from four specific cognitive tests, both younger and older adults, and four self-reported risk factors for cognitive impairment. Longitudinal studies with biomarkers should be undertaken to determine whether causal mechanisms, such as inflammation or amyloid buildup, account for these associations.

The development of patient information leaflets incorporating patient diversity considerations: Varicocele embolisation and fluoroscopy guided joint injection examinations

PURPOSE

The production of patient information leaflets (PILs) for diverse patient cohorts is challenging. This study developed varicocele and fluoroscopy guided joint injection (FLGJI) procedural PILs.

METHODOLOGY

Evidence-based PILs were developed, providing radiological procedural information - preparation, explanation of interventional procedures and aftercare. PIL readability was tested via validated readability programs: Flesch Kincaid and Flesch ease reading score methods. Radiology approval of PIL(s) content was confirmed. PILs were distributed with appointment information. Patient interviews were conducted just prior to examination and by telephone, 7 days post procedure.

RESULTS

Participants were purposely sampled (6 months): varicocele embolisation (n = 17) and FLGJI (n = 47). Overall 78.1% of all participants preferred Maltese leaflets. Varicocele embolisation patients were generally younger and a greater percentage educated to tertiary level compared to FLGJI patients. Education and age were found to be recurrent significant variables in the patient demographics and responses for both patient cohorts. Age versus education for the FLGJI cohort proved to be significant for several responses. Readability statistics identified the FLGJI leaflet as a plain English rating, the varicocele embolisation leaflet was more difficult. Patient feedback identified 'what is a varicocele?' as important to varicocele embolisation patients whereas FLGJI patients chose, 'advice about aftercare' and 'advice about pain management', highlighting differences in patients' priorities between procedures.

CONCLUSION

PILs provided tangible, accurate information pre and post examination. Patient involvement in achieving appropriate information informed the PILs development, which were adopted clinically. The development of tailored PILs to meet the diversity of other interventional radiology procedures is recommended.

Acceptability and Results of Dementia Screening Among Older Adults in the United States

OBJECTIVES

To measure older adults acceptability of dementia screening and assess screening test results of a racially diverse sample of older primary care patients in the United States.

DESIGN

Cross-sectional study of primary care patients aged 65 and older.

SETTING

Urban and suburban primary care clinics in Indianapolis, Indiana, in 2008 to 2009.

PARTICIPANTS

Nine hundred fifty-four primary care patients without a documented diagnosis of dementia.

MEASUREMENTS

Community Screening Instrument for Dementia, the Mini-Mental State Examination, and the Telephone Instrument for Cognitive Screening.

RESULTS

Of the 954 study participants who consented to participate, 748 agreed to be screened for dementia and 206 refused screening. The overall response rate was 78.4%. The positive screen rate of the sample who agreed to screening was 10.2%. After adjusting for demographic differences the following characteristics were still associated with increased likelihood of screening positive for dementia: age, male sex, and lower education. Patients who believed that they had more memory problems than other people of their age were also more likely to screen positive for dementia.

CONCLUSION

Age and perceived problems with memory are associated with screening positive for dementia in primary care.

Factors Affecting Cognitive Impairment and Depression in the Elderly Who Live Alone: Cases in Daejeon Metropolitan City

Background and Purpose

With the rapid increase in the number of elderly people in Korea, multiple socio-economic problems have emerged. In 2015, 6.4 million people accounting for about 13% of the total population in Korea were aged 65 years and over. As the elderly population continues to grow, the elderly who live alone are also increasing. They have potential risks in medical and neuropsychological aspects. The purpose of this study was to investigate the association between cognition and socio-environmental status in the elderly who live alone.

Methods

This study was conducted on 512 people who live alone (equivalent to 1% of the total elderly people) in Daejeon Metropolitan City between April and November 2015. Structured questionnaires were used to investigate the general characteristics, socio-economic status, physical status, and mood for participants. Simple tests using Mini-Mental Status Examination-Demetia Screening, Geriatric Depression Scale and Korean-instrumental activities of daily living were also performed.

Results

Among the 512 participants, 109 participants (21.3%) had cognitive impairment, and 128 participants (25.0%) had depression. The number of daily meals, frequency of meeting with family, and depression were independent risk factors for cognitive impairment. Factors including the duration of living alone, cognitive impairment, poor self-perceived health status, frequency of meeting with family and duration of education were considered an independent risk factor for depression.

Conclusions

This study showed that the elderly who live alone are susceptible to cognitive impairment and depression, and factors including the number of daily meals, social contact, and self-perceived health status may affect cognition and depressive mood. Thus, physicians need to pay attention to management of major factors that may cause cognition impairment and depression in the elderly who live alone; in addition, they require ongoing community interest and support.

A Systematic Review of Intervention Studies Examining Nutritional and Herbal Therapies for Mild Cognitive Impairment and Dementia Using Neuroimaging Methods: Study Characteristics and Intervention Efficacy

Neuroimaging facilitates the assessment of complementary medicines (CMs) by providing a noninvasive insight into their mechanisms of action in the human brain. This is important for identifying the potential treatment options for target disease cohorts with complex pathophysiologies. The aim of this systematic review was to evaluate study characteristics, intervention efficacy, and the structural and functional neuroimaging methods used in research assessing nutritional and herbal medicines for mild cognitive impairment (MCI) and dementia. Six databases were searched for articles reporting on CMs, dementia, and neuroimaging methods. Data were extracted from 21/2,742 eligible full text articles and risk of bias was assessed. Nine studies examined people with Alzheimer's disease, 7 MCI, 4 vascular dementia, and 1 all-cause dementia. Ten studies tested herbal medicines, 8 vitamins and supplements, and 3 nootropics. Ten studies used electroencephalography (EEG), 5 structural magnetic resonance imaging (MRI), 2 functional MRI (fMRI), 3 cerebral blood flow (CBF), 1 single photon emission tomography (SPECT), and 1 positron emission tomography (PET). Four studies had a low risk of bias, with the majority consistently demonstrating inadequate reporting on randomisation, allocation concealment, blinding, and power calculations. A narrative synthesis approach was assumed due to heterogeneity in study methods, interventions, target cohorts, and quality. Eleven key recommendations are suggested to advance future work in this area.

Circadian Disruption Reveals a Correlation of an Oxidative GSH/GSSG Redox Shift with Learning and Impaired Memory in an Alzheimer's Disease Mouse Model

It is unclear whether pre-symptomatic Alzheimer's disease (AD) causes circadian disruption or whether circadian disruption accelerates AD pathogenesis. In order to examine the sensitivity of learning and memory to circadian disruption, we altered normal lighting phases by an 8 h shortening of the dark period every 3 days (jet lag) in the APPSwDI NOS2-/- model of AD (AD-Tg) at a young age (4-5 months), when memory is not yet affected compared to non-transgenic (non-Tg) mice. Analysis of activity in 12-12 h lighting or constant darkness showed only minor differences between AD-Tg and non-Tg mice. Jet lag greatly reduced activity in both genotypes during the normal dark time. Learning on the Morris water maze was significantly impaired only in the AD-Tg mice exposed to jet lag. However, memory 3 days after training was impaired in both genotypes. Jet lag caused a decrease of glutathione (GSH) levels that tended to be more pronounced in AD-Tg than in non-Tg brains and an associated increase in NADH levels in both genotypes. Lower brain GSH levels after jet lag correlated with poor performance on the maze. These data indicate that the combination of the environmental stress of circadian disruption together with latent stress of the mutant amyloid and NOS2 knockout contributes to cognitive deficits that correlate with lower GSH levels.

Education is associated with sub-regions of the hippocampus and the amygdala vulnerable to neuropathologies of Alzheimer's disease

We evaluated the correlation of educational attainment with structural volume and shape morphometry of the bilateral hippocampi and amygdalae in a sample of 110 non-demented, older adults at elevated sociodemographic risk for cognitive and functional declines. In both men and women, no significant education-volume correlation was detected for either structure. However, when performing shape analysis, we observed regionally specific associations with education after adjusting for age, intracranial volume, and race. By sub-dividing the hippocampus and the amygdala into compatible subregions, we found that education was positively associated with size variations in the CA1 and subiculum subregions of the hippocampus and the basolateral subregion of the amygdala (p < 0.05). In addition, we detected a greater left versus right asymmetric pattern in the shape-education correlation for the hippocampus but not the amygdala. This asymmetric association was largely observed in men versus women. These findings suggest that education in youth may exert direct and indirect influences on brain reserve in regions that are most vulnerable to the neuropathologies of aging, dementia, and specifically, Alzheimer disease.

The Edinburgh Cognitive and Behavioural ALS Screen in a Chinese Amyotrophic Lateral Sclerosis Population

Objective

The existing screening batteries assessing multiple neuropsychological functions are not specific to amyotrophic lateral sclerosis (ALS) patients and are limited to their physical dysfunctions, whereas category cognitive tests are too time-consuming to assess all the domains. The Edinburgh Cognitive and Behavioural ALS Screen (ECAS) was recently developed as a fast and easy cognitive screening tool specifically designed for patients. The purpose of the study was to validate the effectiveness of the Chinese version in Chinese ALS populations.

Methods

Eighty-four ALS patients and 84 age-, gender- and education-matched healthy controls were included in this cross-sectional study. All the participants took the ECAS, Mini-Mental State Examination (MMSE) and Frontal Assessment Battery (FAB). Primary caregivers of patients were interviewed for behavioural and psychiatric changes.

Results

Significant differences were noted in language (p = 0.01), fluency, executive function, ALS-specific functions, and ECAS total score (p<0.01) between ALS patients and controls. The cut-off value of the total ECAS score was 81.92. Cognitive impairment was observed in 35.71% of patients, and 27.38% exhibited behavioural abnormalities. The ECAS total score had a medium correlation with education year. Memory was more easily impaired in the lower education group, whereas verbal fluency and language function tended to be preserved in the higher education group. The average time of ECAS was only 18 minutes.

Conclusion

The Chinese version of the ECAS is the first screening battery assessing multiple neuropsychological functions specially designed for the ALS population in China, which provides an effective and rapid tool to screen cognitive and behavioural impairments.

Prevalence and correlates of cognitive asymmetry in a large sample of Alzheimer's disease patients

Previous research has suggested that a significant minority of patients with Alzheimer's disease (AD) exhibit asymmetric cognitive profiles (greater verbal than visuospatial impairment or vice versa) and that these patient subgroups may differ in demographic and other characteristics. Prior studies have been relatively small, and this investigation sought to examine correlates of asymmetry in a large patient sample (N = 438). Patients were classified into the following cognitive profile groups: low verbal, symmetric, and low visuospatial. Consistent with past research, 28.3% of participants were classified as having asymmetric cognitive profiles, with more participants in the low visuospatial subgroup. Low visuospatial participants were younger than members of the other subgroups, and low verbal participants performed worse on a measure estimating premorbid verbal intelligence. Findings regarding apolipoprotein E (ApoE) ε4 genotype were equivocal, although results provided some evidence for an effect of the ɛ4 allele on cognitive asymmetry. These results suggest systematic differences between neuropsychological asymmetry profiles that support the possibility of distinct subgroups of the disease.

Cognitive reserve and cognitive function in healthy older people: a meta-analysis

The associations between proxy measures of cognitive reserve (CR) and cognition vary across studies and cognitive domains. This meta-analysis aimed to assess the relationship between CR and cognition in multiple domains (memory, executive function, visuospatial ability, and language). CR was considered in terms of three key proxy measures - educational level, occupational status, and engagement in cognitively stimulating activities - individually and in combination. One-hundred and thirty-five studies representing 128,328 participants were included. Of these, 109 used a measure of education, 19 used a measure of occupation, 31 used a measure of participation in cognitively stimulating activities, and 6 used a combination of these. All three proxy measures had a modest positive association with cognition; occupational status and cognitive activities showed the most variation across cognitive domains. This supports the view that the commonly used proxy measures of CR share an underlying process but that each additionally provides a unique contribution to CR.

Alzheimer's disease and chronic periodontitis: is there an association?

Alzheimer's disease, an affliction of old age, is one of the leading causes for dementia worldwide. Various risk factors including family history, genetics and infections have been implicated in its pathogenesis. The cognitive decline in this condition is mainly a result of the formation of amyloid deposits that provoke neuroinflammation, ultimately resulting in cell death. Recently, an association between peripheral inflammation and Alzheimer's disease was hypothesized. It was suggested that chronic systemic inflammation worsened the inflammatory processes in the brain. This was mainly attributed to increased levels of pro-inflammatory mediators, such as interleukin-1, interleukin -6 and tumor necrosis factor-α in the plasma. As chronic periodontitis is a widespread peripheral immunoinflammatory condition, it has been proposed to play a significant role in the aggravation of Alzheimer's disease. With this background, the current review focuses on the relationship between Alzheimer's disease and chronic periodontitis, and its therapeutic implications.

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.

In-hospital acute stress symptoms are associated with impairment in cognition 1 year after intensive care unit admission

RATIONALE

Prior studies have found that cognitive dysfunction is common in intensive care unit (ICU) survivors. Yet, relatively little is known about potentially modifiable risk factors for longer-term post-ICU cognitive impairment.

OBJECTIVES

To determine if in-hospital acute stress symptoms were associated with impaired 12-month cognitive functioning among ICU survivors.

METHODS

We prospectively enrolled 150 nontrauma patients without cognitive impairment or a dementia diagnosis who were admitted to an ICU for more than 24 hours. Patients were interviewed before hospital discharge and again via telephone at 12 months post-ICU.

MEASUREMENTS AND MAIN RESULTS

Demographics and clinical information were obtained through medical record reviews and in-person interviews. In-hospital acute stress symptoms were assessed with the Posttraumatic Stress Disorder Checklist-Civilian Version. Twelve-month post-ICU cognition was assessed with the modified Telephone Interview for Cognitive Status. Follow-up interviews were completed with 120 (80%) patients. Patients' mean age at hospitalization was 48.2 years (SD, 13.7). In unadjusted analyses, a greater number of in-hospital acute stress symptoms was associated with significantly greater impairment in 12-month cognitive functioning (β, -0.1; 95% confidence interval, -0.2 to -0.004; P = 0.04). After adjusting for patient and clinical factors, in-hospital acute stress symptoms were independently associated with greater impairment in 12-month cognitive functioning (β, -0.1; 95% CI, -0.2 to -0.01; P = 0.03).

CONCLUSIONS

In-hospital acute stress symptoms may be a potentially modifiable risk factor for greater impairment in cognitive functioning post-ICU. Early interventions for at-risk ICU survivors may improve longer-term outcomes.

Individual and Area Level Socioeconomic Status and Its Association with Cognitive Function and Cognitive Impairment (Low MMSE) among Community-Dwelling Elderly in Singapore

Background/Aims

Neighborhood socioeconomic status (SES) can affect cognitive function. We assessed cognitive function and cognitive impairment among community-dwelling elderly in a multi-ethnic urban low-SES Asian neighborhood and compared them with a higher-SES neighborhood.

Methods

The study population involved all residents aged ≥60 years in two housing estates comprising owner-occupied housing (higher SES) and rental flats (low SES) in Singapore in 2012. Cognitive impairment was defined as <24 on the Mini Mental State Examination. Demographic/clinical details were collected via questionnaire. Multilevel linear regression was used to evaluate factors associated with cognitive function, while multilevel logistic regression determined predictors of cognitive impairment.

Results

Participation was 61.4% (558/909). Cognitive impairment was found in 26.2% (104/397) of residents in the low-SES community and in 16.1% (26/161) of residents in the higher-SES community. After adjusting for other sociodemographic variables, living in a low-SES community was independently associated with poorer cognitive function (β = −1.41, SD = 0.58, p < 0.01) and cognitive impairment (adjusted odds ratio 5.13, 95% CI 1.98–13.34). Among cognitively impaired elderly in the low-SES community, 96.2% (100/104) were newly detected.

Conclusion

Living in a low-SES community is independently associated with cognitive impairment in an urban Asian society.

[Epidemiology of dementia in elderly living in the 3rd borough of Bangui (Central African Republic)]

Given the gradual improvement of living conditions and aging, dementia and related syndromes are becoming serious problems in the developing countries. A cross-sectional door to door type study in neighbourhood, was conducted from October 2008 to January 2009, in the general population in Bangui, order to help get a better understanding of the prevalence and risk factors of dementia among people over 65 living in the Central African capital. Of the 496 elderly respondents, 188 had cognitive disorders. After a neuropsychological examination, 40 of these subjects were diagnosed with dementia. The prevalence of dementia was 8.1% (IC 95% = [5.7-10.5]). The average age of subjects with dementia, ranging from 65 to 90 years, was 76.0 ± 7.1 years. There was a significant risk of developing dementia for an increase of ten years old (OR = 2.6, 95% CI [1.5 to 4.5]). The sex-ratio was 6/34. 82.5% of the demented had never attended school. 70.0% showed a state of malnutrition (BMI ≤ 18,5 kg/m(2)), significantly associated with dementia (OR = 3.3; IC 95% = [1.5-7.3]). The blood pressure was high in 67.5% of demented which is significantly associated with dementia (OR = 2.4; IC 95% = [1.1-5.4]). A recent change in financial status was a factor significantly associated with dementia (OR = 6.4; IC 95% = [1.8-22.5]). These results support the existence of dementia in urban Africa. The observed prevalence is close to those found in high-income countries. Further studies should be conducted which includes both the rural and urban Africa, to better understand the problem and solutions consider to comprehensive care and prevention axes adapted to our context.

Risk factors for dementia in a senegalese elderly population aged 65 years and over

Background

With the aging of the population, dementia is increasing worldwide. The objective of this study was to identify risk factors for dementia in an elderly population utilizing a primary health care service in Dakar, Senegal.

Methods

Through a cross-sectional study conducted from March 2004 to December 31, 2005, 507 elderly patients aged ≥65 years who came to the Social and Medical Center of IPRES, Dakar, Senegal, were first screened with the screening interview questionnaire ‘Aging in Senegal’. Those who were cognitively impaired underwent a clinical examination to detect dementia. Univariate, bivariate, and multivariate logistic regression analyses were done.

Results

The whole population had a mean age of 72.4 years (±5.2) and was mostly male, married, and non-educated. Hypertension, arthritis, and gastrointestinal diseases were the main health conditions reported in the past medical history. Smoking was important while alcohol consumption was rare. Social network was high. Forty-five patients (8.87%) had dementia. In the multivariate model, only advanced age, education, epilepsy, and family history of dementia were independently associated with dementia.

Conclusion

The risk factors identified are also found in developed countries confirming their role in dementia. It is important to take dementia into consideration in Senegal and to sensitize the community for prevention.

Cognitive plasticity in normal and pathological aging

The main goal of the present study is to examine to what extent age and cognitive impairment contribute to learning performance (cognitive plasticity, cognitive modifiability, or learning potential). To address this question, participants coming from four studies (Longitudinal Study of Active Aging, age range, 55–75 years, N = 458; Longitudinal Study in the very old [90+], age range, 90–102, N = 188, and Cognitive Plasticity within the Course of Cognitive Impairment, 97 “Normal”, 57 mild cognitive impairment [MCI], and 98 Alzheimer’s disease [AD] patients) were examined through a measure of verbal learning (developed from Rey). The results show that all age, MCI, and AD groups learned across the five learning trials of that test, but significant differences were found due to age, pathology, and education. The effects of pathology (MCI and AD) can be expressed in a metric of “years of normal decline by age”; specifically, being MCI means suffering an impairment in performance that is equivalent to the decline of a normal individual during 15 years, whereas the impact of AD is equivalent to 22.7 years. Likewise, the improvement associated with about 5 years of education is equivalent to about 1 year less of normal aging. Also, the two pathological groups significantly differed from “normal” groups in the delayed trial of the test. The most dramatic difference is that between the “normal” group and the AD patients, which shows relatively poorer performance for the AD group in the delayed trial than in the first learning trial. The potential role of this unique effect for quick detection purposes of AD is assessed (in the 75–89 years age range, sensitivity and specificity equal 0.813 and 0.917, respectively).

Should Alzheimer's disease be equated with human brain ageing? A maladaptive interaction between brain evolution and senescence

In this review Alzheimer's disease is seen as a maladaptive interaction between human brain evolution and senescence. It is predicted to occur in everyone although does not necessarily lead to dementia. The pathological process is initiated in relation to a senescence mediated functional down-regulation in the posteromedial cortex (Initiation Phase). This leads to a loss of glutamatergic excitatory input to layer II entorhinal cortex neurons. A human specific maladaptive neuroplastic response is initiated in these neurons leading to neuronal dysfunction, NFT formation and death. This leads to further loss of glutamatergic excitatory input and propagation of the maladaptive response along excitatory pathways linking evolutionary progressed vulnerable neurons (Propagation Phase). Eventually neurons are affected in many brain areas resulting in dementia. Possible therapeutic approaches include enhancing glutamatergic transmission. The theory may have implications with regards to how Alzheimer's disease is classified.

Comparison between Spanish young and elderly people evaluated using Rivermead Behavioural Memory Test

The first objective of this work was to compare scores obtained in the daily memory function between young and elderly people, and to check whether there are differences between the groups for each of the profile scores obtained in the memory test. A second aim of this paper is to study the relationship between everyday memory and age, while controlling for gender and educational level. The total and profile scores obtained in the Rivermead Behavioural Memory Test were compared in a sample of 60 young and 120 elderly people from Valencia (Spain). Results showed significant differences between the two groups: those between 18 and 30 years obtained a higher average than those over 65. Once the group comparison was controlled for gender and educational level, the statistical effect of age group disappeared. The non-significant effect of group can not be explained by the introduction of gender, because both its main effect and the interaction were not statistically significant. However, educational level had a statistically significant effect which may explain the non-significant effect of group in this new analysis. The main conclusion is the need to carefully control for educational level in all studies related with everyday memory and ageing, as the differences found could be due to generational differences more than to biological deterioration.

Potentially modifiable risk factors for dementia in identical twins

BACKGROUND

The purpose of this study was to test nongenetic factors that might explain discordance for dementia in monozygotic twin pairs. Risk factors included education, engaged lifestyle in midlife, and early life circumstances indexed by tooth loss, short adult height, and parental social class.

METHODS

Data are from the HARMONY study, including members of the Swedish Twin Registry age 65 and older and alive in 1998, who were screened and assessed clinically for dementia. Analyses included a case-control design to evaluate the risk factors and a co-twin control design that permits testing nongenetic risk factors while controlling for genetic influences. Case-control analyses included 310 dementia cases and 3,063 nondemented controls. There were 106 monozygotic twin pairs discordant for dementia. Risk factors were assessed independently by the Swedish Twin Registry three decades previously.

RESULTS

Case-control findings showed that history of tooth loss before age 35 and low educational attainment were significant risk factors for Alzheimer's disease, with short adult height also contributing to risk for total dementia. In co-twin control analyses, only history of tooth loss before age 35 was a significant risk factor for Alzheimer's disease, whereas low educational attainment also contributed to risk for total dementia and lack of physical exercise to risk for non-Alzheimer's dementias.

CONCLUSIONS

Potentially modifiable risk factors from early and midlife, with a cumulative detrimental effect on the brain, contribute to risk of dementia. Based on the association with tooth loss, further investigation of inflammatory load as a risk factor for Alzheimer's disease is warranted.

The NIH Cognitive and Emotional Health Project. Report of the Critical Evaluation Study Committee

BACKGROUND

The Cognitive and Emotional Health Project (CEHP) seeks to identify the demographic, social, and biological determinants of cognitive and emotional health in the older adult. As part of the CEHP, a critical evaluation study committee was formed to assess the state of epidemiological research on demographic, social, and biological determinants of cognitive and emotional health.

METHODS

Criteria for inclusion in the survey were large cohort studies, longitudinal in design, participants predominantly 65 years or older, with measurements of both cognition and emotion, and information on a wide variety of demographic, psychosocial, and biological factors. North American and European studies, which met these criteria, were selected for the review. Outcome measures included cognition, cognitive decline, and cognitive function. For emotion, symptoms included depression and anxiety, positive and negative affect, subjective well being, mastery, and resilience.

RESULTS

Ninety-six papers were identified that addressed cognitive and emotional outcomes. A large variety of risk factors were consistently identified with cognitive outcomes, particularly those previously associated with increased risk of cardiovascular disease. There was considerable overlap between risk factors for cognitive and emotional outcomes.

CONCLUSION

This review identifies a large number of lifestyle and health behaviors that alter the risk for maintenance of cognitive and emotional health. Large longitudinal cohort studies are a unique source to explore factors associated with cognitive and emotional health. Secondary analyses of these studies should be encouraged as should the development of standardized questionnaires to measure cognitive and emotional health. Future research in this field should study cognitive and emotional health simultaneously.

Tooth loss and cognitive impairment

OBJECTIVES

Chronic subclinical inflammation may elevate the risk of cognitive impairment. Periodontitis is associated with subclinical inflammation and accounts in part for tooth loss. The hypothesis was tested that periodontitis and tooth loss as a proxy of chronic periodontitis is associated with cognitive impairment in the elderly.

SUBJECTS AND METHODS

The population-based Study of Health in Pomerania comprises 1336 subjects (60-79 years). Cognitive impairment was assessed with the Mini-Mental Status Examination (MMSE). Tobit regression analyses were adjusted for potential confounders.

RESULTS

A decreased number of teeth was associated with lower MMSE scores in females (p<0.001) and males (p=0.007) in age-adjusted models. In the fully adjusted models, tooth loss was associated with cognitive impairment in females (p=0.002) but not in males (p=0.825).

CONCLUSIONS

A significant association between tooth loss and cognitive impairment was found in females that was not accounted for by potential confounders. Former periodontitis may account for this association as periodontitis was frequently the cause for tooth extractions.

Educational attainment and cognitive decline in old age

BACKGROUND

Level of education is a well-established risk factor for Alzheimer disease but its relation to cognitive decline, the principal clinical manifestation of the disease, is uncertain.

METHODS

More than 6,000 older residents of a community on the south side of Chicago were interviewed at approximately 3-year intervals for up to 14 years. The interview included administration of four brief tests of cognitive function from which a previously established composite measure of global cognition was derived. We estimated the associations of education with baseline level of cognition and rate of cognitive change in a series of mixed-effects models.

RESULTS

In an initial analysis, higher level of education was related to higher level of cognition at baseline, but there was no linear association between education and rate of change in cognitive function. In a subsequent analysis with terms to allow for nonlinearity in education and its relation to cognitive decline, rate of cognitive decline at average or high levels of education was slightly increased during earlier years of follow-up but slightly decreased in later years in comparison to low levels of education. Findings were similar among black and white participants. Cognitive performance improved with repeated test administration, but there was no evidence that retest effects were related to education or attenuated education's association with cognitive change.

CONCLUSIONS

The results suggest that education is robustly associated with level of cognitive function but not with rate of cognitive decline and that the former association primarily accounts for education's correlation with risk of dementia in old age.

Handedness and cognitive function in older men and women: a comparison of methods

OBJECTIVE

Previous studies of handedness and cognitive function rely on self-classification and yield inconsistent results. This study examines the associations of self-reported versus grip-strength-based handedness with cognitive function in healthy older men and women.

DESIGN

Cross-sectional study.

SETTING

1988-91 follow-up clinic visit and 1991 mailed survey.

PARTICIPANTS

684 men and 985 women aged 55-95 who were community dwelling.

MEASUREMENTS

Cognitive function was assessed with 12 tests and grip strength was measured by hand-held dynamometer. Self-reported handedness was obtained with a mailed survey.

RESULTS

By self-report, 92.1% of men and women were right-handed; 2.0% were left handed. By grip strength, in men, 64.3% were right-handed, 22.5% left-handed, and 13.2% ambidextrous. In women, 61.3% were right-handed, 17.3% left-handed, and 21.4% ambidextrous. No cognitive function differences were found by self-reported handedness in either sex (p's>0.10). However, based on grip strength, left-handed women scored poorer than right-handed or ambidextrous women in immediate and delayed memory, attention, and verbal fluency (p's<0.05). Using categorical definitions, left-handed or ambidextrous individuals based on grip strength were more likely to show poor cognitive function on 4 of 5 tests.

CONCLUSION

Grip strength is a useful alternative to self-reports for classifying handedness. Left-handedness by grip-strength, may be related to poorer cognitive function; this association may vary by gender.

Item response theory facilitated cocalibrating cognitive tests and reduced bias in estimated rates of decline

OBJECTIVE

To cocalibrate the Mini-Mental State Examination, the Modified Mini-Mental State, the Cognitive Abilities Screening Instrument, and the Community Screening Instrument for Dementia using item response theory (IRT) to compare screening cut points used to identify cases of dementia from different studies, to compare measurement properties of the tests, and to explore the implications of these measurement properties on longitudinal studies of cognitive functioning over time.

STUDY DESIGN AND SETTING

We used cross-sectional data from three large (n>1000) community-based studies of cognitive functioning in the elderly. We used IRT to cocalibrate the scales and performed simulations of longitudinal studies.

RESULTS

Screening cut points varied quite widely across studies. The four tests have curvilinear scaling and varied levels of measurement precision, with more measurement error at higher levels of cognitive functioning. In longitudinal simulations, IRT scores always performed better than standard scoring, whereas a strategy to account for varying measurement precision had mixed results.

CONCLUSION

Cocalibration allows direct comparison of cognitive functioning in studies using any of these four tests. Standard scoring appears to be a poor choice for analysis of longitudinal cognitive testing data. More research is needed into the implications of varying levels of measurement precision.

The Apartment Test: validity of a memory measure

The Memory in Reality (MIR) test, or Apartment Test, was designed as an ecologically valid alternative to word list recall measures. Participants name 10 everyday objects, place them in a scale model of an apartment and after a delay with interference, recall the objects and their placement. Two studies are reported. Study 1 included 51 older adult volunteers. Study 2 was a population-based sample of 633 older twins. The Apartment Test Recall and Placement tasks were highly correlated with word list delayed recall. Ecological validity was supported by correlations with informant reports of participants' functioning. Apartment Test Recall was not affected by education. Analysis of Receiver Operating Characteristics (ROC) showed Apartment Test Recall performed as well as word list delayed recall in distinguishing participants with and without dementia. We conclude that the Apartment Test is a valid measure of verbal memory with evidence of ecological and concurrent validity.