Cohort Profile: The 10/66 study

Prevalence, aetiology, and service mapping of dementia in rural Uganda. Part of DEPEND Uganda (Dementia Epidemiology, unmet Need and co-Developing Solutions in Uganda)

Background

Dementia prevalence in low- and middle-income countries is increasing, yet epidemiological data from African populations remain scarce. Crucial risk factors differ in Africa from more intensively studied global areas, including a higher burden of cerebrovascular disease and HIV, but lower rates of other risk factors like physical inactivity.Understanding dementia aetiology in African settings has been limited by the expensive and invasive nature of biomarker testing. This study leverages developments in blood-based and retinal imaging biomarker technology to examine the drivers of dementia in older Ugandans.People with dementia have complex needs benefiting from multi-dimensional support. Understanding current services will allow identification of barriers and opportunities to strengthen support available to people with dementia and their families.

Methods

The study is nested within the General Population Cohort run by the Medical Research Council/Uganda Virus Research Institute & London School of Hygiene and Tropical Medicine Research Unit. All adults aged 60+ (around 1400) are undergoing brief cognitive screening.In Part 1, cohort participants are selected based on screening scores to undergo detailed cognitive assessment, using methods developed by the 10/66 Dementia Research Group. Part 2 is a case control study of people with and without dementia using antecedent data, questionnaires, physical assessment, retinal imaging, and Alzheimer's blood-based biomarkers. We will also compare disability, frailty, quality of life, and social engagement in people with and without dementia.Part 3 assesses current formal support structures for people with dementia through review of publicly available literature and expert interviews.

Conclusions

This is the first study in Africa using blood-based and retinal imaging biomarkers to examine pathological processes underlying dementia, and systematically map services available for people with dementia. This paves the way for effective policy strategies and further focused research regarding both dementia prevention and support for affected people and their families.

Cross-Sectional and Prospective Associations between Parkinsonism and Parkinson's Disease with Frailty in Latin America

BACKGROUND

Little is known about the relationship between parkinsonism or Parkinson's disease (PD) and frailty in Latin America.

OBJECTIVE

The study aimed to determine the cross-sectional and prospective associations between parkinsonism and PD with frailty in a large multi-country cohort in Latin America. Frailty was assessed using three different models to explore which definitions are more appropriate to screen for frailty in a PD population.

METHODS

12,865 older adults (aged ≥65 years) from the 10/66 population-based cohort study in six Latin American countries were analyzed. Logistic regression models assessed the cross-sectional association between parkinsonism/PD with baseline frailty. Individual country analyses were combined via fixed-effect meta-analysis. In non-frail participants who were followed up for 4 years, Cox proportional hazards regression models assessed the prospective association between parkinsonism/PD with incident frailty accounting for competing risk of mortality.

RESULTS

At baseline, the prevalence of parkinsonism and PD was 7% and 2%, respectively, and the prevalence of frailty varied across the three models with rates of 18% for frailty phenotype, 20% for frailty index and 30% for multidimensional frailty model. PD was associated with baseline and incident frailty after accounting for age, sex, and education: odds ratios and 95% confidence intervals (95% CI) for frailty were 2.49 (95% CIs 1.87-3.31), 2.42 (95% CIs 1.80-3.25), and 1.57 (95% CIs 1.16-2.21), and cause-specific hazard ratios were 1.66 (95% CIs 1.07-2.56), 1.78 (95% CIs 1.05-3.03), and 1.58 (95% CIs 0.91-2.74). Similar results were found for parkinsonism.

CONCLUSION

Parkinsonism and PD were cross-sectionally and prospectively associated with frailty in Latin America. Routine screening for frailty in PD patients may aid earlier detection of those at greater risk of adverse outcomes.

Social determinants of health but not global genetic ancestry predict dementia prevalence in Latin America

INTRODUCTION

Leveraging the nonmonolithic structure of Latin America, which represents a large variability in social determinants of health (SDoH) and high levels of genetic admixture, we aim to evaluate the relative contributions of SDoH and genetic ancestry in predicting dementia prevalence in Latin American populations.

METHODS

Community-dwelling participants aged 65 and older (N = 3808) from Cuba, Dominican Republic, Mexico, and Peru completed the 10/66 protocol assessments. Dementia was diagnosed using the cross-culturally validated 10/66 algorithm. Multivariate linear regression models adjusted for SDoH were used in the main analysis. This study used cross-sectional data from the 1066 population-based study.

RESULTS

Individuals with higher proportions of Native American (>70%) and African American (>70%) ancestry were more likely to exhibit factors contributing to worse SDoH, such as lower educational levels (p < 0.001), lower socioeconomic status (p < 0.001), and higher frequency of vascular risk factors (p < 0.001). After adjusting for measures of SDoH, there was no association between ancestry proportion and dementia probability, and ancestry proportions no longer significantly accounted for the variance in cognitive performance (African predominant p = 0.31 [-0.19, 0.59] and Native predominant p = 0.74 [-0.24, 0.33]).

DISCUSSION

The findings suggest that social and environmental factors play a more crucial role than genetic ancestry in predicting dementia prevalence in Latin American populations. This underscores the need for public health strategies and policies that address these social determinants to effectively reduce dementia risk in these communities.

HIGHLIGHTS

Countries in Latin America express a large variability in social determinants of health and levels of admixture. After adjustment for downstream societal factors linked to SDoH, genetic ancestry shows no link to dementia. Population ancestry profiles alone do not influence cognitive performance. SDoH are key drivers of racial disparities in dementia and cognitive performance.

A Systematic Review and Meta-Analysis on the Prevalence of Mild Cognitive Impairment and Dementia in Mexico

INTRODUCTION

Age remains one of the major risk factors for the onset of mild cognitive impairment (MCI) and dementia. Studies on the prevalence of these conditions in Mexico used different methods, tools, and populations with different health statuses. All these heterogeneous results may be a problem in identifying the true prevalence of MCI and dementia in Mexico. To our knowledge, there is not a systematic review available that presents essential figures on the prevalence of these conditions in Mexico. Therefore, we intend to access the maximum number of reports published on the topic and determine the prevalence of MCI and dementia in older Mexican adults.

METHODS

A systematic review using PubMed, Cochrane, Research Gate, Lilacs, and Scielo databases was performed. Meta-analysis of the prevalence of MCI and dementia was performed using a random-effects model and presented in a forest plot among cross-sectional, epidemiological, and pooled studies.

RESULTS

Sixteen articles were included. The overall prevalence of MCI of 18% (95% CI 0.10-0.27) was estimated from pooled information from 12 selected studies, in women 21% (95% CI 0.08-0.38) and in men 18% (95% CI 0.06-0.33). The overall prevalence of dementia of 10% (95% CI 0.06-0.14) was estimated from pooled information from 9 selected studies, in women 14% (95% CI 0.05-0.25) and in men 10% (95% CI 0.04-0.17).

CONCLUSION

Mexican older individuals have a similar prevalence of dementia and MCI as reported by international data; nevertheless, the prevalence is higher than in some Latin American countries. Mexico has particular issues that must be resolved, such as a lack of research in the southern regions of the country and the high incidence of comorbidities.

Prevalence and impact of neuropsychiatric symptoms in normal aging and neurodegenerative syndromes: A population-based study from Latin America

BACKGROUND

Neuropsychiatric symptoms (NPSs) are common in neurodegenerative diseases; however, little is known about the prevalence of NPSs in Hispanic populations.

METHODS

Using data from community-dwelling participants age 65 years and older enrolled in the 10/66 study (N = 11,768), we aimed to estimate the prevalence of NPSs in Hispanic populations with dementia, parkinsonism, and parkinsonism-dementia (PDD) relative to healthy aging. The Neuropsychiatric Inventory Questionnaire (NPI-Q) was used to assess NPSs.

RESULTS

NPSs were highly prevalent in Hispanic populations with neurodegenerative disease; approximately 34.3%, 56.1%, and 61.2% of the participants with parkinsonism, dementia, and PDD exhibited three or more NPSs, respectively. NPSs were the major contributor to caregiver burden.

DISCUSSION

Clinicians involved in the care of elderly populations should proactively screen for NPSs, especially in patients with parkinsonism, dementia, and PPD, and develop intervention plans to support families and caregivers. Highlights Neuropsychiatric symptoms (NPSs) are highly prevalent in Hispanic populations with neurodegenerative diseases. In healthy Hispanic populations, NPSs are predominantly mild and not clinically significant. The most common NPSs include depression, sleep disorders, irritability, and agitation. NPSs explain a substantial proportion of the variance in global caregiver burden.

Apolipoprotein E (APOE) genotype, dementia, and memory performance among Caribbean Hispanic versus US populations

INTRODUCTION

Apolipoprotein E (APOE) is considered the major susceptibility gene for developing Alzheimer's disease. However, the strength of this risk factor is not well established across diverse Hispanic populations.

METHODS

We investigated the associations among APOE genotype, dementia prevalence, and memory performance (immediate and delayed recall scores) in Caribbean Hispanics (CH), African Americans (AA), Hispanic Americans (HA) and non-Hispanic White Americans (NHW). Multivariable logistic regressions and negative binomial regressions were used to examine these associations by subsample.

RESULTS

Our final dataset included 13,516 participants (5198 men, 8318 women) across all subsamples, with a mean age of 74.8 years. Prevalence of APOE ε4 allele was similar in CHs, HAs, and NHWs (21.8%-25.4%), but was substantially higher in AAs (33.6%; P < 0.001). APOE ε4 carriers had higher dementia prevalence across all groups.

DISCUSSION

APOE ε4 was similarly associated with increased relative risk of dementia and lower memory performance in all subsamples.

In Caring for Older People in Low- and Middle-Income Countries, Do Older Caregivers Have a High Level of Care Burden and Psychological Morbidity Compared to Younger Caregivers?

Caregivers have become older as longevity increases. Caregiving for older people can cause burdens and psychological morbidity, which are the chronic stresses perceived by informal caregivers. This study aimed to compare the levels of care burden and psychological morbidity between older and younger caregivers in low- and middle-income countries. A cross-sectional survey was conducted in Cuba, the Dominican Republic, Peru, Venezuela, Mexico, Puerto Rico, and China. Data were collected by the 10/66 Dementia Research Group. The Zarit Burden Inventory was used to measure the levels of burden on caregivers. Psychological morbidity was assessed through the Self-Reporting Questionnaire. Data from 1348 households in which informal caregivers provided home care for one older person were included in the analysis. Multivariable logistic regression was used to investigate the effects of caregiver age upon care burden and psychological morbidity. A fixed-effect meta-analysis model was used to obtain a pooled estimate of the overall odds ratios of each country. The unadjusted and the adjusted model for potential covariates revealed no significant difference in care burden and psychological morbidity between older caregivers and younger caregivers. The adjusted pooled estimates, however, indicated a lower psychological morbidity among older caregivers (OR = 0.61, 95% CI: 0.41-0.93, I2 = 0.0%). The demographic implications of caregiver age may suggest different policy responses across low- and middle-income countries.

Risk of conversion from mild cognitive impairment to dementia in low- and middle-income countries: A systematic review and meta-analysis

Introduction

With no treatment for dementia, there is a need to identify high risk cases to focus preventive strategies, particularly in low- and middle-income countries (LMICs) where the burden of dementia is greatest. We evaluated the risk of conversion from mild cognitive ompairment (MCI) to dementia in LMICs.

Methods

Medline, Embase, PsycINFO, and Scopus were searched from inception until June 30, 2020. The search was restricted to observational studies, conducted in population-based samples, with at least 1 year follow-up. There was no restriction on the definition of MCI used as long as it was clearly defined. PROSPERO registration: CRD42019130958.

Results

Ten thousand six hundred forty-seven articles were screened; n = 11 retained. Of the 11 studies, most were conducted in China (n = 7 studies), with only two studies from countries classified as low income. A qualitative analysis of n = 11 studies showed that similar to high-income countries the conversion rate to dementia from MCI was variable (range 6 . 0%-44 . 8%; average follow-up 3 . 7 years [standard deviation = 1 . 2]). A meta-analysis of studies using Petersen criteria (n = 6 studies), found a pooled conversion rate to Alzheimer's disease (AD) of 23 . 8% (95% confidence interval = 15 . 4%-33.4%); approximately one in four people with MCI were at risk of AD in LMICs (over 3 . 0-5 . 8 years follow-up). Risk factors for conversion from MCI to dementia included demographic (e.g., age) and health (e.g., cardio-metabolic disease) variables.

Conclusions

MCI is associated with high, but variable, conversion to dementia in LMICs and may be influenced by demographic and health factors. There is a notable absence of data from low-income settings and countries outside of China. This highlights the urgent need for research investment into aging and dementia in LMIC settings. Being able to identify those individuals with cognitive impairment who are at highest risk of dementia in LMICs is necessary for the development of risk reduction strategies that are contextualized to these unique settings.

Dementia Risk Scores and Their Role in the Implementation of Risk Reduction Guidelines

Dementia prevention is a global health priority. In 2019, the World Health Organisation published its first evidence-based guidelines on dementia risk reduction. We are now at the stage where we need effective tools and resources to assess dementia risk and implement these guidelines into policy and practice. In this paper we review dementia risk scores as a means to facilitate this process. Specifically, we (a) discuss the rationale for dementia risk assessment, (b) outline some conceptual and methodological issues to consider when reviewing risk scores, (c) evaluate some dementia risk scores that are currently in use, and (d) provide some comments about future directions. A dementia risk score is a weighted composite of risk factors that reflects the likelihood of an individual developing dementia. In general, dementia risks scores have a wide range of implementations and benefits including providing early identification of individuals at high risk, improving risk perception for patients and physicians, and helping health professionals recommend targeted interventions to improve lifestyle habits to decrease dementia risk. A number of risk scores for dementia have been published, and some are widely used in research and clinical trials e.g., CAIDE, ANU-ADRI, and LIBRA. However, there are some methodological concerns and limitations associated with the use of these risk scores and more research is needed to increase their effectiveness and applicability. Overall, we conclude that, while further refinement of risk scores is underway, there is adequate evidence to use these assessments to implement guidelines on dementia risk reduction.

Intrinsic capacity and its associations with incident dependence and mortality in 10/66 Dementia Research Group studies in Latin America, India, and China: A population-based cohort study

BACKGROUND

The World Health Organization (WHO) has reframed health and healthcare for older people around achieving the goal of healthy ageing. The recent WHO Integrated Care for Older People (ICOPE) guidelines focus on maintaining intrinsic capacity, i.e., addressing declines in neuromusculoskeletal, vitality, sensory, cognitive, psychological, and continence domains, aiming to prevent or delay the onset of dependence. The target group with 1 or more declines in intrinsic capacity (DICs) is broad, and implementation may be challenging in less-resourced settings. We aimed to inform planning by assessing intrinsic capacity prevalence, by characterising the target group, and by validating the general approach-testing hypotheses that DIC was consistently associated with higher risks of incident dependence and death.

METHODS AND FINDINGS

We conducted population-based cohort studies (baseline, 2003-2007) in urban sites in Cuba, Dominican Republic, Puerto Rico, and Venezuela, and rural and urban sites in Peru, Mexico, India, and China. Door-knocking identified eligible participants, aged 65 years and over and normally resident in each geographically defined catchment area. Sociodemographic, behaviour and lifestyle, health, and healthcare utilisation and cost questionnaires, and physical assessments were administered to all participants, with incident dependence and mortality ascertained 3 to 5 years later (2008-2010). In 12 sites in 8 countries, 17,031 participants were surveyed at baseline. Overall mean age was 74.2 years, range of means by site 71.3-76.3 years; 62.4% were female, range 53.4%-67.3%. At baseline, only 30% retained full capacity across all domains. The proportion retaining capacity fell sharply with increasing age, and declines affecting multiple domains were more common. Poverty, morbidity (particularly dementia, depression, and stroke), and disability were concentrated among those with DIC, although only 10% were frail, and a further 9% had needs for care. Hypertension and lifestyle risk factors for chronic disease, and healthcare utilisation and costs, were more evenly distributed in the population. In total, 15,901 participants were included in the mortality cohort (2,602 deaths/53,911 person-years of follow-up), and 12,939 participants in the dependence cohort (1,896 incident cases/38,320 person-years). One or more DICs strongly and independently predicted incident dependence (pooled adjusted subhazard ratio 1.91, 95% CI 1.69-2.17) and death (pooled adjusted hazard ratio 1.66, 95% CI 1.49-1.85). Relative risks were higher for those who were frail, but were also substantially elevated for the much larger sub-groups yet to become frail. Mortality was mainly concentrated in the frail and dependent sub-groups. The main limitations were potential for DIC exposure misclassification and attrition bias.

CONCLUSIONS

In this study we observed a high prevalence of DICs, particularly in older age groups. Those affected had substantially increased risks of dependence and death. Most needs for care arose in those with DIC yet to become frail. Our findings provide some support for the strategy of optimising intrinsic capacity in pursuit of healthy ageing. Implementation at scale requires community-based screening and assessment, and a stepped-care intervention approach, with redefined roles for community healthcare workers and efforts to engage, train, and support them in these tasks. ICOPE might be usefully integrated into community programmes for detecting and case managing chronic diseases including hypertension and diabetes.

Development of a common scale for measuring healthy ageing across the world: results from the ATHLOS consortium

BACKGROUND

Research efforts to measure the concept of healthy ageing have been diverse and limited to specific populations. This diversity limits the potential to compare healthy ageing across countries and/or populations. In this study, we developed a novel measurement scale of healthy ageing using worldwide cohorts.

METHODS

In the Ageing Trajectories of Health-Longitudinal Opportunities and Synergies (ATHLOS) project, data from 16 international cohorts were harmonized. Using ATHLOS data, an item response theory (IRT) model was used to develop a scale with 41 items related to health and functioning. Measurement heterogeneity due to intra-dataset specificities was detected, applying differential item functioning via a logistic regression framework. The model accounted for specificities in model parameters by introducing cohort-specific parameters that rescaled scores to the main scale, using an equating procedure. Final scores were estimated for all individuals and converted to T-scores with a mean of 50 and a standard deviation of 10.

RESULTS

A common scale was created for 343 915 individuals above 18 years of age from 16 studies. The scale showed solid evidence of concurrent validity regarding various sociodemographic, life and health factors, and convergent validity with healthy life expectancy (r = 0.81) and gross domestic product (r = 0.58). Survival curves showed that the scale could also be predictive of mortality.

CONCLUSIONS

The ATHLOS scale, due to its reliability and global representativeness, has the potential to contribute to worldwide research on healthy ageing.

Italian version of the short 10/66 dementia diagnostic schedule: a validation study

OBJECTIVES

To determine the criterion and concurrent validity of the Italian version of the short 10/66 Dementia Diagnostic Schedule and algorithm in a sample of Italian native speakers, older adults.

DESIGN

A cross-sectional, validation study.

SETTING

The study was conducted with older adults living in the community and in nursing homes in the Canton of Ticino, Switzerland, and the Piedmont region in Italy between March and August 2019.

PARTICIPANTS

A convenience sample of 229 participants (69% females) were recruited. The eligibility criteria were being ≥60 years old and having an informant. The final sample included 74 participants (32%) with a previous clinical diagnosis of dementia and 155 (68%) cognitively healthy older adults.

PRIMARY AND SECONDARY OUTCOME MEASURES

The short version of 10/66 Dementia Diagnostic Schedule consists of the Community Screening Instrument for Dementia, the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) 10-word list learning task with delayed recall and the depression scale, Euro-Depression (EURO-D) scale. Disability was measured using the WHO Disability Assessment Schedule (WHO-DAS II).

RESULTS

The Italian version of the short 10/66 Dementia Diagnostic Schedule showed fair sensitivity (87%), specificity (61%) and agreement with the clinical diagnosis of dementia (kappa=0.40, area under the receiver operating characteristics curve=0.74). Older adults with dementia living in nursing homes had higher disability scores (WHO-DAS II mean=23.14, SE=1.29) than those living in the community (WHO-DAS II mean=7.08, SE=0.66). WHO-DAS II was positively correlated with the short version of the 10/66 dementia diagnosis (β=5.23, 95% CI 2.05 to 8.41).

CONCLUSIONS

In settings where lengthy diagnostic procedures are not feasible, the short 10/66 is a practical tool to identify dementia in older adults. Our findings extend evidence on the validity of the 10/66 dementia diagnostic algorithm to high-income countries, where epidemiological evidence on dementia and its impact is outdated.

Loneliness Among Older Adults in Latin America, China, and India: Prevalence, Correlates and Association With Mortality

Objectives: This study was designed to explore prevalence and correlates of self-reported loneliness and to investigate whether loneliness predicts mortality among older adults (aged 65 or above) in Latin America, China and India. Methods: The study investigated population-based cross-sectional (2003-2007) and longitudinal surveys (follow-up 2007-2010) from the 10/66 Dementia Research Group project. Poisson regression and Cox regression analyses were conducted to analyse correlates of loneliness and its association with mortality. Results: The standardised prevalence of loneliness varied between 25.3 and 32.4% in Latin America and was 18.3% in India. China showed a low prevalence of loneliness (3.8%). In pooled meta-analyses, there was robust evidence to support an association between loneliness and mortality across Latin American countries (HR = 1.13, 95% CI 1.01-1.26, I2 = 10.1%) and China (HR = 1.58, 95% CI 1.03-2.41), but there were no associations in India. Conclusion: Our findings suggest potential cultural variances may exist in the concept of loneliness in older age. The effect of loneliness upon mortality is consistent across different cultural settings excluding India. Loneliness should therefore be considered as a potential dimension of public health among older populations.

Sex differences in mortality: results from a population-based study of 12 longitudinal cohorts

BACKGROUND

Women generally have longer life expectancy than men but have higher levels of disability and morbidity. Few studies have identified factors that explain higher mortality in men. The aim of this study was to identify potential factors contributing to sex differences in mortality at older age and to investigate variation across countries.

METHODS

This study included participants age ≥ 50 yr from 28 countries in 12 cohort studies of the Ageing Trajectories of Health: Longitudinal Opportunities and Synergies (ATHLOS) consortium. Using a 2-step individual participant data meta-analysis framework, we applied Cox proportional hazards modelling to investigate the association between sex and mortality across different countries. We included socioeconomic (education, wealth), lifestyle (smoking, alcohol consumption), social (marital status, living alone) and health factors (cardiovascular disease, diabetes, mental disorders) as covariates or interaction terms with sex to test whether these factors contributed to the mortality gap between men and women.

RESULTS

The study included 179 044 individuals. Men had 60% higher mortality risk than women after adjustment for age (pooled hazard ratio [HR] 1.6; 95% confidence interval 1.5-1.7), yet the effect sizes varied across countries (I 2 = 71.5%, HR range 1.1-2.4). Only smoking and cardiovascular diseases substantially attenuated the effect size (by about 22%).

INTERPRETATION

Lifestyle and health factors may partially account for excess mortality in men compared with women, but residual variation remains unaccounted for. Variation in the effect sizes across countries may indicate contextual factors contributing to gender inequality in specific settings.

Race, genetic admixture and cognitive performance in the Cuban population

BACKGROUND

Population aging will lead to a dramatic increase in dementia prevalence, which will disproportionally affect racial minorities. The presence of racial differences in dementia prevalence has been widely reported in United States, but there are no relevant studies on this topic in low-middle income countries (LMIC).

METHODS

In a cross-sectional survey, 2,944 older Cubans were recruited at a community-based level aimed to identify the effects of self-identified race and genetic admixture on cognitive performance. Dementia diagnosis was established using 10/66 Dementia and DSM-IV criteria. APOE-ε4 genotype was determined in 2,511 (85%) and genetic admixture was completed for all dementia cases and in a randomly selected sample of cognitive healthy participants (218 dementia cases and 367 participants without dementia).

RESULTS

The overall prevalence of dementia was 8.7%, without large or statistically significant differences on dementia prevalence (p=0.12) by self-identified race. Mean cognitive scores were similar across racial groups (p=0.46). After controlling for age, sex and education, greater proportion of African ancestry was not associated with cognitive performance (p=0.17).

CONCLUSIONS

We found no evidence of an independent effect of self-identified race and/or population ancestry on dementia prevalence or cognitive performance. This suggests that observed differences in dementia prevalence among diverse populations may be driven primarily by social determinants of health.

Dementia Research in the Caribbean Hispanic Islands: Present Findings and Future Trends

During the last decade, the Caribbean Hispanic islands experienced accelerated demographic aging, representing the fastest aging region within Latin America. Age-related non-communicable diseases, including dementia, are now reported at high prevalence. The Caribbean islands share similar genetic ancestry, culture, migration patterns, and risk profiles, providing a unique setting to understand dementia in the Caribbean-Hispanics. This perspective article aimed to describe the impact of dementia in the Caribbean, at a local and regional level and reflect on research strategies to address dementia. We report on 10/66 project findings, described research projects and regional plans for the region. According to our results, the prevalence of dementia in the Caribbean is the highest in Latin America, with 11.7% in Dominican Republic, 11.6% in Puerto Rico, and 10.8% in Cuba. Preliminary data from new waves of the 10/66 study shows increasing numbers of dementia cases. Furthermore, dementia is expected to be one of the most serious medical and social issues confronted by Caribbean health systems. However, there is a scarcity of knowledge, awareness, and health services to deal with this public health crisis. In light of the new evidence, local and regional strategies are underway to better understand dementia trends for the region and develop policies aimed to decrease the impact of dementia. Implementation of our national plans is critical to deal with an aging population with high dementia rates. Current recommendations include emphasizing public health prevention campaigns to address modifiable risk factors and expand support to caregiver and family interventions.

A Brief Digital Cognitive Assessment for Detection of Cognitive Impairment in Cuban Older Adults

BACKGROUND

Rapid technological advances offer a possibility to develop cost-effective digital cognitive assessment tools. However, it is unclear whether these measures are suitable for application in populations from Low and middle-income countries (LMIC).

OBJECTIVE

To examine the accuracy and validity of the Brain Health Assessment (BHA) in detecting cognitive impairment in a Cuban population.

METHODS

In this cross-sectional study, 146 participants (cognitively healthy = 53, mild cognitive impairment (MCI) = 46, dementia = 47) were recruited at primary care and tertiary clinics. The main outcomes included: accuracy of the BHA and the Montreal Cognitive Assessment (MoCA) in discriminating between controls and cognitively impaired groups (MCI and dementia) and correlations between the BHA subtests of memory, executive functions, and visuospatial skills and criterion-standard paper-and-pencil tests in the same domains.

RESULTS

The BHA had an AUC of 0.95 (95% CI: 0.91-0.98) in discriminating between controls and cognitively impaired groups (MCI and dementia, combined) with 0.91 sensitivity at 0.85 specificity. In discriminating between control and MCI groups only, the BHA tests had an AUC of 0.94 (95% CI: 0.90-0.99) with 0.71 sensitivity at 0.85 specificity. Performance was superior to the MoCA across all diagnostic groups. Concurrent and discriminant validity analyses showed moderate to strong correlations between the BHA tests and standard paper-and-pencil measures in the same domain and weak correlations with standard measures in unrelated domains.

CONCLUSION

The BHA has excellent performance characteristics in detecting cognitive impairment including dementia and MCI in a Hispanic population in Cuba and outperformed the MoCA. These results support potential application of digital cognitive assessment for older adults in LMIC.

Risk Factors for Incident Dementia Among Older Cubans

Introduction: Little is known about risk factors of dementia in Latin American countries. We aimed to identify socio-demographic, health and lifestyle risk factors of incident dementia in Cuban older adults. Methods: Data were from 1,846 participants in the Cuban cohort of the 10/66 Dementia Research Group. Participants completed questionnaires, health examinations, and cognitive tests at baseline (2003-2006) and 4.5 years later (2007-2010). Associations between risk factors (baseline) and incident dementia (follow-up) were examined using logistic regression. Results: Just over 9% of participants developed dementia. Overall, older age and low physical activity were associated with incident dementia. In those 65-74 years of age, depression, stroke and low physical activity were associated with incident dementia. In those ≥75 years of age, low physical activity, never eating fish, and smoking were associated with incident dementia. Conclusions: Modifiable lifestyle factors play an important role in developing dementia in Cuban older adults. This knowledge opens up opportunities for preventive strategies.

Associations between Depression, Depressive Symptoms, and Incidence of Dementia in Latin America: A 10/66 Dementia Research Group Study

BACKGROUND

A growing body of evidence suggests that depression is related to dementia in older adults. Previous research has been done in high-income countries and there is a lack of studies in low- and middle income countries (LMICs).

OBJECTIVE

To examine the relationship between depressive symptoms and incidence of dementia in a population-based study of older adults in Latin America.

METHODS

The study is a part of the 10/66 Dementia Research Group's population survey and includes 11,472 older adults (baseline mean age 74 years) from Cuba, Dominican Republic, Mexico, Peru, Puerto Rico, and Venezuela. The baseline examinations were done in 2003-2007 and the follow-up examinations 4 years later. Semi-structured psychiatric interviews gave information about ICD-10 depression and sub-syndromal depression (i.e., ≥4 depressive symptoms) at baseline. Information on dementia were collected at the follow-up examination. Competing risk models analyzed the associations between depression and incidence of dementia and the final model were adjusted for age, sex, education, stroke, and diabetes. Separate analyses were conducted for each site and then meta-analyzed by means of fixed effect models.

RESULTS

At baseline, the prevalence of depression was 26.0% (n = 2,980): 5.4% had ICD-10 depression and 20.6% sub-syndromal depression. During the follow-up period, 9.3% (n = 862) developed dementia and 14.3% (n = 1,329) deceased. In the pooled analyses, both ICD-10 depression (adjusted sub-hazard ratio (sHR) 1.63, 95% confidence interval (CI) 1.26-2.11) and sub-syndromal depression (adjusted sHR 1.28, 95% CI: 1.09-1.51) were associated with increased incidence of dementia. The Higging I2 tests showed a moderate heterogeneity across the study sites.

CONCLUSION

Our findings suggest that late-life depression is associated with the incidence of dementia in LMICs in Latin America, which support results from earlier studies conducted in high-income countries.

Neighbourhood environment and dementia in older people from high-, middle- and low-income countries: results from two population-based cohort studies

BACKGROUND

A growing number of studies have explored how features of the neighbourhood environment can be related to cognitive health in later life. Yet few have focused on low- and middle-income countries and compared the results across different settings. The aim of this study is to investigate the cross-sectional associations between neighbourhood amenities and dementia in older people from high-, middle- and low-income countries.

METHODS

This study was based on two population-based cohort studies of people aged≥65: the Cognitive Function and Ageing Study II (CFAS II) in UK (N = 4955) and a subset of the 10/66 study in China, Dominican Republic and Mexico (N = 3386). In both cohorts, dementia was assessed using the Geriatric Mental State-Automated Geriatric Examination for Computer Assisted Taxonomy (GMS-AGECAT) algorithm. The 10/66 dementia diagnostic algorithm was also used as an additional criterion in the 10/66 study. Publicly accessible databases, Google Maps and Open Street Map, were used to obtain geographic information system data on distance to neighbourhood amenities, including lifestyle (cafés, libraries, movie theatres, parks), daily life (post offices, convenience stores), healthcare (hospitals, pharmacies) and percentages of local green and blue spaces within 400 and 800 m of participants' residences. Multilevel logistic regression was used to investigate the associations between these environmental features and dementia adjusting for sociodemographic factors and self-rated health.

RESULTS

Living far from daily life amenities was associated with higher odds of dementia in both CFAS II (1.47; 95% CI: 0.96, 2.24) and the 10/66 study (1.53; 95% CI: 1.15, 2.04), while living far from lifestyle (1.50; 95% CI: 1.13, 1.99) and healthcare amenities (1.32; 95% CI: 0.93, 1.87) was associated with higher odds of dementia only in the 10/66 study. A high availability of local green and blue spaces was not associated with dementia in either cohort yet living far from public parks was associated with lower odds of dementia in CFAS II (0.64; 95% CI: 0.41, 1.00).

CONCLUSIONS

The different relationships across cohorts may indicate a varying role for local amenities in diverse settings. Future research may investigate mechanisms related to these differences and social, cultural and historical influences on the interaction between neighbourhood amenities and older people.

The association between frailty and incidence of dementia in Beijing: findings from 10/66 dementia research group population-based cohort study

BACKGROUND

The relationship between frailty and dementia is unclear and there are very few population-based studies regarding this issue in China. The purpose of this study is to estimate the association between frailty and incident dementia in China, and to explore different effects of frailty established by three definitions of frailty on dementia incidence.

METHODS

A five-year prospective cohort study was carried out in 2022 participants aged 65 years and over in urban and rural sites in Beijing, China. The participants were interviewed by trained community primary health care workers from 2004 to 2009. Frailty was defined using modified Fried frailty phenotype, physical frailty definition, and multidimensional frailty definition. Dementia was diagnosed using the 10/66 dementia criterion for calculating cumulative incidence. Both competing risk regression models and Cox proportional hazards models were applied to examine the associations between frailty at baseline and five-year cumulative incidence of dementia.

RESULTS

At the end of follow-up the five-year cumulative incidence rates of dementia with frailty and without frailty defined by the modified Fried frailty were 21.0% and 9.6%, those defined by the physical frailty were 19.9% and 9.0%, and those defined by the multidimensional frailty were 22.8% and 8.9%, respectively. Compared with non-frail participants, frail people had a higher risk of incident dementia using multidimensional frailty definition after adjusting covariates based on competing risk regression model (HR = 1.47, 95% CI 1.01~2.17) and Cox proportional hazards model (HR = 1.56, 95% CI 1.07~2.26). The association between frailty and incident dementia was statistically significant in participants in the upper three quartiles of age (aged 68 years and over) using the multidimensional frailty definition based on the competing risk regression model (HR = 1.61, 95% CI 1.06~2.43) and Cox proportional hazard model (HR = 1.76, 95% CI 1.19~2.61).

CONCLUSIONS

Multidimensional frailty may play an inherent role in incident dementia, especially in the people aged over 68, which is significant for distinguishing high risk people and determining secondary prevention strategies for dementia patients.

Prediction of dementia risk in low-income and middle-income countries (the 10/66 Study): an independent external validation of existing models

BACKGROUND

To date, dementia prediction models have been exclusively developed and tested in high-income countries (HICs). However, most people with dementia live in low-income and middle-income countries (LMICs), where dementia risk prediction research is almost non-existent and the ability of current models to predict dementia is unknown. This study investigated whether dementia prediction models developed in HICs are applicable to LMICs.

METHODS

Data were from the 10/66 Study. Individuals aged 65 years or older and without dementia at baseline were selected from China, Cuba, the Dominican Republic, Mexico, Peru, Puerto Rico, and Venezuela. Dementia incidence was assessed over 3-5 years, with diagnosis according to the 10/66 Study diagnostic algorithm. Discrimination and calibration were tested for five models: the Cardiovascular Risk Factors, Aging and Dementia risk score (CAIDE); the Study on Aging, Cognition and Dementia (AgeCoDe) model; the Australian National University Alzheimer's Disease Risk Index (ANU-ADRI); the Brief Dementia Screening Indicator (BDSI); and the Rotterdam Study Basic Dementia Risk Model (BDRM). Models were tested with use of Cox regression. The discriminative accuracy of each model was assessed using Harrell's concordance (c)-statistic, with a value of 0·70 or higher considered to indicate acceptable discriminative ability. Calibration (model fit) was assessed statistically using the Grønnesby and Borgan test.

FINDINGS

11 143 individuals without baseline dementia and with available follow-up data were included in the analysis. During follow-up (mean 3·8 years [SD 1·3]), 1069 people progressed to dementia across all sites (incidence rate 24·9 cases per 1000 person-years). Performance of the models varied. Across countries, the discriminative ability of the CAIDE (0·52≤c≤0·63) and AgeCoDe (0·57≤c≤0·74) models was poor. By contrast, the ANU-ADRI (0·66≤c≤0·78), BDSI (0·62≤c≤0·78), and BDRM (0·66≤c≤0·78) models showed similar levels of discriminative ability to those of the development cohorts. All models showed good calibration, especially at low and intermediate levels of predicted risk. The models validated best in Peru and poorest in the Dominican Republic and China.

INTERPRETATION

Not all dementia prediction models developed in HICs can be simply extrapolated to LMICs. Further work defining what number and which combination of risk variables works best for predicting risk of dementia in LMICs is needed. However, models that transport well could be used immediately for dementia prevention research and targeted risk reduction in LMICs.

FUNDING

National Institute for Health Research, Wellcome Trust, WHO, US Alzheimer's Association, and European Research Council.

The association between, depression, anxiety, and mortality in older people across eight low- and middle-income countries: Results from the 10/66 cohort study

OBJECTIVES

Depression and anxiety are common mental disorders in later life. Few population-based studies have investigated their potential impacts on mortality in low- and middle-income countries (LMICs). The aim of this study is to examine the associations between depression, anxiety, their comorbidity, and mortality in later life using a population-based cohort study across eight LMICs.

METHODS

This analysis was based on the 10/66 cohort study including 15 991 people aged 65 years or above in Cuba, Dominican Republic, Venezuela, Mexico, Peru, Puerto Rico, China, and India, with an average follow-up time of 3.9 years. Subthreshold and clinical levels of depression were determined using EURO-D and ICD-10 criteria, and anxiety was based on Geriatric Mental State (GMS)-Automated Geriatric Examination for Computer Assisted Taxonomy (AGECAT). Cox proportional hazard modelling was used to estimate how having depression, anxiety, or both was associated with mortality adjusting for sociodemographic and health factors.

RESULTS

Participants with clinical depression (hazard ratio [HR]: 1.45; 95% CI, 1.24-1.70) and subthreshold anxiety (HR: 1.26; 95% CI, 1.15-1.38) had higher risk of mortality than those without the conditions after adjusting for sociodemographic factors and health conditions. Comorbidity of depression and anxiety was associated with a 30% increased risk of mortality but the effect sizes varied across countries (Higgins I2  = 58.8%), with the strongest association in India (HR: 1.99; 95% CI, 1.21-3.27).

CONCLUSIONS

Depression and anxiety appear to be associated with mortality in older people living in LMICs. Variation in effect sizes may indicate different barriers to health service access across countries. Future studies may investigate underlying mechanisms and identify potential interventions to reduce the impact of common mental disorders.

Healthy ageing and the prediction of mortality and incidence dependence in low- and middle- income countries: a 10/66 population-based cohort study

BACKGROUND

In the absence of a consensus on definition and measurement of healthy ageing, we created a healthy ageing index tallying with the functional ability framework provided by the World Health Organization. To create this index, we employed items of functional ability and intrinsic capacity. The current study aims to establish the predictive validity and discrimination properties of this healthy ageing index in settings in Latin American, part of the 10/66 cohort.

METHODS

Population-based cohort studies including 12,865 people ≥65 years old in catchment areas of Cuba, Dominican Republic, Venezuela, Mexico and Peru. We employed latent variable modelling to estimate the healthy ageing scores of each participant. We grouped participants according to the quintiles of the healthy ageing score distribution. Cox's proportional hazard models for mortality and sub-hazard (competing risks) models for incident dependence (i.e. needing care) were calculated per area after a median of 3.9 years and 3.7 years, respectively. Results were pooled together via fixed-effects meta-analysis. Our findings were compared with those obtained from self-rated health.

RESULTS

Participants with lowest levels, compared to participants with highest level of healthy ageing, had increased risk of mortality and incident dependence, even after adjusting for sociodemographic and health conditions (HR: 3.25, 95%CI: 2.63-4.02; sub-HR: 5.21, 95%CI: 4.02-6.75). Healthy ageing scores compared to self-rated health had higher population attributable fractions (PAFs) for mortality (43.6% vs 19.3%) and incident dependence (58.6% vs 17.0%), and better discriminative power (Harrell's c-statistic: mortality 0.74 vs 0.72; incident dependence 0.76 vs 0.70).

CONCLUSION

These results provide evidence that our healthy ageing index could be a valuable tool for prevention strategies as it demonstrated predictive and discriminative properties. Further research in other cultural settings will assist moving from a theoretical conceptualisation of healthy ageing to a more practical one.

Development of a healthy ageing index in Latin American countries - a 10/66 dementia research group population-based study

BACKGROUND

Our population is ageing and in 2050 more than one out of five people will be 60 years or older; 80% of whom will be living in a low-and-middle income country. Living longer does not entail living healthier; however, there is not a widely accepted measure of healthy ageing hampering policy and research. The World Health Organization defines healthy ageing as the process of developing and maintaining functional ability that will enable well-being in older age. We aimed to create a healthy ageing index (HAI) in a subset of six low-and-middle income countries, part of the 10/66 study, by using items of functional ability and intrinsic capacity.

METHODS

The study sample included residents 65-years old and over (n = 12,865) from catchment area sites in Cuba, Dominican Republic, Peru, Venezuela, Mexico and Puerto Rico. Items were collected by interviewing participants or key informants between 2003 and 2010. Two-stage factor analysis was employed and we compared one-factor, second-order and bifactor models. The psychometric properties of the index, including reliability, replicability, unidimensionality and concurrent convergent validity as well as measurement invariance per ethnic group and gender were further examined in the best fit model.

RESULTS

The bifactor model displayed superior model fit statistics supporting that a general factor underlies the various items but other subdomain factors are also needed. The HAI indicated excellent reliability (ω = 0.96, ωΗ = 0.84), replicability (H = 0.96), some support for unidimensionality (Explained Common Variance = 0.65) and some concurrent convergent validity with self-rated health. Scalar measurement invariance per ethnic group and gender was supported.

CONCLUSIONS

A HAI with excellent psychometric properties was created by using items of functional ability and intrinsic capacity in a subset of six low-and-middle income countries. Further research is needed to explore sub-population differences and to validate this index to other cultural settings.

Health-related quality-of-life assessment in dementia: Evidence of cross-cultural validity in Latin America

All health-related quality-of-life (HRQL) measures for dementia have been developed in high-income countries and none were validated for cross-cultural use. Yet, the global majority of people living with dementia reside in low- and middle-income countries. We therefore investigated the measurement invariance of a set of self- and informant-report HRQL measures developed in the United Kingdom when used in Latin America. Self-reported HRQL was obtained using (DEMQOL) at a memory assessment service in the United Kingdom (n = 868) and a population cohort study in Latin America (n = 417). Informant reports were collected using DEMQOL-Proxy at both sites (n = 909 and n = 495). Multiple-group confirmatory bifactor models for ordered categorical item responses were estimated to evaluate measurement invariance. Results support configural, metric, and scalar invariance for the concept of general HRQL in DEMQOL and DEMQOL-Proxy. The dominant impact of general HRQL on item responses was evident across U.K. English and Ibero American Spanish versions of DEMQOL (ωh = 0.87-0.90) and DEMQOL-Proxy (ωh = 0.88-0.89). Ratings of "positive emotion" did not show a major impact on general HRQL appraisal, particularly for Latin American respondents. Item information curves show that self- and informant-reports were highly informative about the presence rather than the absence of HRQL impairment. We found no major difference in conceptual meaning, sensitivity, and relevance of DEMQOL and DEMQOL-Proxy for older adults in the United Kingdom and Latin America. Further replication is needed for consensus over which HRQL measures are appropriate for making cross-national comparisons in global dementia research. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Depression and Incidence of Frailty in Older People From Six Latin American Countries

OBJECTIVE

Frailty and depression are highly comorbid conditions, but the casual direction is unclear and has not been explored in low- and middle-income countries. The aim of this study was to investigate the potential impact of depression on incident frailty in older people living in Latin America.

METHODS

This study was based on a population-based cohort of 12,844 people aged 65 or older from six Latin American countries (Cuba, Dominican Republic, Mexico, Venezuela, Puerto Rico, and Peru), part of the 10/66 cohort study. Two types of frailty measures were used: a modified Fried frailty phenotype and a multidimensional frailty criterion, which included measures from cognition, sensory, nutrition, and physical dimensions. Depression was assessed using EURO-D and International Classification of Diseases, Tenth Revision criteria. A competing risk model was used to examine the associations between baseline depression and incidence of frailty in the 3-5 years of follow-up, accounting for sociodemographic and health factors and the competing event of frailty-free death.

RESULTS

Depression was associated with a 59% increased hazard of developing frailty using the modified Fried phenotype (subdistribution hazard ratio [SHR]: 1.59; 95% confidence interval [CI]: 1.40, 1.80) and 19% for multidimensional frailty (SHR: 1.19; 95% CI: 1.06, 1.33) after adjusting for sociodemographic factors, physical impairments, and dementia. The associations between depression and the multidimensional frailty criteria were homogenous across all the sites (Higgins I² = 0%).

CONCLUSION

Depression may play a key role in the development of frailty. Pathways addressing the association between physical and mental health in older people need to be further investigated in future research.

Cardiovascular health and dementia incidence among older adults in Latin America: Results from the 10/66 study

OBJECTIVES

Growing evidence shows that cardiovascular health (CVH) is associated with brain health. Little is known about this topic among older adults in Latin America, where the number of people living with dementia is rising. This study aimed to assess the longitudinal association between CVH and dementia in six Latin American countries.

METHODS

We analyzed longitudinal data from the 10/66 study that included nondementia residents at baseline aged 65+ in six Latin American countries (n = 6447) and were followed up for 3 years. An index of modifiable CVH factors (ranging from 0 to 14) was calculated. Incident dementia was modeled using competing risk regression to adjust for risk of death.

RESULTS

The sample included 6.2% participants with poor (0-5), 81.0% with moderate (6-10), and 12.8% with ideal CVH (11-14). At follow-up, 9.4% had developed dementia and 13.1% had died. Compared with those with poor CVH, participants with moderate and ideal levels of CVH had a significantly lower risk of dementia in both the unadjusted (subhazard ratio for moderate, 0.77; ideal, 0.59) and adjusted models (moderate, 0.73; ideal, 0.66).

CONCLUSION

Moderate and ideal levels of CVH in old age may protect against dementia incidence. These findings may inform health promotion efforts within dementia national plans adopted recently in some Latin American countries.

Multimorbidity and care dependence in older adults: a longitudinal analysis of findings from the 10/66 study

BACKGROUND

In an ageing world facing an epidemic of chronic diseases, there is great interest in the burden of multimorbidity on individuals and caregivers, yet no studies have examined the longitudinal association between multimorbidity and care dependence in low and middle income countries. Mental and cognitive disorders are associated with dependence but little is known about their role in the pathway to dependence in the context of multimorbidity. This study aims to determine (1) the association of multimorbidity with the onset of care dependence in older adults, accounting for mortality and controlling for sociodemographic factors, and (2) the independent effects of physical multimorbidity, mental and cognitive disorders.

METHODS

A population-based cohort study of people aged 65 years and older in six countries in Latin America, and China. Data on chronic conditions and sociodemographic factors were collected at baseline. Multimorbidity was ascertained as a count of up to 15 mental, cognitive and physical health conditions. Dependence was ascertained through informant interviews at baseline and follow-up. We used competing risk regression to assess the association between multimorbidity and the onset of care dependence, acknowledging the possibility of dependence-free death. We also assessed the independent effects of physical multimorbidity and depression, anxiety and dementia individually.

RESULTS

12,965 participants, with no needs for care at baseline, were followed up for a median of 3.0-4.9 years. Each unit increase in multimorbidity count increased the cumulative risk of dependence by 20% in the fully adjusted model. Age was the only variable to confound this relationship. Physical multimorbidity was associated with only a modest increased risk of care dependence. Dementia, depression and anxiety were independently associated with incident care dependence at every level of physical multimorbidity, and depression and anxiety attenuated the effect of physical multimorbidity.

CONCLUSION

Multimorbidity consistently predicts care dependence with little variation between countries. Physical multimorbidity imparts a lower risk than multimorbidity with mental and cognitive disorders included. Mental and cognitive disorders independently increase the risk of care dependence. Comprehensive and holistic assessment of disorders of body, brain and mind can help to identify older people at high risk of care dependence.

Dependence- and Disability-Free Life Expectancy Across Eight Low- and Middle-Income Countries: A 10/66 Study

Objective: The objective of this study was to estimate healthy life expectancies in eight low- and middle-income countries (LMICs), using two indicators: disability-free life expectancy (DFLE) and dependence-free life expectancy (DepFLE). Method: Using the Sullivan method, healthy life expectancy was calculated based on the prevalence of dependence and disability from the 10/66 cohort study, which included 16,990 people aged 65 or above in China, Cuba, Dominican Republic, India, Mexico, Peru, Puerto Rico, and Venezuela, and country-specific life tables from the World Population Prospects 2017. Results: DFLE and DepFLE declined with older age across all sites and were higher in women than men. Mexico reported the highest DFLE at age 65 for men (15.4, SE = 0.5) and women (16.5, SE = 0.4), whereas India had the lowest with (11.5, SE = 0.3) in men and women (11.7, SE = 0.4). Discussion: Healthy life expectancy based on disability and dependency can be a critical indicator for aging research and policy planning in LMICs.

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.

Chronic Obstructive Pulmonary Disease and Risk of Dementia and Mortality in Lower to Middle Income Countries

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a major disease burden which accounts for 5% of all deaths globally, with most of those (>90%) occurring in lower to middle income countries (LMIC). It is also emerging as an important modifiable dementia risk factor.

OBJECTIVE

To address the knowledge gap surrounding the nature of the associations between COPD, dementia, and mortality, and the geographical variation of those associations in LMIC.

METHODS

Data from the 10/66 study surveying 15,394 participants (mean age 74 years, 62% female) across 8 countries was used to estimate the prevalence of self-reported COPD and its association with incident dementia and premature death. Proportional sub-hazards models using a cumulative incidence function were applied to identify the probability of incident dementia onset given the risk of premature death, with estimates pooled across countries via random effect meta-analysis.

RESULTS

Over the 3-year follow-up, almost 10% of participants developed dementia and 14% were deceased. COPD was not significantly associated with dementia incidence except in Cuba. However, fully adjusted models indicated that individuals with COPD were at a 28% increased risk of premature death, a trend present across most countries when analyzed individually.

CONCLUSION

The link between COPD and dementia is currently somewhat different and weaker in LMIC than in developed countries. This may be because premature death in the populations studied mask the development of clinical dementia. Given the global trend toward increased life expectancy, it is critical that the disease burden associated with COPD be addressed without delay if a further rise in dementia prevalence associated with COPD is to be avoided in LMIC.

Associations of Lifestyle Behaviour and Healthy Ageing in Five Latin American and the Caribbean Countries-A 10/66 Population-Based Cohort Study

Latin American and the Caribbean countries exhibit high life expectancy and projections show that they will experience the fastest growth of older people in the following years. As people live longer, it is important to maximise the opportunity to age healthily. We aimed to examine the associations of lifestyle behaviours with healthy ageing in Cuba, Dominican Republic, Peru, Mexico and Puerto Rico, part of the 10/66 study. Residents 65 years old and over (n = 10,900) were interviewed between 2003 and 2010. In the baseline survey, we measured four healthy behaviours: Physical activity, non-smoking, moderate drinking and fruits or vegetables consumption. Healthy ageing was conceptualised within the functional ability framework over a median of 4 years follow-up. Logistic models were calculated per country and then pooled together with fixed-effects meta-analysis. People engaging in physical activity and consuming fruits or vegetables had increased odds of healthy ageing in the follow-up (OR: 2.59, 95% CI: 2.20–3.03; OR: 1.24, 95% CI: 1.06–1.44, respectively). Compared with participants engaging in none or one healthy behaviour, the ORs of participants engaging in two, three or four healthy behaviours increased in a linear way (OR: 1.60, 95% CI: 1.40–1.84; OR: 2.29, 95% CI: 1.94–2.69; OR: 2.46, 95% CI: 1.54–3.92, respectively). Our findings highlight the importance of awareness of a healthy lifestyle behaviour among older people.

Neurological signs as early determinants of dementia and predictors of mortality among older adults in Latin America: a 10/66 study using the NEUROEX assessment

Background

Neurodegenerative processes in the elderly damage the brain, leading to progressive, incapacitating cognitive, behavioral, and motor dysfunctions which culminate in dementia. Fully manifest dementia is likely to be preceded by the presence of neurological signs, which could serve as early determinants of dementia and predictors of mortality. The aims of this study were to assess the construct validity of a neurological battery assessed among older adults living in Latin America, and to test the association of groups of neurological signs with dementia cross-sectionally, and mortality longitudinally.

Methods

The 10/66 Dementia Research Group collected information on neurological symptoms via the NEUROEX assessment in population based surveys of older adults living in low and middle-income countries. Data from 10,856 adults participating in the baseline assessment of the 10/66 study and living in Cuba, Dominican Republic, Peru, Venezuela and Mexico were analysed. Exploratory and confirmatory analysis were used to explore dimensionality of neurological symptoms. Poisson regression analyses were used to link groups of neurological signs with dementia at baseline. Cox hazard regression models were used to explore the predictive validity of neurological signs with mortality at follow up.

Results

Exploratory and confirmatory factor analyses revealed four dimensions of neurological signs, which are associated with lesions of specific brain regions. The identified factors showed consistency with groups of neurological signs such as frontal, cerebellar, extrapyramidal, and more generalized gait disturbance signs. Regression analyses revealed that all groups of neurological signs were positively associated with dementia at baseline and predicted mortality at follow up.

Conclusions

Our findings support the construct and predictive validity of the NEUROEX assessment, linking neurological and gait impairments with dementia at baseline, and with mortality at follow up among older adults living in five Latin American countries.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1167-4) contains supplementary material, which is available to authorized users.

Health and economic correlates of autonomy among older people in Peru, Mexico and China: The 10/66 INDEP study

Background: While autonomy is highlighted as central to older people’s wellbeing, there has been little empirical research to inform a measurement approach, support construct validity, or establish its determinants. We aimed to study the health and economic correlates of self-perceived autonomy among community-dwelling older people in Peru, Mexico and China, using a hypothesis-driven approach. Methods: Cross-sectional household surveys in urban and rural catchment areas in each country, comprising household, informant, and older person interviews, to elicit household income and older residents’ autonomy, unmet needs, and quality of life. Households, all with older residents, were selected from previous waves of the 10/66 Dementia Research Group’s comprehensive surveys of ageing and health. Results: Among 937 older respondents in 754 households, diminished autonomy was associated with older age, marital status, lower education, and lower household income. Physical, cognitive and mental morbidities, functional impairment and dependence were strongly and independently associated with diminished autonomy, explaining the effect of age. Controlling for these variables, an older person’s current total income was inversely associated with diminished autonomy (Count Ratio per fifth of total income 0.86, 95% CI 0.81-0.91). Autonomy was positively correlated with wellbeing and life satisfaction, supporting construct validity. Counter to hypotheses, less autonomy was associated with fewer unmet needs in rural sites. Conclusions: The effects of income insecurity, disability and dependence upon autonomy should be tested prospectively to confirm causal direction. Social pensions, and measures to support the rights of frail and dependent older people may be effective policy instruments for promoting autonomy. While the negative impact of diminished autonomy upon older people’s welfare is supported, the association in rural sites between more autonomy and more unmet needs should be further investigated; efforts to promote autonomy may need careful cultural nuancing, to support rather than subvert traditional family care systems.

Leg length, skull circumference, and the incidence of dementia in Latin America and China: A 10/66 population-based cohort study

Background

Adult leg length is influenced by nutrition in the first few years of life. Adult head circumference is an indicator of brain growth. Cross-sectional studies indicate inverse associations with dementia risk, but there have been few prospective studies.

Methods

Population-based cohort studies in urban sites in Cuba, Dominican Republic Puerto Rico and Venezuela, and rural and urban sites in Peru, Mexico and China. Sociodemographic and risk factor questionnaires were administered to all participants, and anthropometric measures taken, with ascertainment of incident dementia, and mortality, three to five years later.

Results

Of the original at risk cohort of 13,587 persons aged 65 years and over, 2,443 (18.0%) were lost to follow-up; 10,540 persons with skull circumference assessments were followed up for 40,466 person years, and 10,400 with leg length assessments were followed up for 39,954 person years. There were 1,009 cases of incident dementia, and 1,605 dementia free deaths. The fixed effect pooled meta-analysed adjusted subhazard ratio (ASHR) for leg length (highest vs. lowest quarter) was 0.80 (95% CI, 0.66–0.97) and for skull circumference was 1.02 (95% CI, 0.84–1.25), with no heterogeneity of effect between sites (I² = 0%). Leg length measurements tended to be shorter at follow-up, particularly for those with baseline cognitive impairment and dementia. However, leg length change was not associated with dementia incidence (ASHR, per cm 1.006, 95% CI 0.992–1.020), and the effect of leg length was little altered after adjusting for baseline frailty (ASHR 0.82, 95% CI 0.67–0.99). A priori hypotheses regarding effect modification by gender or educational level were not supported. However, the effect of skull circumference was modified by gender (M vs F ASHR 0.86, 95% CI 0.75–0.98), but in the opposite direction to that hypothesized with a greater protective effect of larger skull dimensions in men.

Conclusions

Consistent findings across settings provide quite strong support for an association between adult leg length and dementia incidence in late-life. Leg length is a relatively stable marker of early life nutritional programming, which may confer brain reserve and protect against neurodegeneration in later life through mitigation of cardiometabolic risk. Further clarification of these associations could inform predictive models for future dementia incidence in the context of secular trends in adult height, and invigorate global efforts to improve childhood nutrition, growth and development.

Reproductive period, endogenous estrogen exposure and dementia incidence among women in Latin America and China; A 10/66 population-based cohort study

BACKGROUND

Exposure to endogenous estrogen may protect against dementia, but evidence remains equivocal. Such effects may be assessed more precisely in settings where exogenous estrogen administration is rare. We aimed to determine whether reproductive period (menarche to menopause), and other indicators of endogenous estrogen exposure are inversely associated with dementia incidence.

METHODS

Population-based cohort studies of women aged 65 years and over in urban sites in Cuba, Dominican Republic, Puerto Rico and Venezuela, and rural and urban sites in Peru, Mexico and China. Sociodemographic and risk factor questionnaires were administered to all participants, including ages at menarche, birth of first child, and menopause, and parity, with ascertainment of incident 10/66 dementia, and mortality, three to five years later.

RESULTS

9,428 women participated at baseline, with 72-98% responding by site. The 'at risk' cohort comprised 8,466 dementia-free women. Mean age varied from 72.0 to 75.4 years, lower in rural than urban sites and in China than in Latin America. Mean parity was 4.1 (2.4-7.2 by site), generally higher in rural than urban sites. 6,854 women with baseline reproductive period data were followed up for 26,463 person years. There were 692 cases of incident dementia, and 895 dementia free deaths. Pooled meta-analysed fixed effects, per year, for reproductive period (Adjusted Sub-Hazard Ratio [ASHR] 1.001, 95% CI 0.988-1.015) did not support any association with dementia incidence, with no evidence for effect modification by APOE genotype. No association was observed between incident dementia and; ages at menarche, birth of first child, and menopause: nulliparity; or index of cumulative endogenous estrogen exposure. Greater parity was positively associated with incident dementia (ASHR 1.030, 95% CI 1.002-1.059, I2 = 0.0%).

CONCLUSIONS

We found no evidence to support the theory that natural variation in cumulative exposure to endogenous oestrogens across the reproductive period influences dementia incidence in late life.

The prevalence of dementia in a Portuguese community sample: a 10/66 Dementia Research Group study

Background

Dementia imposes a high burden of disease worldwide. Recent epidemiological studies in European community samples are scarce. In Portugal, community prevalence data is very limited. The 10/66 Dementia Research Group (DRG) population-based research programmes are focused in low and middle income countries, where the assessments proved to be culture and education fair. We applied the 10/66 DRG prevalence survey methodology in Portugal, where levels of illiteracy in older populations are still high.

Methods

A cross-sectional comprehensive one-phase survey was conducted of all residents aged 65 and over of two geographically defined catchment areas in Southern Portugal (one urban and one rural site). Nursing home residents were not included in the present study. Standardized 10/66 DRG assessments include a cognitive module, an informant interview and the Geriatric Mental State-AGECAT, providing data on dementia diagnosis and subtypes, mental disorders including depression, physical health, anthropometry, demographics, disability/functioning, health service utilization, care arrangements and caregiver strain.

Results

We interviewed 1405 old age participants (mean age 74.9, SD = 6.7 years; 55.5% women) after 313 (18.2%) refusals to participate.

The prevalence rate for dementia in community-dwellers was 9.23% (95% CI 7.80–10.90) using the 10/66 DRG algorithm and 3.65% (95% CI 2.97–4.97) using DSM-IV criteria. Pure Alzheimer’s disease was the most prevalent dementia subtype (41.9%). The prevalence of dementia was strongly age-dependent for both criteria, but there was no association with sex.

Conclusions

Dementia prevalence was higher than previously reported in Portugal. The discrepancy between prevalence according to the 10/66 DRG algorithm and the DSM-IV criteria is consistent with that observed in less developed countries; this suggests potential underestimation using the latter approach, although relative validity of these two approaches remains to be confirmed in the European context. We improved the evidence base to raise awareness and empower advocacy about dementia in Portugal, so that the complex needs of frail older people may be met in better ways.

Self-rated health and its association with mortality in older adults in China, India and Latin America-a 10/66 Dementia Research Group study

Background

empirical evidence from high-income countries suggests that self-rated health (SRH) is useful as a brief and simple outcome measure in public health research. However, in many low- and middle-income countries (LMIC) there is a lack of evaluation and the cross-cultural validity of SRH remains largely untested. This study aims to explore the prevalence of SRH and its association with mortality in older adults in LMIC in order to cross-culturally validate the construct of SRH.

Methods

population-based cohort studies including 16,940 persons aged ≥65 years in China, India, Cuba, Dominican Republic, Peru, Venezuela, Mexico and Puerto Rico in 2003. SRH was assessed by asking 'how do you rate your overall health in the past 30 days' with responses ranging from excellent to poor. Covariates included socio-demographic characteristics, use of health services and health factors. Mortality was ascertained through a screening of all respondents until 2007.

Results

the prevalence of good SRH was higher in urban compared to rural sites, except in China. Men reported higher SRH than women, and depression had the largest negative impact on SRH in all sites. Without adjustment, those with poor SRH showed a 142% increase risk of dying within 4 years compared to those with moderate SRH. After adjusting for all covariates, those with poor SRH still showed a 43% increased risk.

Conclusion

our findings support the use of SRH as a simple measure in survey settings to identify vulnerable groups and evaluate health interventions in resource-scares settings.

Neuropsychiatric symptoms as risk factors of dementia in a Mexican population: A 10/66 Dementia Research Group study

Introduction

Cognitive and/or memory impairment are the main clinical markers currently used to identify subjects at risk of developing dementia. This study aimed to explore the relationship between the presence of neuropsychiatric symptoms and dementia incidence.

Methods

We analyzed the association between neuropsychiatric symptoms and incident dementia in a cohort of 1355 Mexican older adults from the general population over 3 years of follow-up, modeling cumulative incidence ratios using Poisson models.

Results

Five neuropsychiatric symptoms were associated with incident dementia: delusions, hallucinations, anxiety, aberrant motor behavior, and depression. The simultaneous presence of two symptoms had a relative risk, adjusted for mild cognitive impairment, diabetes, indicators of cognitive function, and sociodemographic factors, of 1.9 (95% confidence interval, 1.2–2.9), whereas the presence of three to five, similarly adjusted, had a relative risk of 3.0 (95% confidence interval, 1.9–4.8).

Discussion

Neuropsychiatric symptoms are common in predementia states and may independently contribute as risk factors for developing dementia.

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Not only cognitive impairment and cognitive features are useful in identifying older adults at risk for developing dementia.

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Of the 12 neuropsychiatric symptoms evaluated, 5 were associated with incident dementia (delusions, hallucinations, depression, anxiety, and aberrant motor behavior) in a 3-year follow-up.

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The evaluation of neuropsychiatric symptoms, along with other simple, practical, and inexpensive features, may be useful in identifying subjects at risk of dementia in community health settings and by general practitioners.

A journey without maps-Understanding the costs of caring for dependent older people in Nigeria, China, Mexico and Peru

PURPOSE OF THE STUDY

Populations in Latin America, Asia and sub-Saharan Africa are rapidly ageing. The extent to which traditional systems of family support and security can manage the care of increased numbers of older people with chronic health problems is unclear. Our aim was to explore the social and economic effects of caring for an older dependent person, including insight into pathways to economic vulnerability.

DESIGN & METHODS

We carried out a series of household case studies across urban and rural sites in Peru, Mexico, China and Nigeria (n = 24), as part of a cross-sectional study, nested within the 10/66 Dementia Research Group cohort. Case studies consisted of in-depth narrative style interviews (n = 60) with multiple family members, including the older dependent person.

RESULTS

Governments were largely uninvolved in the care and support of older dependent people, leaving families to negotiate a 'journey without maps'. Women were de facto caregivers but the traditional role of female relative as caregiver was beginning to be contested. Household composition was flexible and responsive to changing needs of multiple generations but family finances were stretched.

IMPLICATIONS

Governments are lagging behind sociodemographic and social change. There is an urgent need for policy frameworks to support and supplement inputs from families. These should include community-based and residential care services, disability benefits and carers allowances. Further enhancement of health insurance schemes and scale-up of social pensions are an important component of bolstering the security of dependent older people and supporting their continued social and economic participation.