Epidemiology of dementia in Central Africa (EPIDEMCA): protocol for a multicentre population-based study in rural and urban areas of the Central African Republic and the Republic of Congo

Trajectory of Cognitive Decline Before and After Stroke in 14 Population Cohorts

Importance

Poststroke cognitive impairment is common, but the cognitive trajectory following a first stroke, relative to prestroke cognitive function, remains unclear.

Objective

To map the trajectory of cognitive function before any stroke and after stroke in global cognition and in 4 cognitive domains, as well as to compare the cognitive trajectory prestroke in stroke survivors with the trajectory of individuals without incident stroke over follow-up.

Design, Setting, and Participants

The study used harmonized and pooled data from 14 population-based cohort studies included in the Cohort Studies of Memory in an International Consortium collaboration. These studies were conducted from 1993 to 2019 across 11 countries among community-dwelling older adults without a history of stroke or dementia. For this study, linear mixed-effects models were used to estimate trajectories of cognitive function poststroke relative to a stroke-free cognitive trajectory. The full model adjusted for demographic and vascular risk factors. Data were analyzed from July 2022 to March 2024.

Exposure

Incident stroke.

Main outcomes and measures

The primary outcome was global cognition, defined as the standardized average of 4 cognitive domains (language, memory, processing speed, and executive function). Cognitive domain scores were formed by selecting the most commonly administered test within each domain and standardizing the scores.

Results

The study included 20 860 participants (12 261 [58.8%] female) with a mean (SD) age of 72.9 (8.0) years and follow-up of 7.51 (4.2) years. Incident stroke was associated with a substantial acute decline in global cognition (-0.25 SD; 95% CI, -0.33 to -0.17 SD), the Mini-Mental State Examination, and all cognitive domains (ranging from -0.17 SD to -0.22 SD), as well as accelerated decline in global cognition (-0.038 SD per year; 95% CI, -0.057 to -0.019 SD per year) and all domains except memory (ranging from -0.020 to -0.055 SD per year), relative to a stroke-free cognitive trajectory. There was no significant difference in prestroke slope in stroke survivors compared with the rate of decline in individuals without stroke in all cognitive measures. The mean rate of decline without a previous stroke was -0.049 SD per year (95% CI, -0.051 to -0.047 SD) in global cognition.

Conclusions and relevance

In this cohort study using pooled data from 14 cohorts, incident stroke was associated with acute and accelerated long-term cognitive decline in older stroke survivors.

Blood Pressure, Antihypertensive Use, and Late-Life Alzheimer and Non-Alzheimer Dementia Risk: An Individual Participant Data Meta-Analysis

BACKGROUND AND OBJECTIVES

Previous randomized controlled trials and longitudinal studies have indicated that ongoing antihypertensive use in late life reduces all-cause dementia risk, but the specific impact on Alzheimer dementia (AD) and non-AD risk remains unclear. This study investigates whether previous hypertension or antihypertensive use modifies AD or non-AD risk in late life and the ideal blood pressure (BP) for risk reduction in a diverse consortium of cohort studies.

METHODS

This individual participant data meta-analysis included community-based longitudinal studies of aging from a preexisting consortium. The main outcomes were risk of developing AD and non-AD. The main exposures were hypertension history/antihypertensive use and baseline systolic BP/diastolic BP. Mixed-effects Cox proportional hazards models were used to assess risk and natural splines were applied to model the relationship between BP and the dementia outcomes. The main model controlled for age, age2, sex, education, ethnoracial group, and study cohort. Supplementary analyses included a fully adjusted model, an analysis restricting to those with >5 years of follow-up and models that examined the moderating effect of age, sex, and ethnoracial group.

RESULTS

There were 31,250 participants from 14 nations in the analysis (41% male) with a mean baseline age of 72 (SD 7.5, range 60-110) years. Participants with untreated hypertension had a 36% (hazard ratio [HR] 1.36, 95% CI 1.01-1.83, p = 0.0406) and 42% (HR 1.42, 95% CI 1.08-1.87, p = 0.0135) increased risk of AD compared with "healthy controls" and those with treated hypertension, respectively. Compared with "healthy controls" both those with treated (HR 1.29, 95% CI 1.03-1.60, p = 0.0267) and untreated hypertension (HR 1.69, 95% CI 1.19-2.40, p = 0.0032) had greater non-AD risk, but there was no difference between the treated and untreated groups. Baseline diastolic BP had a significant U-shaped relationship (p = 0.0227) with non-AD risk in an analysis restricted to those with 5-year follow-up, but otherwise there was no significant relationship between baseline BP and either AD or non-AD risk.

DISCUSSION

Antihypertensive use was associated with decreased AD but not non-AD risk throughout late life. This suggests that treating hypertension throughout late life continues to be crucial in AD risk mitigation. A single measure of BP was not associated with AD risk, but DBP may have a U-shaped relationship with non-AD risk over longer periods in late life.

Predictors of white matter hyperintensities in the elderly Congolese population

Background

White matter hyperintensities (WMHs) are strongly linked to cardiovascular risk factors and other health conditions such as Alzheimer's disease. However, there is a dearth of research on this topic in low-income countries and underserved populations, especially in the Democratic Republic of Congo (DRC) where the population is aging rapidly with increasing cardiovascular risk factors and dementia-related diseases. This study evaluates health factors associated with WMH in the elderly Sub-Saharan Africa (SSA), specifically Congolese adults.

Methods

In a cross-sectional study of 77 people from the DRC, participants underwent neuroimaging to analyze WMH volume and completed clinical evaluation, laboratory-based blood exams, self-reported questionnaires, and interviews. A simple linear regression model was conducted to test the association between WMH and potential predictors (neurological status, age, sex, hypertension, diabetes, tobacco abuse, stroke, high cholesterol, cardiovascular medication, and alcohol abuse). Stepwise selection and backward elimination analyses were performed to obtain the final model. Finally, a multiple linear regression model was conducted to assess the association between WMH and variables retained in the final model (neurological status, sex, and age).

Results

Of the 77 individuals, 47 (61%) had dementia, 40 (52.6%) were males, and the mean age was 73 years (± 8.0 years standard deviation). In simple linear regression models, WMH was significantly associated with dementia (expβ1=1.75, 95% CI=1.14 - 2.71, p-value=0.01) though it had a weak association with age (expβ1=1.03, 95% CI=1.00 - 1.05, p-value=0.05) and sex (male) (expβ1=0.66, 95% CI=0.43 - 1.01, p-value=0.05). In multiple linear regression models, WMH was statistically significantly associated with dementia (expβ1=1.97, 95% CI=1.31 - 2.95, p-value =0.001), male sex (expβ2=0.54, 95% CI=0.36 - 0.80, p-value=0.003), and age (expβ3=1.03, 95% CI=1.00 - 1.06, p-value=0.03). However, WMH was not significantly associated with common cardiovascular risk factors, such as high blood pressure, diabetes, tobacco use, obesity, and high cholesterol levels.

Conclusion

WMH is significantly associated with neurological status, sex, and age in the Congolese population. Understanding these predictors may improve our ability to diagnose, assess, and develop preventative treatments for white matter disease in SSA/DRC populations, where neuroimaging is difficult to obtain.

Associations between fruit and vegetable intakes and incident depression in middle-aged and older adults from 10 diverse international longitudinal cohorts

BACKGROUND

Emerging observational evidence supports a role for higher fruit and vegetable intake in protecting against the development of depression. However, there is a scarcity of research in older adults or in low- to middle-income countries (LMICs).

METHODS

Participants were 7801 community-based adults (mean age 68.6 ± 8.0 years, 55.8 % female) without depression, from 10 diverse cohorts, including four cohorts from LMICs. Fruit and vegetable intake was self-reported via comprehensive food frequency questionnaire, short food questionnaire or diet history. Depressive symptoms were assessed using validated measures, and depression defined applying validated cut-offs. The associations between baseline fruit and vegetable intakes and incident depression over a follow-up period of three to nine years were examined using Cox regression. Analyses were performed by cohort with results meta-analysed.

RESULTS

There were 1630 cases of incident depression (21 % of participants) over 40,258 person-years of follow-up. Higher intake of fruit was associated with a lower risk of incident depression (HR 0.87, 95%CI [0.77, 0.99], I2 = 4 %). No association was found between vegetable intake and incident depression (HR 0.93, 95%CI [0.84, 1.04], I2 = 0 %).

LIMITATIONS

Diverse measures used across the different cohorts and the modest sample size of our study compared with prior studies may have prevented an association being detected for vegetable intake.

CONCLUSIONS

Our study supports a role for fruit, but not vegetable intake in protecting against depression. Research investigating different types of fruits and vegetables using standardised measures in larger cohorts of older adults from low- and middle-income countries is warranted.

Screening for dementia and associated factors in older adults from low socioeconomic communities in iLembe, KwaZulu-Natal

Background

Dementia is one of the leading non-communicable causes of disability and mortality in older adults, with recent research showing that it is increasing in low-middle-income countries compared to high-income countries. As such, multidisciplinary efforts are needed to effectively reduce the prevalence and risk of dementia through quick screening, diagnosis, and management of those with dementia and those at risk.

Aim

The study's objectives were to estimate the prevalence of dementia and measure the sociodemographic and clinical risks in older adults in low socioeconomic communities.

Setting

The study was conducted among older adults aged ≥ 60 years from the iLembe district in South Africa.

Methods

This cross-sectional, one-phased, household study was conducted to screen for dementia over 8 months between October 2018 and October 2019. Demographic and clinical data were collected using a semi-structured questionnaire. In addition, the Mini-Mental Status Exam, Ascertain Dementia Eight-item questionnaire and Instrumental Activities of Daily Living Scale were administered to a multi-stage cluster sample of 320 participants to ascertain dementia prevalence. Frequencies and multivariate logistic regression were conducted to determine risk factors correlated with dementia.

Results

The prevalence of dementia was 13.4%. Participants aged 80 years and above were 2.73 times more likely to develop dementia than participants younger than 80 years. Those with an education level of Grade 1-7 had a 69% less chance of developing dementia than those without formal education. Single participants showed an almost seven-fold increase in dementia. Lastly, depression increased the risk of dementia by two-fold.

Conclusion

Dementia was probable in over one-sixth of the sample. Dementia risk factors were both modifiable and non-modifiable.

Contribution

Dementia prevalence in South Africa is increasing and therefore it is crucial to develop a dementia plan that is specific to the South African context which will include strategies for early identification of the disease, reducing modifiable risks and strategic management of dementia associated medical conditions such as depression and vascular diseases.

Longitudinal Studies of Aging in Sub-Saharan Africa: Review, Limitations, and Recommendations in Preparation of Projected Aging Population

Background and Objectives

The United Nations has projected a 218% increase in older people in Sub-Saharan Africa (SSA) between 2019 and 2050, underscoring the need to explore changes that would occur over this time. Longitudinal studies are ideal for studying and proffering solutions to these changes. This review aims to understand the breadth and use of longitudinal studies on aging in the SSA regions, proffering recommendations in preparation for the projected aging population.

Research Design and Methods

This paper is the third of a four-part series paper of a previous systematic mapping review of aging studies in SSA. We updated the search (between 2021 and 2023) and screened the titles/abstracts and full-text articles by a pair of independent reviewers. Data were extracted using a standardized data-charting form, identifying longitudinal studies in SSA.

Results

We identified 193 studies leveraging 24 longitudinal study data sets conducted at 28 unique sites. The World Health Organization's Study on Global AGEing and Adult Health (WHO-SAGE) (n = 59, 30.5%) and Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI) (n = 51, 26.4%) were the most used longitudinal data sets. Four studies used more than one longitudinal study data set. Eighteen of the longitudinal study data sets were used only in 1-4 studies. Most (n = 150, 77.7%) of the studies used a cross-sectional analytical approach.

Discussion and Implications

Longitudinal studies on aging are sparingly being utilized in SSA. Most analyses conducted across the longitudinal data set were cross-sectional, which hindered the understanding of aging changes that occurred over time that could better inform aging policy and interventions. We call for funding bodies, such as WHO-SAGE, to develop funding competitions that focus on conducting longitudinal analyses, such as structural equation modeling, highlighting changes occurring among the aging population in SSA.

The Association of Alzheimer's Disease-Related Blood-Based Biomarkers with Cognitive Screening Test Performance in the Congolese Population in Kinshasa

BACKGROUND

Alzheimer's disease (AD), the most common cause of dementia, poses a significant global burden. Diagnosis typically involves invasive and costly methods like neuroimaging or cerebrospinal fluid (CSF) biomarker testing of phosphorylated tau (p-tau) and amyloid-β42/40 (Aβ42/40). Such procedures are especially impractical in resource-constrained regions, such as the Democratic Republic of Congo (DRC). Blood-based biomarker testing may provide a more accessible screening opportunity.

OBJECTIVE

This study aims to examine if AD-related blood-based biomarkers are associated with cognitive test performance in the Congolese population, where limited research has been conducted.

METHODS

In this cross-sectional study of 81 Congolese individuals, cognitive assessments (Alzheimer's Questionnaire (AQ) and Community Screening Interview for Dementia (CSID)) distinguished dementia cases from controls. Blood draws were taken to assess p-tau 181 and Aβ42/40 biomarkers. Relationships between the biomarkers and cognitive performance were analyzed using multiple linear regression models.

RESULTS

Lower plasma Aβ42/40 was significantly associated with lower CSID scores and higher AQ scores, indicative of AD (p < 0.001). These relationships were observed in healthy controls (CSID p = 0.01, AQ p = 0.03), but not in dementia cases. However, p-tau 181 did not exhibit significant associations with either measure. Factors such as age, sex, education, presence of APOEɛ4 allele, did not alter these relationships.

CONCLUSIONS

Understanding relationships between AD-related screening tests and blood biomarkers is a step towards utilization of blood-based biomarker tests as a screening tool for AD, especially in resource-limited regions. Further research should be conducted to evaluate blood biomarker test efficacy in larger samples and other populations.

The Association of Alzheimer's Disease-related Blood-based Biomarkers with Cognitive Screening Test Performance in the Congolese Population in Kinshasa

Background

Alzheimer's Disease (AD), the most common cause of dementia, poses a significant global burden. Diagnosis typically involves invasive and costly methods like neuroimaging or cerebrospinal fluid (CSF) biomarker testing of phosphorylated tau (p-tau) and amyloid-β42/40 (Aβ42/40). Such procedures are especially impractical in resource-constrained regions, such as the Democratic Republic of Congo (DRC). Blood-based biomarker testing may provide a more accessible screening opportunity.

Objective

This study aims to examine if AD-related blood-based biomarkers are associated with cognitive test performance in the Congolese population, where limited research has been conducted.

Methods

In this cross-sectional study of 81 Congolese individuals, cognitive assessments (Alzheimer's Questionnaire (AQ) and Community Screening Interview for Dementia (CSID)) distinguished dementia cases from controls. Blood draws were taken to assess p-tau 181 and Aβ42/40 biomarkers. Relationships between the biomarkers and cognitive performance were analyzed using multiple linear regression models.

Results

Lower plasma Aβ42/40 was significantly associated with lower CSID scores and higher AQ scores, indicative of AD (p<0.001). These relationships were observed in healthy controls (CSID p=0.01, AQ p=0.03), but not in dementia cases. However, p-tau 181 did not exhibit significant associations with either measure. Factors such as age, sex, education, presence of APOE e4 allele, did not alter these relationships.

Conclusion

Understanding relationships between AD-related screening tests and blood-biomarkers is a step towards utilization of blood-based biomarker tests as a screening tool for AD, especially in resource-limited regions. Further research should be conducted to evaluate blood biomarker test efficacy in larger samples and other populations.

Use of Antihypertensives, Blood Pressure, and Estimated Risk of Dementia in Late Life: An Individual Participant Data Meta-Analysis

Importance

The utility of antihypertensives and ideal blood pressure (BP) for dementia prevention in late life remains unclear and highly contested.

Objectives

To assess the associations of hypertension history, antihypertensive use, and baseline measured BP in late life (age >60 years) with dementia and the moderating factors of age, sex, and racial group.

Data Source and Study Selection

Longitudinal, population-based studies of aging participating in the Cohort Studies of Memory in an International Consortium (COSMIC) group were included. Participants were individuals without dementia at baseline aged 60 to 110 years and were based in 15 different countries (US, Brazil, Australia, China, Korea, Singapore, Central African Republic, Republic of Congo, Nigeria, Germany, Spain, Italy, France, Sweden, and Greece).

Data Extraction and Synthesis

Participants were grouped in 3 categories based on previous diagnosis of hypertension and baseline antihypertensive use: healthy controls, treated hypertension, and untreated hypertension. Baseline systolic BP (SBP) and diastolic BP (DBP) were treated as continuous variables. Reporting followed the Preferred Reporting Items for Systematic Review and Meta-Analyses of Individual Participant Data reporting guidelines.

Main Outcomes and Measures

The key outcome was all-cause dementia. Mixed-effects Cox proportional hazards models were used to assess the associations between the exposures and the key outcome variable. The association between dementia and baseline BP was modeled using nonlinear natural splines. The main analysis was a partially adjusted Cox proportional hazards model controlling for age, age squared, sex, education, racial group, and a random effect for study. Sensitivity analyses included a fully adjusted analysis, a restricted analysis of those individuals with more than 5 years of follow-up data, and models examining the moderating factors of age, sex, and racial group.

Results

The analysis included 17 studies with 34 519 community dwelling older adults (20 160 [58.4%] female) with a mean (SD) age of 72.5 (7.5) years and a mean (SD) follow-up of 4.3 (4.3) years. In the main, partially adjusted analysis including 14 studies, individuals with untreated hypertension had a 42% increased risk of dementia compared with healthy controls (hazard ratio [HR], 1.42; 95% CI 1.15-1.76; P = .001) and 26% increased risk compared with individuals with treated hypertension (HR, 1.26; 95% CI, 1.03-1.53; P = .02). Individuals with treated hypertension had no significant increased dementia risk compared with healthy controls (HR, 1.13; 95% CI, 0.99-1.28; P = .07). The association of antihypertensive use or hypertension status with dementia did not vary with baseline BP. There was no significant association of baseline SBP or DBP with dementia risk in any of the analyses. There were no significant interactions with age, sex, or racial group for any of the analyses.

Conclusions and Relevance

This individual patient data meta-analysis of longitudinal cohort studies found that antihypertensive use was associated with decreased dementia risk compared with individuals with untreated hypertension through all ages in late life. Individuals with treated hypertension had no increased risk of dementia compared with healthy controls.

CERAD (Consortium to Establish a Registry for Alzheimer's Disease) Neuropsychology Assessment Battery: 35 Years and Counting

BACKGROUND

In 1986, the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) was mandated to develop a brief neuropsychological assessment battery (CERAD-NAB) for AD, for uniform neuropsychological assessment, and information aggregation. Initially used across the National Institutes of Aging-funded Alzheimer's Disease Research Centers, it has become widely adopted wherever information is desired on cognitive status and change therein, particularly in older populations.

OBJECTIVE

Our purpose is to provide information on the multiple uses of the CERAD-NAB since its inception, and possible further developments.

METHODS

Since searching on "CERAD neuropsychological assessment battery" or similar terms missed important information, "CERAD" alone was entered into PubMed and SCOPUS, and CERAD-NAB use identified from the resulting studies. Use was sorted into major categories, e.g., psychometric information, norms, dementia/differential dementia diagnosis, epidemiology, intervention evaluation, genetics, etc., also translations, country of use, and alternative data gathering approaches.

RESULTS

CERAD-NAB is available in ∼20 languages. In addition to its initial purpose assessing AD severity, CERAD-NAB can identify mild cognitive impairment, facilitate differential dementia diagnosis, determine cognitive effects of naturally occurring and experimental interventions (e.g., air pollution, selenium in soil, exercise), has helped to clarify cognition/brain physiology-neuroanatomy, and assess cognitive status in dementia-risk conditions. Surveys of primary and tertiary care patients, and of population-based samples in multiple countries have provided information on prevalent and incident dementia, and cross-sectional and longitudinal norms for ages 35-100 years.

CONCLUSION

CERAD-NAB has fulfilled its original mandate, while its uses have expanded, keeping up with advances in the area of dementia.

The relationship between alcohol use and dementia in adults aged more than 60 years: a combined analysis of prospective, individual-participant data from 15 international studies

AIM

To synthesize international findings on the alcohol-dementia relationship, including representation from low- and middle-income countries.

METHODS

Individual participant data meta-analysis of 15 prospective epidemiological cohort studies from countries situated in six continents. Cox regression investigated the dementia risk associated with alcohol use in older adults aged over 60 years. Additional analyses assessed the alcohol-dementia relationship in the sample stratified by sex and by continent. Participants included 24 478 community dwelling individuals without a history of dementia at baseline and at least one follow-up dementia assessment. The main outcome measure was all-cause dementia as determined by clinical interview.

RESULTS

At baseline, the mean age across studies was 71.8 (standard deviation = 7.5, range = 60-102 years), 14 260 (58.3%) were female and 13 269 (54.2%) were current drinkers. During 151 636 person-years of follow-up, there were 2124 incident cases of dementia (14.0 per 1000 person-years). When compared with abstainers, the risk for dementia was lower in occasional [hazard ratio (HR) = 0.78; 95% confidence interval (CI) = 0.68-0.89], light-moderate (HR = 0.78; 95% CI = 0.70-0.87) and moderate-heavy drinkers (HR = 0.62; 95% CI = 0.51-0.77). There was no evidence of differences between life-time abstainers and former drinkers in terms of dementia risk (HR = 0.98; 95% CI = 0.81-1.18). In dose-response analyses, moderate drinking up to 40 g/day was associated with a lower risk of dementia when compared with lif-time abstaining. Among current drinkers, there was no consistent evidence for differences in terms of dementia risk. Results were similar when the sample was stratified by sex. When analysed at the continent level, there was considerable heterogeneity in the alcohol-dementia relationship.

CONCLUSIONS

Abstinence from alcohol appears to be associated with an increased risk for all-cause dementia. Among current drinkers, there appears to be no consistent evidence to suggest that the amount of alcohol consumed in later life is associated with dementia risk.

Factors associated with verbal fluency in older adults living with HIV in West Africa: A longitudinal study

OBJECTIVE

Verbal fluency decline, observed both in aging and HIV infection, has been related to lower quality of life. This study aimed to evaluate the factors associated with categorical fluency in people living with HIV (PLHIV) aged ≥60 years living in West Africa.

METHODS

In this longitudinal study, PLHIV aged ≥60 years, on antiretroviral therapy (ART) for ≥6 months were included in three clinics (two in Côte d'Ivoire, one in Senegal) participating in the West Africa International epidemiological Databases to Evaluate AIDS (IeDEA) collaboration. Categorical fluency was evaluated with the Isaacs Set Test at 60 s at baseline and 2 years later. Factors associated with verbal fluency baseline performance and annual rates of changes were evaluated using multivariate linear regression models.

RESULTS

Ninety-seven PLHIV were included with 41 of them (42%) having a 2-year follow-up visit. The median age was 64 (62-67), 45.4% were female, and 89.7% had an undetectable viral load. The median annual change in categorical fluency scores was -0.9 (IQR: -2.7 to 1.8). Low baseline categorical fluency performance and its decline were associated with older age and being a female. Low educational level was associated with low baseline categorical fluency performance but not with its decline. Categorical fluency decline was also associated with marital status and hypertension.

CONCLUSIONS

Among older West African PLHIV, usual socio-demographic variables and hypertension were the main factors associated with low categorical fluency performance and/or its decline. Interventions that focus on supporting cardiometabolic health are highly recommended to prevent cognitive disorders in PLHIV.

Associations between social connections and cognition: a global collaborative individual participant data meta-analysis

BACKGROUND

Poor social connections (eg, small networks, infrequent interactions, and loneliness) are modifiable risk factors for cognitive decline. Existing meta-analyses are limited by reporting aggregate responses, a focus on global cognition, and combining social measures into single constructs. We aimed to investigate the association between social connection markers and the rate of annual change in cognition (ie, global and domain-specific), as well as sex differences, using an individual participant data meta-analysis.

METHODS

We harmonised data from 13 longitudinal cohort studies of ageing in North America, South America, Europe, Africa, Asia, and Australia. Studies were eligible for inclusion if they had baseline data for social connection markers and at least two waves of cognitive scores. Follow-up periods ranged from 0 years to 15 years across cohorts. We included participants with cognitive data for at least two waves and social connection data for at least one wave. We then identified and excluded people with dementia at baseline. Primary outcomes were annual rates of change in global cognition and cognitive domain scores over time until final follow-up within each cohort study analysed by use of an individual participant data meta-analysis. Linear mixed models within cohorts used baseline social connection markers as predictors of the primary outcomes. Effects were pooled in two stages using random-effects meta-analyses. We assessed the primary outcomes in the main (partially adjusted) and fully adjusted models. Partially adjusted models controlled for age, sex, and education; fully adjusted models additionally controlled for diabetes, hypertension, smoking, cardiovascular risk, and depression.

FINDINGS

Of the 40 006 participants in the 13 cohort studies, we excluded 1392 people with dementia at baseline. 38 614 individual participants were included in our analyses. For the main models, being in a relationship or married predicted slower global cognitive decline (b=0·010, 95% CI 0·000-0·019) than did being single or never married; living with others predicted slower global cognitive (b=0·007, 0·002-0·012), memory (b=0·017, 0·006-0·028), and language (b=0·008, 0·000-0·015) decline than did living alone; and weekly interactions with family and friends (b=0·016, 0·006-0·026) and weekly community group engagement (b=0·030, 0·007-0·052) predicted slower memory decline than did no interactions and no engagement. Never feeling lonely predicted slower global cognitive (b=0·047, 95% CI 0·018-0·075) and executive function (b=0·047, 0·017-0·077) decline than did often feeling lonely. Degree of social support, having a confidante, and relationship satisfaction did not predict cognitive decline across global cognition or cognitive domains. Heterogeneity was low (I2=0·00-15·11%) for all but two of the significant findings (association between slower memory decline and living with others [I2=58·33%] and community group engagement, I2=37·54-72·19%), suggesting robust results across studies.

INTERPRETATION

Good social connections (ie, living with others, weekly community group engagement, interacting weekly with family and friends, and never feeling lonely) are associated with slower cognitive decline.

FUNDING

EU Joint Programme-Neurodegenerative Disease Research grant, funded by the National Health and Medical Research Council Australia, and the US National Institute on Aging of the US National Institutes of Health.

Dementia in Africa: Current evidence, knowledge gaps, and future directions

In tandem with the ever-increasing aging population in low and middle-income countries, the burden of dementia is rising on the African continent. Dementia prevalence varies from 2.3% to 20.0% and incidence rates are 13.3 per 1000 person-years with increasing mortality in parts of rapidly transforming Africa. Differences in nutrition, cardiovascular factors, comorbidities, infections, mortality, and detection likely contribute to lower incidence. Alzheimer's disease, vascular dementia, and human immunodeficiency virus/acquired immunodeficiency syndrome-associated neurocognitive disorders are the most common dementia subtypes. Comprehensive longitudinal studies with robust methodology and regional coverage would provide more reliable information. The apolipoprotein E (APOE) ε4 allele is most studied but has shown differential effects within African ancestry compared to Caucasian. More candidate gene and genome-wide association studies are needed to relate to dementia phenotypes. Validated culture-sensitive cognitive tools not influenced by education and language differences are critically needed for implementation across multidisciplinary groupings such as the proposed African Dementia Consortium.

Self-Reported Vision Impairment and Frailty among Older People with Low Cognitive Performance in Central Africa: EPIDEMCA Population-Based Study

INTRODUCTION

Very little is known about the impact of vision impairment (VI) on physical health in late-life in sub-Saharan Africa populations, whereas many older people experience it. We investigated the association between self-reported VI and frailty in Central African older people with low cognitive performance.

METHODS

It was cross-sectional analysis of data from the Epidemiology of Dementia in Central Africa (EPIDEMCA) population-based study. After screening for cognitive impairment, older people with low cognitive performance were selected. Frailty was assessed using the Study of Osteoporotic Fracture index. Participants who met one of the 3 parameters assessed (unintentional weight loss, inability to do 5 chair stands, and low energy level) were considered as pre-frail, and those who met 2 or more parameters were considered as frail. VI was self-reported. Associations were investigated using multinomial logistic regression models.

RESULTS

Out of 2,002 older people enrolled in EPIDEMCA, 775 (38.7%) had low cognitive performance on the screening test. Of them, 514 participants (sex ratio: 0.25) had available data on VI and frailty and were included in the analyses. In total, 360 (70%) self-reported VI. Prevalence of frailty was estimated at 64.9% [95% confidence interval: 60.9%-69.1%] and 23.7% [95% CI: 20.1%-27.4%] for pre-frailty. After full adjustment, self-reported VI was associated with frailty (adjusted odds ratio = 2.2; 95% CI: 1.1-4.3) but not with pre-frailty (adjusted odds ratio = 1.8; 95% CI: 0.9-3.7).

CONCLUSION

In Central African older people with low cognitive performance, those who self-reported VI were more likely to experience frailty. Our findings suggest that greater attention should be devoted to VI among this vulnerable population in order to identify early frailty onset and provide adequate care management.

Characterizing Demographic, Racial, and Geographic Diversity in Dementia Research: A Systematic Review

Importance

For informed decision making on diagnosis and treatment of dementia, physicians and their patients rely on the generalizability of evidence from published studies to clinical practice. However, it is uncertain whether everyday care of elderly patients with dementia is sufficiently captured in contemporary research.

Objective

To systematically review contemporary dementia research in terms of study and patient characteristics in order to assess generalizability of research findings.

Evidence Review

PubMed was searched for dementia studies published in the top 100 journals in the fields of neurology and neuroscience, geriatrics, psychiatry, and general medicine between September 1, 2018, and August 31, 2019. Two reviewers extracted study characteristics, including setting, number of participants, age at diagnosis, and use of biomarkers.

Findings

Among 513 identified studies, 211 (41%) included fewer than 50 individuals with dementia and were excluded. The remaining 302 studies included a median (interquartile range) of 214 patients (98-628) with a mean (SD) age at diagnosis of 74.1 years (8.0). Age at diagnosis differed with study setting. Patients in the 180 clinic-based studies had a mean (SD) age of 71.8 (6.4) years at time of diagnosis compared with 80.6 (4.7) years among patients in the 79 population-based studies (mean difference, 8.8 years; 95% CI, 7.3-10.2). Use of magnetic resonance imaging, positron emission tomography imaging, and cerebrospinal fluid imaging was mostly done in clinic-based studies (80% to 96%) and consequently in relatively young patients (mean [SD] age, 71.6 [5.1] years). A longitudinal design was more common in population-based studies than in clinic-based studies (82 % vs 40%). Most studies originated from North America and Europe (89%), including almost exclusively White participants (among 74 studies [22%] reporting on ethnicity: median [interquartile range], 89% [78-97]). The 3 most studied cohorts represented 21% of all included study populations.

Conclusions and Relevance

Contemporary dementia research is limited in terms of racial and geographic diversity and draws largely from clinic-based populations with relatively young patients. Greater inclusivity and deeper phenotyping in unselected cohorts could improve generalizability as well as diagnosis and development of effective treatments for all patients with dementia.

Effects of Age, Level of Education and HIV Status on Cognitive Performance in West African Older Adults: The West Africa IeDEA Cohort Collaboration

An in-depth understanding of the impact of aging, cognitive reserve, and HIV status on cognitive function is needed in older West African adults. Ninety-nine HIV-negative and 334 HIV-positive adults aged ≥ 50 years were enrolled in three clinics (Senegal and Côte d'Ivoire) participating in the IeDEA West Africa collaboration. All subjects underwent the Free and Cued Selective Reminding Test (FCSRT) and the Isaacs Set Test (IST). Age (both linear and quadratic), education level, and HIV status effects on Z-scores were assessed using multivariate linear regression models. Interactions between HIV status and age or educational level were tested. In the present cohort of older West African adults, the role of age and educational level on episodic memory and verbal fluency was observed without revealing an interaction between HIV status and age effect. As age had quadratic effects, older HIV-positive adults should not be considered as a unique group irrespective of their age. Low-educated HIV-positive patients had the lowest verbal fluency performance compared to others. Further studies are needed to duplicate these results. In clinical settings, screening and adapted programs focusing on improving cognition in those patients are needed.

Cardiovascular Health and Near Visual Impairment Among Older Adults in the Republic of Congo: A Population-Based Study

BACKGROUND

Visual impairment (VI) and determinants of poor cardiovascular health are very common in Sub-Saharan Africa. However, we do not know whether these determinants are associated with VI among older adults in this region. This study aimed at investigating the association between the determinants of poor cardiovascular health and near VI among older adults living in Congo.

METHODS

Participants were Congolese adults aged 65 or older included in Epidemiology of Dementia in Central Africa-Follow-up population-based cohort. Near VI was defined as visual acuity less than 20/40 measured at 30 cm. Associations between determinants of poor cardiovascular health collected at baseline and near visual acuity measured at first follow-up were investigated using multivariable logistic regression models.

RESULTS

Among the 549 participants included, 378 (68.8%; 95% confidence interval [CI]: 64.9%-72.7%]) had near VI. Of the determinants of poor cardiovascular health explored, we found that having high body mass index of at least 25 kg/m2 (odds ratio [OR] = 2.15; 95% CI: 1.25-3.68), diabetes (OR = 2.12; 95% CI: 1.06-4.25) and hypertension (OR = 1.65; 95% CI: 1.02-2.64) were independently associated with near VI.

CONCLUSIONS

Several determinants of poor cardiovascular health were associated with near VI in this population. This study suggests that promoting good cardiovascular health could represent a target for VI prevention among older adults.

Prevalence of Dementia among Well-Educated Old-Age Pensioners in Parakou (Benin) in 2014

INTRODUCTION

The number of people living with dementia is growing worldwide and most rapidly in low- and middle-income countries. Little is known about dementia in Benin. We estimated the prevalence of dementia among retired people in Parakou, a northern city in Benin, and then assessed associated factors.

METHODS

A cross-sectional study was performed in Parakou from July to August 2014. Participants were recruited at 2 centers, the National Center of Social Security and the Public Treasury of Benin. Participants with cognitive impairment were defined as having a low cognitive score (<7) for the brief version of the Community Screening Interview for Dementia and were invited to neurological examination. DSM-IV-TR criteria were used to diagnose dementia and the HACHINSKI score was used to differentiate dementia subtypes. A logistic regression model was performed to identify factors associated with dementia.

RESULTS

Overall, 440 retired people were included in the study. They were mainly male (92.3%) and their mean age was 64.9 ± 6.0 years. The prevalence of cognitive impairment was 7.7% (95% CI 5.2-10.2). Fourteen participants were diagnosed with dementia, representing a prevalence of 3.2% (95% CI 1.5-4.8). Alzheimer disease was the most frequent subtype (64.3%), followed by vascular dementia (21.4%). Retired people diagnosed with dementia were all men and were aged between 61 and 71 years. Most of them were living alone. The main factors associated with dementia were older age, low fruit and vegetables consumption, and living alone.

DISCUSSION

This study showed a low prevalence of dementia among retired older people in Benin. Despite this, greater attention must be given to the potential burden dementia places on families for better care, before the expected aging of the population becomes more significant.

Arm Based on LEg blood pressures (ABLE-BP): can systolic leg blood pressure measurements predict systolic brachial blood pressure? Protocol for an individual participant data meta-analysis from the INTERPRESS-IPD Collaboration

INTRODUCTION

Blood pressure (BP) is normally measured on the upper arm, and guidelines for the diagnosis and treatment of high BP are based on such measurements. Leg BP measurement can be an alternative when brachial BP measurement is impractical, due to injury or disability. Limited data exist to guide interpretation of leg BP values for hypertension management; study-level systematic review findings suggest that systolic BP (SBP) is 17 mm Hg higher in the leg than the arm. However, uncertainty remains about the applicability of this figure in clinical practice due to substantial heterogeneity.

AIMS

To examine the relationship between arm and leg SBP, develop and validate a multivariable model predicting arm SBP from leg SBP and investigate the prognostic association between leg SBP and cardiovascular disease and mortality.

METHODS AND ANALYSIS

Individual participant data (IPD) meta-analyses using arm and leg SBP measurements for 33 710 individuals from 14 studies within the Inter-arm blood pressure difference IPD (INTERPRESS-IPD) Collaboration. We will explore cross-sectional relationships between arm and leg SBP using hierarchical linear regression with participants nested by study, in multivariable models. Prognostic models will be derived for all-cause and cardiovascular mortality and cardiovascular events.

ETHICS AND DISSEMINATION

Data originate from studies with prior ethical approval and consent, and data sharing agreements are in place-no further approvals are required to undertake the secondary analyses proposed in this protocol. Findings will be published in peer-reviewed journal articles and presented at conferences. A comprehensive dissemination strategy is in place, integrated with patient and public involvement.

PROSPERO REGISTRATION NUMBER

CRD42015031227.

Apolipoprotein E ϵ4 allele and neuropsychiatric symptoms among older adults in Central Africa (EPIDEMCA study)

OBJECTIVES

To evaluate the association between neuropsychiatric symptoms and apolipoprotein E (APOE) ϵ4 allele among older people in Central African Republic (CAR) and the Republic of Congo (ROC).

DESIGN

Multicenter population-based study following a two-phase design.

SETTING

From 2011 to 2012, rural and urban areas of CAR and ROC.

PARTICIPANTS

People aged 65 and over.

MEASUREMENTS

Following screening using the Community Screening Interview for Dementia, participants with low cognitive scores (CSI-D ≤ 24.5) underwent clinical assessment. Dementia diagnosis followed the DSM-IV criteria and Peterson's criteria were considered for Mild Cognitive Impairment (MCI). Neuropsychiatric symptoms were evaluated through the brief version of the Neuropsychiatric Inventory (NPI-Q). Blood samples were taken from all consenting participants before APOE genotyping was performed by polymerase chain reaction (PCR). Logistic regression models were used to evaluate the association between the APOE ϵ4 allele and neuropsychiatric symptoms.

RESULTS

Overall, 322 participants had complete information on both neuropsychiatric symptoms and APOE status. Median age was 75.0 years and 81.1% were female. Neuropsychiatric symptoms were reported by 192 participants (59.8%) and at least 1 APOE ϵ4 allele was present in 135 (41.9%). APOE ϵ4 allele was not significantly associated with neuropsychiatric symptoms but showed a trend toward a protective effect in some models.

CONCLUSION

This study is the first one investigating the association between APOE ϵ4 and neuropsychiatric symptoms among older people in sub-Saharan Africa (SSA). Preliminary findings indicate that the APOE ϵ4 allele was not associated with neuropsychiatric symptoms. Further research seems, however, needed to investigate the protective trend found in this study.

Associations Between Systolic Interarm Differences in Blood Pressure and Cardiovascular Disease Outcomes and Mortality: Individual Participant Data Meta-Analysis, Development and Validation of a Prognostic Algorithm: The INTERPRESS-IPD Collaboration

Systolic interarm differences in blood pressure have been associated with all-cause mortality and cardiovascular disease. We undertook individual participant data meta-analyses to (1) quantify independent associations of systolic interarm difference with mortality and cardiovascular events; (2) develop and validate prognostic models incorporating interarm difference, and (3) determine whether interarm difference remains associated with risk after adjustment for common cardiovascular risk scores. We searched for studies recording bilateral blood pressure and outcomes, established agreements with collaborating authors, and created a single international dataset: the Inter-arm Blood Pressure Difference - Individual Participant Data (INTERPRESS-IPD) Collaboration. Data were merged from 24 studies (53 827 participants). Systolic interarm difference was associated with all-cause and cardiovascular mortality: continuous hazard ratios 1.05 (95% CI, 1.02-1.08) and 1.06 (95% CI, 1.02-1.11), respectively, per 5 mm Hg systolic interarm difference. Hazard ratios for all-cause mortality increased with interarm difference magnitude from a ≥5 mm Hg threshold (hazard ratio, 1.07 [95% CI, 1.01-1.14]). Systolic interarm differences per 5 mm Hg were associated with cardiovascular events in people without preexisting disease, after adjustment for Atherosclerotic Cardiovascular Disease (hazard ratio, 1.04 [95% CI, 1.00-1.08]), Framingham (hazard ratio, 1.04 [95% CI, 1.01-1.08]), or QRISK cardiovascular disease risk algorithm version 2 (QRISK2) (hazard ratio, 1.12 [95% CI, 1.06-1.18]) cardiovascular risk scores. Our findings confirm that systolic interarm difference is associated with increased all-cause mortality, cardiovascular mortality, and cardiovascular events. Blood pressure should be measured in both arms during cardiovascular assessment. A systolic interarm difference of 10 mm Hg is proposed as the upper limit of normal. Registration: URL: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42015031227.

Predictive formulas for estimation of height in sub-Saharan African older people: A new formula (EPIDEMCA study)

OBJECTIVES

Chumlea's formulas are a way of predicting height from knee height (KHt), including among individuals >60 y of age who cannot stand upright. However, the formulas were developed with white and African American people and have not yet been validated in native Africans >60 y of age. The aims of the study were to assess Chumlea's formulas in older people in central Africa and to propose a new validated formula for the same population.

METHODS

Height (MHt) and KHt were measured in a population of individuals >65 y of age from the Republic of Congo and the central African Republic. Predicted height (PHt) was calculated using Chumlea's formulas for the American black population (CBP) and for whites (CC). The percentages of accurate predictions (±5 cm) were compared between MHt and PHt. A new formula was estimated after randomization in a derivation sample (n = 877) and assessed for accuracy in a validation sample (n = 877).

RESULTS

The study included 1754 individuals. Prediction was accurate (±5 cm) in 66.8% and 63.2% of CBP and CC, respectively. Overestimation was as high as 24.1% and 29%, respectively. Because an overestimation is unacceptable in clinical practice and population surveys, a new formula was proposed: height (cm) = 72.75 + (1.86 × KHt [cm]) - (0.13 × age [y]) + 3.41 × sex (0: women; 1: men). This new formula significantly increases accuracy (71.3%) and decreases overestimation (14.7%). The nutritional status based on body mass index did not differ with the MHt and the PHt by the new formula.

CONCLUSION

Chumlea's formulas provided a poor estimate of height in this population sample. The proposed formula more accurately estimates height in older native Africans. This formula should be tested in other sub-Saharan African countries to extend its use in clinical practice and in future studies.

Development of the Central Africa Daily Functioning Interference Scale for Dementia Diagnosis in Older Adults: The EPIDEMCA Study

BACKGROUND

There are a few validated tools capable of assessing the dimensions essential for the diagnosis of dementia and cognitive disorders in sub-Saharan Africa.

OBJECTIVES

Our aim was to develop an adapted tool, the Central African - Daily Functioning Interference (DFI) scale.

METHODS

An initial 16-item scale of activity limitations and participation restrictions was completed by 301 participants with low cognitive performances to assess their level of DFI. A psychometric evaluation was performed using Item Response Theory.

RESULTS

A unidimensional 10-item scale emerged with a reasonable coverage of DFI (thresholds range: -1.067 to 1.587) with good item discrimination properties (1.397-4.076) and a high reliability (Cronbach's al pha = 0.92). The cutoff for detecting 96% of those with dementia was with a latent score ≥0.035 that corresponds to the LAUNDRY limitation.

CONCLUSIONS

These results provide valuable support for the reliability and internal validity of an operational 10-item scale for DFI assessment used in Central Africa for the diagnosis of dementia in the elderly.

Severity of Neuropsychiatric Symptoms and Distress in Dementia among Older People in Central Africa (EPIDEMCA Study)

OBJECTIVES

Neuropsychiatric symptoms are common in dementia. Limited data are available concerning their association with dementia in developing countries. Our aim was to describe the severity of neuropsychiatric symptoms among older people, evaluate the distress experienced by caregivers, and assess which neuropsychiatric symptoms were specifically associated with dementia among older adults in Central Africa.

DESIGN

This study is part of the EPIDEMCA program, a cross-sectional multicenter population-based study.

SETTING

The EPIDEMCA program was conducted from November 2011 to December 2012 in urban and rural areas of the Central African Republic and the Republic of the Congo.

PARTICIPANTS

Participants were older people (≥65 y) included in the EPIDEMCA program who underwent a neuropsychiatric evaluation. The sample included overall 532 participants, of whom 130 participants had dementia.

MEASUREMENTS

Neuropsychiatric symptoms were assessed with the brief version of the Neuropsychiatric Inventory including the evaluation of severity and associated distress. Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision, criteria were followed to diagnose dementia. A logistic regression model was used to identify associated neuropsychiatric symptoms.

RESULTS

The prevalence of neuropsychiatric symptoms was 89.9% (95% confidence interval = 84.6-95.1) among people living with dementia. The overall median severity score for neuropsychiatric symptoms was 9 [interquartile range [IQR] = 6-12], and the overall median distress score was 7 [IQR = 4-10]. Overall median scores of both severity and distress were significantly increased with the number of neuropsychiatric symptoms, the presence of dementia, and dementia severity. Depression, delusions, apathy, disinhibition, and aberrant motor behavior were associated with dementia after multivariate analysis.

CONCLUSION

This report is one of the few population-based studies on neuropsychiatric symptoms among older people with dementia in Sub-Saharan Africa and the first one evaluating the severity of those symptoms and distress experienced by caregivers. Individual neuropsychiatric symptoms were strongly associated with dementia in older people and require great attention considering their burden on populations. J Am Geriatr Soc 68:180-185, 2019.

Body mass index and peripheral arterial disease, a "U-shaped" relationship in elderly African population - the EPIDEMCA study

Background: There is no study available concerning specifically the role of underweight in PAD prevalence. Patients and methods: Individuals ≥ 65 years living in urban and rural areas of two countries in Central Africa (Central African Republic and the Republic of Congo) were invited. Demographic, clinical and biological data were collected, and ankle-brachial index measured. BMI was calculated as weight/height² and participants were categorized according to the World Health Organization as with underweight (< 18.5 kg/m²), normal weight (18.5-24.9 kg/m²), overweight (25-29.9 kg/m²), and obese (≥ 30 kg/m²). Results: Among the 1815 participants (age 73.0 years, 61.8 % females), the prevalence of underweight was 34.1 %, higher in subjects with PAD than in PAD free subjects (37.1 % vs. 33.5 %, p = 0.0333). The overall prevalence of PAD was 14.3 %. Underweight and obesity were still significantly associated with PAD after adjustment to all potential confounding factors (OR: 2.09, p = 0.0009 respectively OR: 1.90, p = 0.0336) while overweight was no more significantly associated with PAD after multivariate analysis. Conclusions: While obesity is a well-known PAD associated marker, low BMI provides novel independent and incremental information on African subject's susceptibility to present PAD, suggesting a "U-shaped" relationship between BMI and PAD in this population.

Ankle Brachial Index (ABI) predicts 2-year mortality risk among older adults in the Republic of Congo: The EPIDEMCA-FU study

BACKGROUND AND AIMS

Peripheral artery disease (PAD) is known to be associated with mortality in high income countries but no data regarding Sub-Saharan Africa (SSA) populations are documented. This study aimed at assessing the prognostic value of the Ankle Brachial Index (ABI) among older adults in the Republic of Congo.

METHODS

Congolese subjects ≥65 years were included in a longitudinal population-based survey (EPIDEMCA-FU). Demographic, biological, and clinical data were collected at baseline. PAD was defined by an ABI≤0.90. Information on mortality was collected from key informants in participants' households. Cox proportional hazard models, adjusted for traditional and cardiovascular risk factors, were fitted to evaluate the association between an ABI≤0.90 and death.

RESULTS

1029 participants were recruited at baseline. ABI measurement was obtained from 927 participants, of whom 17.4% presented an ABI≤0.90. During a 2-year follow-up, a total of 83 (9.1%) deaths were recorded. Mortality was higher in the low-ABI group with 23 deaths (14.7%) vs. 57 (7.8%) and 3 (12.0%), respectively among those with 0.90 < ABI<1.4 and ABI≥1.40 (p = 0.039). After adjustment, an ABI≤0.90 was associated with an increased risk of mortality (HR = 1.86; 95%CI 1.04-3.87). Mortality was also independently associated with increasing age (HR = 1.05; 95%CI 1.02-1.09), dementia (HR = 2.73; 95% CI 1.15-8.05), alcohol use (HR = 0.51; 95%CI 0.29-0.88) and female sex (HR = 0.37; 95%CI 0.19-0.72).

CONCLUSIONS

In this study, a low ABI predicted an increased mortality risk among older people. ABI may represent a simple and inexpensive tool to identify older people at high risk of death in SSA.

Impact of urbanization on cognitive disorders

PURPOSE OF REVIEW

Cognitive disorders remain a major global burden with an estimated 47 million people living with dementia worldwide. Rates of cognitive disorders are expected to grow, especially as the global population ages. Global trends also indicate that about half of the global population lives in urban settings. To help guide future research, as well as the development of targeted and tailored interventions to prevent and care for people living with cognitive disorders, we present an up-to-date review and summary of the literature examining cognitive disorders and urbanization.

RECENT FINDINGS

We reviewed the literature between January 2017 and September 2018 on cognitive disorders and urbanization. We found that rates of dementia among urban dwellers tends to be lower than those of rural dwellers. Leading theories explaining this difference tend to focus on better access to higher quality education, as well as public and health services among urban dwellers. We also found that greater exposure to air and noise pollutants may negatively impact cognition.

SUMMARY

The reasons why older adults living in urban settings appear to have lower rates of dementia and better performance on cognitive measures are not well understood. Furthermore, the definitions of urban and rural and cognitive disorder, as well as how they are measured vary greatly between studies, making comparisons difficult.

Neuropsychiatric symptoms among older adults living in two countries in Central Africa (EPIDEMCA study)

OBJECTIVES

Our study aimed at estimating the prevalence of neuropsychiatric symptoms and investigating associated factors among older adults living in two countries in Central Africa (Central African Republic [CAR] and Republic of Congo [ROC]).

METHODS

The EPIDEMCA multicentre population-based study was carried out in rural and urban areas of CAR and ROC between 2011 and 2012 among people aged 65 and over. After cognitive screening using the Community Screening Interview for Dementia, participants with low performances underwent neurological examination including the brief version of the Neuropsychiatric Inventory Questionnaire (NPI-Q). Multivariate logistic regression analyses were performed to identify factors independently associated with neuropsychiatric symptoms in this population.

RESULTS

NPI-Q data were available for 532 participants. Overall, 333 elderly people (63.7%) reported at least one neuropsychiatric symptom. The prevalence of neuropsychiatric symptoms was 89.9% (95% CI, 84.6-95.1) in participants with dementia, 73.4% (95% CI, 65.1-81.7) in participants with mild cognitive impairment (MCI), and 48.7% (95% CI, 42.9-54.6) in participants with no MCI nor dementia after neurological examination (P < 0.0001). The most common symptoms were depression, anxiety, and irritability. Participants living in Gamboma, with normal hearing and with friends in the community, were less likely to present neuropsychiatric symptoms. Physical disability, difficulties in eating, female sex, and dementia were significantly associated with neuropsychiatric symptoms.

CONCLUSION

Neuropsychiatric symptoms are common among older people with neurocognitive disorders in CAR and ROC. Our results confirm those from previous studies in Nigeria and Tanzania. Nevertheless, knowledge of these symptoms remains limited in sub-Saharan Africa, hampering their appropriate management.

A review of the 10/66 dementia research group

BACKGROUND

In this review we discuss how the study of dementia epidemiology in Low- and Middle-Income Countries (LMICs) has changed in the last 20 years, and specifically to review the evidence created by the 10/66 Dementia Research Group (DRG) and discuss future directions for research.

METHODS

We identified and collated all the papers related to the 10/66 Dementia Research Group, including papers from groups who adopted the 10/66 methodology, that have been published in peer-reviewed journals.

RESULTS

Over 200 papers including data from Africa, Asia, Europe and Latin America and the Caribbean were identified by this review. Many of the findings revolved around the epidemiology of dementia, mental health and non-communicable diseases, including the cross-cultural development and validation of measurement tools of cognition and functioning, need for care, care arrangements and mental health. Social ageing, care dependence and caregiver interventions were also topics that the group had published on.

DISCUSSION

A body of evidence has been generated that has challenged the view, prevalent when the group started, that dementia is comparatively rare in LMICs. The experience of the 10/66 DRG has shown that descriptive epidemiological research can be important and impactful, where few data exist. Monitoring population trends in the prevalence and incidence of dementia may be our best chance to confirm hypotheses regarding modifiable risk factors of dementia.

People with Dementia in Sub-Saharan Africa: From Support to Abuse by Caregivers: Results of EPIDEMCA-FU Program in Congo

BACKGROUND/AIMS

Dementia is an emerging public health problem in sub-Saharan Africa (SSA). In SSA, the stigma suffered by people with dementia (PWD) can be strongly linked to pejorative social representations, interfering in social relationships with informal caregivers. The objective of the study was to analyze the consequences of social representations of PWD in social interactions with informal caregivers.

METHODS

A qualitative study was conducted in Republic of Congo among 93 interviewees. Nondirectional interviews were conducted in local languages and complemented by participating observations. The collected data were transcribed literally, synthesized, and then coded to allow extraction and organization of text segments.

RESULTS

Informal caregivers, daughters-in-laws, were considered as abusers and granddaughters as benevolent. The leaders of syncretic churches and traditional healers were the first therapeutic itineraries of PWD, due to pejorative social representations of disease. Of these, some PWD have appeared at front of a customary jurisdiction for accusations of witchcraft. Dementia, perceived as a mysterious disease by informal caregivers, wasn't medicalized by leaders of syncretic churches, traditional healers, nurses, or general practitioners. Conclusion: Stigma, generated by social representations, can change the patient's behavior and the one of informal caregivers, leading to time delay in the search for appropriate help.

Cognitive Function and Impairment in Older, Rural South African Adults: Evidence from "Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in Rural South Africa"

BACKGROUND/AIMS

We aimed to estimate the prevalence of cognitive impairment, and the sociodemographic and comorbid predictors of cognitive function among older, rural South African adults.

METHODS

Data were from a population-based study of 5,059 adults aged ≥40 years in rural South Africa in 2015. Cognitive impairment was defined as scoring ≤1.5 SDs below the mean composite time orientation and memory score, or requiring a proxy interview with "fair" or "poor" proxy-reported memory. Multiple linear regression estimated the sociodemographic and comorbid predictors of cognitive score, with multiplicative statistical interactions between each of age and sex with education.

RESULTS

Cognitive impairment increased with age, from 2% of those aged 40-44 (11/516) to 24% of those aged ≥75 years (214/899). The independent predictors of lower cognitive score were being older, female, unmarried, not working, having low education, low household wealth, and a history of cardiovascular conditions. Education modified the negative associations between female sex, older age, and cognitive function score.

CONCLUSIONS

The prevalence of cognitive impairment increased with age and is comparable to rates of dementia reported in other sub-Saharan African countries. Age and sex differences in cognitive function scores were minimized as education increased, potentially reflecting the power of even poor-quality education to improve cognitive reserve.

Prevalence of toxoplasmosis and its association with dementia in older adults in Central Africa: a result from the EPIDEMCA programme

OBJECTIVE

We aimed at estimating the seroprevalence of Toxoplasma gondii (T. gondii) infection in older adults living in Central Africa and investigating its association with dementia using data from the Epidemiology of Dementia in Central Africa (EPIDEMCA) programme.

METHODS

A cross-sectional multicentre population-based study was carried out among participants aged 73 (±7) years on average, living in rural and urban areas of the Central African Republic and the Republic of Congo between November 2011 and December 2012. Blood samples were collected from each consenting participant. The detection of anti-T. gondii immunoglobulin G antibodies was performed in 2014 in France using a commercially available ELISA kit. Participants were interviewed using a standardised questionnaire including sociodemographic characteristics. DSM-IV criteria were required for a diagnosis of dementia. Multivariate binary logistic regression models were used to assess the association between toxoplasmosis infection and dementia.

RESULTS

Among 1662 participants, the seroprevalence of toxoplasmosis was 63.0% (95% confidence interval (CI): 60.7-65.3) overall, 66.6% (95%CI: 63.4-69.8) in Central African Republic and 59.4% (95%CI: 56.1-62.7) in the Republic of Congo. In multivariate analyses, toxoplasmosis status was significantly associated with increasing age (P = 0.006), Republic of Congo (P = 0.002), urban area (P = 0.001) and previous occupation (P = 0.002). No associations between dementia and toxoplasmosis status or anti-T. gondii IgG titres were found.

CONCLUSION

Toxoplasma gondii infection was not associated with dementia among older adults in Central Africa. Our findings are consistent with previous studies and add to the knowledge on the relationship between T. gondii infection and neurological disorders.

Cognition, Health, and Well-Being in a Rural Sub-Saharan African Population

Cognitive health is an important dimension of well-being in older ages, but few studies have investigated the demography of cognitive health in sub-Saharan Africa's (SSA) growing population of mature adults (= persons age 45+). We use data from the Malawi Longitudinal Study of Families and Health (MLSFH) to document the age and gender patterns of cognitive health, the contextual and life-course correlates of poor cognitive health, and the understudied linkages between cognitive and physical/mental well-being. Surprisingly, the age-pattern of decline in cognitive health is broadly similar to that observed in the U.S. We also find that women have substantially worse cognitive health than men, and experience a steeper age-gradient in cognitive ability. Strong social ties and exposure to socially complex environments are associated with higher cognitive health, as is higher socioeconomic status. Poor cognitive health is associated with adverse social and economic well-being outcomes such as less nutrition intake, lower income, and reduced work efforts even in this subsistence agriculture context. Lower levels of cognitive health are also strongly associated with increased levels of depression and anxiety, and are associated with worse physical health measured through both self-reports and physical performance. Our findings suggest that cognition plays a key-but understudied-role in shaping late-life well-being in low-income populations.

Ankle-Brachial Index: An Ubiquitous Marker of Cognitive Impairment-The EPIDEMCA Study

Epidemiological research on the implication of atherosclerosis in the development of cognitive impairment is lacking in low- and middle-income countries, where two-thirds of the individuals affected by dementia live. Individuals aged ≥65 years living in urban and rural areas of 2 countries in Central Africa were invited. Demographic, clinical, and biological data were collected, and the ankle-brachial index (ABI) was measured. Cognitive impairment was defined according to the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) criteria. Among 1662 participants (age 72.9 years, 59.3% females), the prevalence of cognitive impairment was 13.6%, which is higher in individuals with ABI ≤ 0.90 and ABI ≥ 1.40 than those with 0.90 < ABI < 1.40 (20.1% and 17% vs 12%, P = .0024). Cognitive impairment was significantly associated with the factors such as age (odds ratio [OR]: 1.09; 95% confidence interval [CI]: 1.07-1.12, P < .0001), female gender (OR: 2.36, 95% CI: 1.59-3.49, P < .0001), smoking (OR: 1.54, 95% CI: 1.06-2.23, P = .0026), and low ABI (≤0.90; OR: 1.52, 95% CI: 1.03-2.25, P = .0359). The ABI, a ubiquitous marker of atherosclerosis, provides independent and incremental information on susceptibility to present with cognitive disorders.

Undernutrition and obesity among elderly people living in two cities of developing countries: Prevalence and associated factors in the EDAC study

BACKGROUND

Nutritional status among elderly people living in Sub-Saharan Africa is poorly studied, even though undernutrition and obesity are known to cause many complications and are risk factors for progression and death in several diseases. The aims of this study were to assess the nutritional status of the elderly in Central Africa and to study the factors associated with nutritional disorders (undernutrition and obesity).

METHODS

Two cross-sectional population-based studies were carried out in the capitals of Central African Republic (CAR) and Republic of Congo (ROC) between 2008 and 2009. Participants were aged ≥65 years old and underwent nutritional assessment including the following measurements: weight, height, body mass index (BMI), waist circumference (WC). Diet was also investigated. Nutritional status was defined according to the WHO BMI classification (<18.5 = undernutrition; ≥30 = obesity). Multinomial regression analysis was performed in order to identify factors associated with nutritional status.

RESULTS

990 elderly people underwent nutritional assessment (482 in CAR and 508 in ROC). Mean BMI was 22.7 ± 4.8 kg/m². The prevalence of undernutrition was 19.2% and was lower in ROC than in CAR (9.5% vs. 29.5%; p < 0.0001). The prevalence of obesity was 8.8% and was higher in ROC than in CAR (14.6% vs. 2.7%; p < 0.0001). The mean WC was 85.3 ± 28.4 cm. Adjusted on study site, increasing age (OR = 1.6 [95% CI: 1.1-2.3] for 75-84 years, OR = 2.6 [95% CI: 1.4-4.8] for 85+ years), occupation as farmer/breeder (OR = 2.2 [95% CI: 1.1-4.2]), smoking (OR = 1.71 [95% CI: 1.14-2.56]) and low sugar consumption (OR = 1.7 [95% CI: 1.1-2.7]) were positively associated with undernutrition whereas only female sex was positively associated with obesity (OR = 5.0 [95% CI: 2.2-11.0]).

CONCLUSIONS

The prevalence of undernutrition is high in the elderly population of these countries, in contrast to obesity. Undernutrition and obesity are associated with different socio-economic factors and food consumption. Simple nutritional advice could contribute to improving the nutritional status of elderly people in Central Africa.

Prevalence, awareness, treatment, and control of hypertension in older people in Central Africa: the EPIDEMCA study

Hypertension represents a major global health burden. While older individuals of African descent are at higher risk of hypertension in western countries, epidemiologic data on hypertension in older native Africans are scarce. We assessed the prevalence and the level of awareness and control of hypertension among older adults in Central Africa. A total of 1990 individuals aged 65 years and older from the Republic of Congo and the Central African Republic participated into a cross-sectional population-based survey. Hypertension was defined by self-reporting of ongoing treatment and/or systolic blood pressure/diastolic blood pressure at rest being ≥140 and/or 90 mm Hg. Controlled hypertension was defined as treated hypertension with systolic blood pressure <140 mm Hg and diastolic blood pressure <90 mm Hg. The overall prevalence of hypertension was 61.1%. Among hypertensive people, 46.7% were aware of their condition and 17.3% were treated. Among the latter, 23.8% had their hypertension controlled. Correlates of hypertension were increasing age and body mass index, living in the Republic of Congo, occupation other than employee, no tobacco use, sedentary lifestyle, and ≥3 meals a day. Our findings indicate a need for the implementation of public health policies to reduce hypertension in older Africans and to prevent the subsequent burden of cardiovascular diseases.

Dementia-associated mortality and its predictors among older adults in sub-Saharan Africa: results from a 2-year follow-up in Congo (the EPIDEMCA-FU study)

BACKGROUND

between 2011 and 2012, we carried out a study of dementia prevalence in central Africa throughout the EPIDEMCA (Epidemiology of Dementia in Central Africa) programme.

OBJECTIVE

to assess dementia-related mortality among Congolese older people from the EPIDEMCA study after 2 years of follow-up.

DESIGN

longitudinal population-based cohort study.

SETTING

Gamboma and Brazzaville, Republic of Congo.

METHODS

older participants were traced and interviewed in rural and urban Congo annually between 2012 and 2014. DSM-IV and NINCDS-ADRDA criteria were required for dementia diagnosis. Data on vital status were collected throughout the follow-up. Cox proportional hazards model was used to assess the link between baseline dementia diagnosis and mortality risk.

RESULTS

of 1,029 participants at baseline, 910 (88.4%) have a complete cognitive diagnosis. There were 791 participants (76.87%) with normal cognition, 56 (5.44%) with MCI and 63 (6.12%) with dementia. After 2 years of follow-up, 101 (9.8%) participants had died. Compared with participants with normal cognition, patients with dementia had 2.5 times higher mortality risk (HR = 2.53, 95% CI 1.42-4.49, P = 0.001). Among those with dementia, only clinical severity of dementia was associated with an additional increased mortality risk (HR = 1.91; CI 95%, 1.23-2.96; P = 0.004). Age (per 5-year increase), male sex and living in an urban area were independently associated with increased mortality risk across the full cohort.

CONCLUSION

among Congolese older adults, dementia is associated with increased mortality risk. Our results highlight the need for targeted health policies and strategies for dementia care in sub-Saharan Africa (SSA).

Association between mild cognitive impairment and dementia and undernutrition among elderly people in Central Africa: some results from the EPIDEMCA (Epidemiology of Dementia in Central Africa) programme

Several studies in Western countries have shown an association between cognitive disorders and low BMI or weight loss in elderly people. However, few data are available in Africa. We analysed the association between cognitive disorders and undernutrition among elderly people in Central Africa. A cross-sectional, multicentre, population-based study using a two-phase design was carried out in subjects aged 65 years and above in the Central African Republic (CAR) and the Republic of Congo (ROC). All subjects were interviewed using the Community Screening Interview for Dementia, and those with low performance were clinically assessed by a neurologist and underwent further psychometrical tests. Diagnostic and Statistical Manual-IV and Petersen's criteria were required for the diagnoses of dementia and mild cognitive impairment (MCI), respectively. Undernutrition was evaluated using mid-upper arm circumference (MUAC) < 24 cm, BMI < 18.5 kg/m(2) and arm muscular circumference (AMC) < 5th percentile. Multivariate binary logistic regression models were used to estimate the associations. In CAR, MCI was associated with MUAC < 24 cm (OR 0.7, 95% CI 0.4, 1.0) and dementia with BMI < 18.5 kg/m(2) (OR 2.3, 95% CI 1.6, 3.1), AMC < 5th percentile (OR 2.3, 95% CI 1.1, 4.6) and MUAC < 24 cm (OR 1.8, 95% CI 1.4, 2.4). In ROC, both MCI and dementia were associated with all markers of undernutrition, but only AMC < 5th percentile was significantly associated with MCI (OR 3.1, 95% CI 1.9, 4.8). In conclusion, cognitive disorders were associated with undernutrition. However, further studies are needed to elucidate the relationship between MCI and undernutrition in CAR.

Mutation in the 3'untranslated region of APP as a genetic determinant of cerebral amyloid angiopathy

Aβ-related cerebral amyloid angiopathy (CAA) is a major cause of primary non-traumatic brain hemorrhage. In families with an early onset of the disease, CAA can be due to amyloid precursor protein (APP) pathogenic variants or duplications. APP duplications lead to a ~1.5-fold increased APP expression, resulting in Aβ overproduction and deposition in the walls of leptomeningeal vessels. We hypothesized that rare variants in the 3'untranslated region (UTR) of APP might lead to APP overexpression in patients with CAA and no APP pathogenic variant or duplication. We performed direct sequencing of the whole APP 3'UTR in 90 patients with CAA and explored the functional consequences of one previously unreported variant. We identified three sequence variants in four patients, of which a two-base pair deletion (c.*331_*332del) was previously unannotated and absent from 175 controls of same ethnicity. This latter variant was associated with increased APP expression in vivo and in vitro. Bioinformatics and functional assays showed that the APP c.*331_*332del variant affected APP messenger RNA (mRNA) structure and binding of two microRNAs (miR-582-3p and miR-892b), providing a mechanism for the observed effects on APP expression. These results identify APP 3'UTR sequence variants as genetic determinants of Aβ-CAA.

Association between Stressful Life Events and Cognitive Disorders in Central Africa: Results from the EPIDEMCA Program

BACKGROUND

Stressful life events (SLEs) are considered potential risk factors for cognitive disorders. Our objective was to investigate the association between SLEs and cognitive disorders among the elderly people in Central Africa.

METHOD

A population-based study was conducted in the Central African Republic (CAR) and the Republic of Congo (ROC). Participants aged ≥65 were interviewed using the Community Screening Interview for Dementia. Those who performed poorly were clinically assessed by neurologists. DSM-IV and Petersen criteria were required for a diagnosis of dementia or mild cognitive impairment (MCI), respectively. SLEs were assessed through 18 questions about events that occurred during childhood, adulthood and late-life. Sociodemographic, vascular and psychological factors were also documented. Multivariate multinomial logistic regression models were used to estimate the associations.

RESULTS

MCI was positively associated with: the total number of SLEs (OR = 1.1, 95% CI: 1.0-1.2), the number of SLEs from the age of 65 (OR = 1.2, 95% CI: 1.0-1.3), the number of SLEs before the age of 16 among non-depressive participants (OR = 1.6, 95% CI: 1.2-2.2) and with a serious illness in a child experienced when the participant was aged 65 or more (OR = 2.8, 95% CI: 1.6-4.6). No association with dementia was observed.

CONCLUSION

SLEs were positively associated with MCI but not dementia. More comprehensive studies are needed to further investigate this relationship.

Prevalence of peripheral artery disease in the elderly population in urban and rural areas of Central Africa: the EPIDEMCA study

OBJECTIVE

Data on peripheral artery disease in Africa are sparse and limited to urban areas. Given the urban/rural socio-economical gradient in these countries, we sought to determine the prevalence and risk factors of peripheral artery disease in urban and rural areas of two countries in Central Africa.

METHODS

Individuals ≥65 years old living in two urban and rural areas of the Republic of Central Africa (ROC) and the Central African Republic (CAR) were invited. Demographic, clinical and biological data were collected. Ankle-brachial index ≤0.90 defined peripheral artery disease.

RESULTS

Among the 1871 participants (age 73 years, 62% female) the prevalence of peripheral artery disease was 14.8%, higher in ROC than in CAR (17.4% vs. 12.2%, p = 0.007) and higher in females than males (16.6% vs. 11.9%, p = 0.012). The prevalence of peripheral artery disease increased with age, respectively at 10.9%, 14.9%, 15.1% and 22.2% for age bands of 65-69, 70-74, 75-79 and 80+years (p < 0.001). Higher rates of peripheral artery disease were found in urban areas in ROC (20.7% vs. 14.4% in rural areas, p = 0.011), but not in CAR (11.5% vs. 12.9%, p = NS). In multivariate analysis, peripheral artery disease was significantly associated with age (odds ratio (OR): 1.03; p = 0.004), dyslipidaemia (OR: 1.88; p = 0.003), smoking (OR: 1.78; p = 0.003), obesity (OR: 1.98; p = 0.034) and underweight (OR: 1.49; p = 0.023). Regular alcohol drinking was associated with decreased risk of peripheral artery disease (OR: 0.73; p = 0.044).

CONCLUSION

The prevalence of peripheral artery disease in the elderly is high in Africa, especially in females. In ROC, with a higher urban-rural socio-economic gradient, peripheral artery disease is more frequent in the urban areas.

Is dependent personality disorder associated with mild cognitive impairment and dementia in Central Africa? A result from the EPIDEMCA programme

ABSTRACT Background: To date, no studies have examined the relationship between cognitive disorders and personality disorders. Our aim was to investigate the association between dependent personality disorder (DPD) and cognitive disorders in Central Africa. Methods: Between 2011 and 2012, a cross-sectional multicenter population-based study was carried out in rural and urban areas of the Central African Republic (CAR) and the Republic of Congo (ROC). Participants aged ≥65 years were interviewed using the Community Screening Interview for Dementia (CSI-D). Elderly people who performed poorly (CSI-D cognitive tests score or COGSCORE ≤ 24.5/30) were clinically assessed by neurologists and underwent further psychometric testing. The Diagnostic and Statistical Manual of Mental Disorders, 4th Edition and Petersen criteria were required for the diagnosis of dementia and mild cognitive impairment (MCI) respectively. DPD was assessed using the Personality Diagnostic Questionnaire-4+. Socio-demographic, vascular, and psychological factors were also documented. Multivariate multinomial logistic regression models were used to estimate the associations. Results: Of the 2,002 participants screened, 860 and 912 had data for cognitive status and DPD in CAR and ROC respectively. In fully adjusted models, DPD was significantly associated with MCI in ROC (Odds Ratio (OR) = 2.2, 95% CI: 1.0-4.7) and CAR (OR = 2.1, 95% CI: 1.1-4.0) and with dementia only in ROC (OR = 4.8, 95% CI: 2.0-11.7). Conclusions: DPD was associated with cognitive disorders among elderly people in Central Africa. This association should be confirmed in other contexts. This study paves the way for research on the association between personality and cognitive impairment in Africa.