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.

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 cohort study of the effects of older adult care dependence upon household economic functioning, in Peru, Mexico and China.

BACKGROUND: While links between disability and poverty are well established, there have been few longitudinal studies to clarify direction of causality, particularly among older adults in low and middle income countries. We aimed to study the effect of care dependence among older adult residents on the economic functioning of their households, in catchment area survey sites in Peru, Mexico and China. METHODS: Households were classified from the evolution of the needs for care of older residents, over two previous community surveys, as 'incident care', 'chronic care' or 'no care', and followed up three years later to ascertain economic outcomes (household income, consumption, economic strain, satisfaction with economic circumstances, healthcare expenditure and residents giving up work or education to care). RESULTS: Household income did not differ between household groups. However, income from paid work (Pooled Count Ratio pCR 0.88, 95% CI 0.78-1.00) and government transfers (pCR 0.80, 95% CI 0.69-0.93) were lower in care households. Consumption was 12% lower in chronic care households (pCR 0.88, 95% CI 0.77-0.99). Household healthcare expenditure was higher (pCR 1.55, 95% CI 1.26-1.90), and catastrophic healthcare spending more common (pRR 1.64, 95% CI 1.64-2.22) in care households. CONCLUSIONS: While endogeneity cannot be confidently excluded as an explanation for the findings, this study indicates that older people's needs for care have a discernable impact on household economics, controlling for baseline indicators of long-term economic status. Although living, typically, in multigenerational family units, older people have not featured prominently in global health and development agendas. Population ageing will rapidly increase the number of households where older people live, and their societal significance. Building sustainable long-term care systems for the future will require some combination of improved income security in old age; incentivisation of informal care through compensation for direct and opportunity costs; and development of community care services to support, and, where necessary, supplement or substitute the central role of informal caregivers.

The Prevalence and Correlates of Frailty in Urban and Rural Populations in Latin America, China, and India: A 10/66 Population-Based Survey.

BACKGROUND: There have been few cross-national studies of the prevalence of the frailty phenotype conducted among low or middle income countries. We aimed to study the variation in prevalence and correlates of frailty in rural and urban sites in Latin America, India, and China. METHODS: Cross-sectional population-based catchment area surveys conducted in 8 urban and 4 rural catchment areas in 8 countries; Cuba, Dominican Republic, Puerto Rico, Venezuela, Peru, Mexico, China, and India. We assessed weight loss, exhaustion, slow walking speed, and low energy consumption, but not hand grip strength. Therefore, frailty phenotype was defined on 2 or more of 4 of the usual 5 criteria. RESULTS: We surveyed 17,031 adults aged 65 years and over. Overall frailty prevalence was 15.2% (95% confidence inteval 14.6%-15.7%). Prevalence was low in rural (5.4%) and urban China (9.1%) and varied between 12.6% and 21.5% in other sites. A similar pattern of variation was apparent after direct standardization for age and sex. Cross-site variation in prevalence of frailty indicators varied across the 4 indicators. Controlling for age, sex, and education, frailty was positively associated with older age, female sex, lower socioeconomic status, physical impairments, stroke, depression, dementia, disability and dependence, and high healthcare costs. DISCUSSION: There was substantial variation in the prevalence of frailty and its indicators across sites in Latin America, India, and China. Culture and other contextual factors may impact significantly on the assessment of frailty using questionnaire and physical performance-based measures, and achieving cross-cultural measurement invariance remains a challenge. CONCLUSIONS: A consistent pattern of correlates was identified, suggesting that in all sites, the frailty screen could identify older adults with multiple physical, mental, and cognitive morbidities, disability and needs for care, compounded by socioeconomic disadvantage and catastrophic healthcare spending.

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.

The economic status of older people's households in urban and rural settings in Peru, Mexico and China: a 10/66 INDEP study cross-sectional survey.

Few data are available from middle income countries regarding economic circumstances of households in which older people live. Many such settings have experienced rapid demographic, social and economic change, alongside increasing pension coverage. Population-based household surveys in rural and urban catchment areas in Peru, Mexico and China. Participating households were selected from all households with older residents. Descriptive analyses were weighted back for sampling fractions and non-response. Household income and consumption were estimated from a household key informant interview. 877 Household interviews (3177 residents). Response rate 68 %. Household income and consumption correlated plausibly with other economic wellbeing indicators. Household Incomes varied considerably within and between sites. While multigenerational households were the norm, older resident's incomes accounted for a high proportion of household income, and older people were particularly likely to pool income. Differences in the coverage and value of pensions were a major source of variation in household income among sites. There was a small, consistent inverse association between household pension income and labour force participation of younger adult co-residents. The effect of pension income on older adults' labour force participation was less clear-cut. Historical linkage of social protection to formal employment may have contributed to profound late-life socioeconomic inequalities. Strategies to formalise the informal economy, alongside increases in the coverage and value of non-contributory pensions and transfers would help to address this problem.

The Prevalence, Correlates, Detection and Control of Diabetes among Older People in Low and Middle Income Countries. A 10/66 Dementia Research Group Population-Based Survey.

BACKGROUND: Little is known of the epidemiology of diabetes among older people in low and middle income countries. We aimed to study and compare prevalence, social patterning, correlates, detection, treatment and control of diabetes among older people in Latin America, India, China and Nigeria. METHODS: Cross-sectional surveys in 13 catchment area sites in nine countries. Diagnosed diabetes was assessed in all sites through self-reported diagnosis. Undiagnosed diabetes was assessed in seven Latin American sites through fasting blood samples (glucose > = 7 mmol/L). RESULTS: Total diabetes prevalence in catchment sites in Cuba (prevalence 24.2%, SMR 116), Puerto Rico (43.4%, 197), and urban (27.0%, 125), and rural Mexico (23.7%, 111) already exceeds that in the USA, while that in Venezuela (20.9%, 100) is similar. Diagnosed diabetes prevalence varied very widely, between low prevalences in sites in rural China (0.9%), rural India (6.6%) and Nigeria (6.0%). and 32.1% in Puerto Rico, explained mainly by access to health services. Treatment coverage varied substantially between sites. Diabetes control (40 to 61% of those diagnosed) was modest in the Latin American sites where this was studied. Diabetes was independently associated with less education, but more assets. Hypertension, central obesity and hypertriglyceridaemia, but not hypercholesterolaemia were consistently associated with total diabetes. CONCLUSIONS: Diabetes prevalence is already high in most sites. Identifying undiagnosed cases is essential to quantify population burden, particularly in least developed settings where diagnosis is uncommon. Metabolic risk factors and associated lifestyles may play an important part in aetiology, but this requires confirmation with longitudinal data. Given the high prevalence among older people, more population research is indicated to quantify the impact of diabetes, and to monitor the effect of prevention and health system strengthening on prevalence, treatment and control.

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

BACKGROUND: In countries with high incomes, frailty indicators predict adverse outcomes in older people, despite a lack of consensus on definition or measurement. We tested the predictive validity of physical and multidimensional frailty phenotypes in settings in Latin America, India, and China. METHODS: Population-based cohort studies were conducted in catchment area sites in Cuba, Dominican Republic, Venezuela, Mexico, Peru, India, and China. Seven frailty indicators, namely gait speed, self-reported exhaustion, weight loss, low energy expenditure, undernutrition, cognitive, and sensory impairment were assessed to estimate frailty phenotypes. Mortality and onset of dependence were ascertained after a median of 3.9 years. RESULTS: Overall, 13,924 older people were assessed at baseline, with 47,438 person-years follow-up for mortality and 30,689 for dependence. Both frailty phenotypes predicted the onset of dependence and mortality, even adjusting for chronic diseases and disability, with little heterogeneity of effect among sites. However, population attributable fractions (PAF) summarising etiologic force were highest for the aggregate effect of the individual indicators, as opposed to either the number of indicators or the dichotomised frailty phenotypes. The aggregate of all seven indicators provided the best overall prediction (weighted mean PAF 41.8 % for dependence and 38.3 % for mortality). While weight loss, underactivity, slow walking speed, and cognitive impairment predicted both outcomes, whereas undernutrition predicted only mortality and sensory impairment only dependence. Exhaustion predicted neither outcome. CONCLUSIONS: Simply assessed frailty indicators identify older people at risk of dependence and mortality, beyond information provided by chronic disease diagnoses and disability. Frailty is likely to be multidimensional. A better understanding of the construct and pathways to adverse outcomes could inform multidimensional assessment and intervention to prevent or manage dependence in frail older people, with potential to add life to years, and years to life.

Psychometric properties of EURO-D, a geriatric depression scale: a cross-cultural validation study.

BACKGROUND: Many of the assessment tools used to study depression among older people are adaptations of instruments developed in other cultural setting. There is a need to validate those instruments in low and middle income countries (LMIC). METHODS: A one-phase cross-sectional survey of people aged [greater than or equal to] 65 years from LMIC. EURO-D was checked for psychometric properties. Calibration with clinical diagnosis was made using ICD-10. Optimal cutpoint was determined. Concurrent validity was assessed measuring correlations with WHODAS 2.0. RESULTS: 17,852 interviews were completed in 13 sites from nine countries. EURO-D constituted a hierarchical scale in most sites. The most commonly endorsed symptom in Latin American sites was depression; in China was sleep disturbance and tearfulness; in India, irritability and fatigue and in Nigeria loss of enjoyment. Two factor structure (affective and motivation) were demonstrated. Measurement invariance was demonstrated among Latin American and Indian sites being less evident in China and Nigeria. At the 4/5 cutpoint, sensitivity for ICD-10 depressive episode was 86% or higher in all sites and specificity exceeded 84% in all Latin America and Chinese sites. Concurrent validity was supported, at least for Latin American and Indian sites. CONCLUSIONS: There is evidence for the cross-cultural validity of the EURO-D scale at Latin American and Indian settings and its potential applicability in comparative epidemiological studies.

Dementia incidence and mortality in middle-income countries, and associations with indicators of cognitive reserve: a 10/66 Dementia Research Group population-based cohort study.

BACKGROUND: Results of the few cohort studies from countries with low incomes or middle incomes suggest a lower incidence of dementia than in high-income countries. We assessed incidence of dementia according to criteria from the 10/66 Dementia Research Group and Diagnostic and Statistical Manual of Mental Disorders (DSM) IV, the effect of dementia at baseline on mortality, and the independent effects of age, sex, socioeconomic position, and indicators of cognitive reserve. METHODS: We did a population-based cohort study of all people aged 65 years and older living in urban sites in Cuba, the Dominican Republic, and Venezuela, and rural and urban sites in Peru, Mexico, and China, with ascertainment of incident 10/66 and DSM-IV dementia 3-5 years after cohort inception. We used questionnaires to obtain information about age in years, sex, educational level, literacy, occupational attainment, and number of household assets. We obtained information about mortality from all sites. For participants who had died, we interviewed a friend or relative to ascertain the likelihood that they had dementia before death. FINDINGS: 12,887 participants were interviewed at baseline. 11,718 were free of dementia, of whom 8137 (69%) were reinterviewed, contributing 34,718 person-years of follow-up. Incidence for 10/66 dementia varied between 18·2 and 30·4 per 1000 person-years, and were 1·4-2·7 times higher than were those for DSM-IV dementia (9·9-15·7 per 1000 person-years). Mortality hazards were 1·56-5·69 times higher in individuals with dementia at baseline than in those who were dementia-free. Informant reports suggested a high incidence of dementia before death; overall incidence might be 4-19% higher if these data were included. 10/66 dementia incidence was independently associated with increased age (HR 1·67; 95% CI 1·56-1·79), female sex (0·72; 0·61-0·84), and low education (0·89; 0·81-0·97), but not with occupational attainment (1·04; 0·95-1·13). INTERPRETATION: Our results provide supportive evidence for the cognitive reserve hypothesis, showing that in middle-income countries as in high-income countries, education, literacy, verbal fluency, and motor sequencing confer substantial protection against the onset of dementia. FUNDING: Wellcome Trust Health Consequences of Population Change Programme, WHO, US Alzheimer's Association, FONACIT/ CDCH/ UCV.

Prevalence, distribution, and impact of mild cognitive impairment in Latin America, China, and India: a 10/66 population-based study.

BACKGROUND: Rapid demographic ageing is a growing public health issue in many low- and middle-income countries (LAMICs). Mild cognitive impairment (MCI) is a construct frequently used to define groups of people who may be at risk of developing dementia, crucial for targeting preventative interventions. However, little is known about the prevalence or impact of MCI in LAMIC settings. METHODS AND FINDINGS: Data were analysed from cross-sectional surveys established by the 10/66 Dementia Research Group and carried out in Cuba, Dominican Republic, Peru, Mexico, Venezuela, Puerto Rico, China, and India on 15,376 individuals aged 65+ without dementia. Standardised assessments of mental and physical health, and cognitive function were carried out including informant interviews. An algorithm was developed to define Mayo Clinic amnestic MCI (aMCI). Disability (12-item World Health Organization disability assessment schedule [WHODAS]) and informant-reported neuropsychiatric symptoms (neuropsychiatric inventory [NPI-Q]) were measured. After adjustment, aMCI was associated with disability, anxiety, apathy, and irritability (but not depression); between-country heterogeneity in these associations was only significant for disability. The crude prevalence of aMCI ranged from 0.8% in China to 4.3% in India. Country differences changed little (range 0.6%-4.6%) after standardization for age, gender, and education level. In pooled estimates, aMCI was modestly associated with male gender and fewer assets but was not associated with age or education. There was no significant between-country variation in these demographic associations. CONCLUSIONS: An algorithm-derived diagnosis of aMCI showed few sociodemographic associations but was consistently associated with higher disability and neuropsychiatric symptoms in addition to showing substantial variation in prevalence across LAMIC populations. Longitudinal data are needed to confirm findings-in particular, to investigate the predictive validity of aMCI in these settings and risk/protective factors for progression to dementia; however, the large number affected has important implications in these rapidly ageing settings.

Chronic diseases among older people and co-resident psychological morbidity: a 10/66 Dementia Research Group population-based survey.

BACKGROUND: This is the first study to investigate the associations between chronic health conditions of older people and their impact on co-resident psychological morbidity using population-based samples in low and middle income countries (LAMICs). METHODS: Single-phase cross-sectional catchment area surveys were undertaken in urban sites in Cuba, Dominican Republic and Venezuela, and in rural and urban catchment areas in Mexico, Peru, India and China. All residents aged 65 years and over were interviewed with a co-resident key informant. Exposures were structured clinical diagnoses (10/66 and DSM-IV dementia and ICD-10 depression), self-reported diagnosis (stroke) and physical impairments. Mediating variables were dependence and disability (WHODAS 2.0), and the outcome was co-resident psychological morbidity assessed using SRQ-20. RESULTS: Poisson regression analysis was used to estimate the prevalence ratios (PRs) for the associations between health conditions and psychological morbidity in each site, and meta-analysis was used to pool the estimates. 11,988 pairs comprising a participant and a co-resident informant were included in the analysis. After meta-analysis, independent effects were noted for depression (PR2.11; 95% CI 1.82-2.45), dementia (PR 1.98; 95% CI 1.72-2.28), stroke (PR 1.42; 95% CI 1.17-1.71) and physical impairments (PR 1.17; 95% CI 1.13-1.21). The effects were partly mediated through disability and dependence. The mean population attributable fraction of total chronic conditions was 30.1%. CONCLUSION: The prevalence of co-resident psychological morbidity is higher among co-residents of older people with chronic conditions. This effect was prominent for, but not confined to, depression and dementia. Attention needs to be directed to chronic conditions.

Helping carers to care: the 10/66 dementia research group's randomized control trial of a caregiver intervention in Peru / Ajudando os cuidadores a cuidar: uma prova clínica randomizada da intervenção para o cuidador desenvolvida pelo grupo 10/66 no Peru

OBJECTIVE: There is a need, in the absence of formal services, to design interventions aimed at improving the lives of people with dementia and their families. This study tested the effectiveness of the 10/66 caregiver intervention among people with dementia and their caregivers in Lima, Peru. METHOD: Design/participants: a randomized controlled trial was performed involving 58 caregivers of people with dementia that received the intervention in the beginning of the trial (n = 29) or six months later (n = 29). The intervention consisted of three modules: 1) assessment (one session); 2) basic education about dementia (two sessions); and 3) training regarding specific problem behaviors (two sessions). Main outcome measures: Caregivers and patients with dementia were assessed at baseline and after six months. For caregivers, the measures included strain (Zarit Burden Interview), psychological distress (SRQ-20), and quality of life (WHOQOL-BREF). Dementia patients completed scales assessing behavioral and psychological symptoms (NPI-Q) and quality of life (DEMQOL). RESULTS: Caregivers in the intervention group reported significantly decreased strain measures six months after the intervention compared to controls. No group differences were found in respect to the caregivers' psychological distress and to quality of life in both caregivers and patients. CONCLUSION: The 10/66 intervention seems to be as effective as similar interventions used in more developed countries.

OBJETIVO: Demência é um problema crescente nos países em desenvolvimento. Existe uma necessidade urgente, devido à falta de serviços formais, de desenvolver intervenções que visem melhorar a vida das pessoas portadoras de demência e de suas famílias. Este estudo testa a efetividade do programa de intervenção para pessoas com demência e seus cuidadores desenvolvido pelo grupo 10/66, em Lima, Peru. MÉTODO: Desenho/participantes: ensaio clínico randomizado. Cinquenta e oito cuidadores de pessoas com demência foram randomizados para receber a intervenção imediatamente (n = 29) ou seis meses após sua inclusão no estudo. A intervenção é composta por três módulos: 1) avaliação (uma sessão); 2) educação básica sobre demência (duas sessões); e 3) treinamento para lidar com problemas comportamentais específicos (duas sessões). Principais medidas de desfecho: os cuidadores e as pessoas com demência foram avaliados no início do estudo e depois de seis meses. Em relação aos cuidadores, os desfechos foram: sobrecarga (Zarit Burden Interview), estresse psicológico (SRQ-20); e qualidade de vida (WHOQOL-BREF). Em relação às pessoas com demência, os desfechos foram: sintomas comportamentais e psicológicos (NPI-Q); e qualidade de vida (DEMQOL). RESULTADOS: Os cuidadores que receberam a intervenção relataram diminuição estatisticamente significante nas medidas de sobrecarga quando reavaliados depois de seis meses, em comparação aos cuidadores do grupo-controle. Não foram observadas diferenças entre os grupos em relação a estresse psicológico dos cuidadores e qualidade de vida dos pacientes e cuidadores. CONCLUSÃO: Esta intervenção parece ser tão, se não mais, efetiva quanto intervenções similares aplicadas em países desenvolvidos.

Leg length, skull circumference, and the prevalence of dementia in low and middle income countries: a 10/66 population-based cross sectional survey.

BACKGROUND: Adult leg length is influenced by nutrition in the first few years of life. Adult head circumference is an indicator of brain growth. There is a limited literature linking short legs and small skulls to an increased risk for cognitive impairment and dementia in late life. METHODS: One phase cross-sectional surveys were carried out of all residents aged over 65 years in 11 catchment areas in China, India, Cuba, Dominican Republic, Venezuela, Mexico and Peru (n = 14,960). The cross-culturally validated 10/66 dementia diagnosis, and a sociodemographic and risk factor questionnaire were administered to all participants, and anthropometric measures taken. Poisson regression was used to calculate prevalence ratios for the effect of leg length and skull circumference upon 10/66 dementia, controlling for age, gender, education and family history of dementia. RESULTS: The pooled meta-analyzed fixed effect for leg length (highest vs. lowest quarter) was 0.82 (95% CI, 0.68-0.98) and for skull circumference 0.75 (95% CI, 0.63-0.89). While point estimates varied between sites, the proportion of the variability attributable to heterogeneity between studies as opposed to sampling error (I2) was 0% for leg length and 22% for skull circumference. The effects were independent and not mediated by family history of dementia. The effect of skull circumference was not modified by educational level or gender, and the effect of leg length was not modified by gender. CONCLUSIONS: Since leg length and skull circumference are said to remain stable throughout adulthood into old age, reverse causality is an unlikely explanation for the findings. Early life nutritional programming, as well as neurodevelopment may protect against neurodegeneration.

Helping carers to care: the 10/66 dementia research group's randomized control trial of a caregiver intervention in Peru.

OBJECTIVE: There is a need, in the absence of formal services, to design interventions aimed at improving the lives of people with dementia and their families. This study tested the effectiveness of the 10/66 caregiver intervention among people with dementia and their caregivers in Lima, Peru. DESIGN/PARTICIPANTS: a randomized controlled trial was performed involving 58 caregivers of people with dementia that received the intervention in the beginning of the trial (n = 29) or six months later (n = 29). The intervention consisted of three modules: 1) assessment (one session); 2) basic education about dementia (two sessions); and 3) training regarding specific problem behaviors (two sessions). MAIN OUTCOME MEASURES: Caregivers and patients with dementia were assessed at baseline and after six months. For caregivers, the measures included strain (Zarit Burden Interview), psychological distress (SRQ-20), and quality of life (WHOQOL-BREF). Dementia patients completed scales assessing behavioral and psychological symptoms (NPI-Q) and quality of life (DEMQOL). RESULTS: Caregivers in the intervention group reported significantly decreased strain measures six months after the intervention compared to controls. No group differences were found in respect to the caregivers' psychological distress and to quality of life in both caregivers and patients. CONCLUSION: The 10/66 intervention seems to be as effective as similar interventions used in more developed countries.

Measuring disability across cultures--the psychometric properties of the WHODAS II in older people from seven low- and middle-income countries. The 10/66 Dementia Research Group population-based survey.

We evaluated the psychometric properties of the 12-item interviewer-administered screener version of the World Health Organization Disability Assessment Schedule-version II (WHODAS II) among older people living in seven low- and middle-income countries. Principal component analysis (PCA), confirmatory factor analysis (CFA) and Mokken analyses were carried out to test for unidimensionality, hierarchical structure, and measurement invariance across 10/66 Dementia Research Group sites. PCA generated a one-factor solution in most sites. In CFA, the two-factor solution generated in Dominican Republic fitted better for all sites other than rural China. The two factors were not easily interpretable, and may have been an artefact of differing item difficulties. Strong internal consistency and high factor loadings for the one-factor solution supported unidimensionality. Furthermore, the WHODAS II was found to be a 'strong' Mokken scale. Measurement invariance was supported by the similarity of factor loadings across sites, and by the high between-site correlations in item difficulties. The Mokken results strongly support that the WHODAS II 12-item screener is a unidimensional and hierarchical scale confirming to item response theory (IRT) principles, at least at the monotone homogeneity model level. More work is needed to assess the generalizability of our findings to different populations.

Late-life depression in Peru, Mexico and Venezuela: the 10/66 population-based study.

BACKGROUND: The proportion of the global population aged 60 and over is increasing, more so in Latin America than any other region. Depression is common among elderly people and an important cause of disability worldwide. AIMS: To estimate the prevalence and correlates of late-life depression, associated disability and access to treatment in five locations in Latin America. METHOD: A one-phase cross-sectional survey of 5886 people aged 65 and over from urban and rural locations in Peru and Mexico and an urban site in Venezuela. Depression was identified according to DSM-IV and ICD-10 criteria, Geriatric Mental State-Automated Geriatric Examination for Computer Assisted Taxonomy (GMS-AGECAT) algorithm and EURO-D cut-off point. Poisson regression was used to estimate the independent associations of sociodemographic characteristics, economic circumstances and health status with ICD-10 depression. RESULTS: For DSM-IV major depression overall prevalence varied between 1.3% and 2.8% by site, for ICD-10 depressive episode between 4.5% and 5.1%, for GMS-AGECAT depression between 30.0% and 35.9% and for EURO-D depression between 26.1% and 31.2%; therefore, there was a considerable prevalence of clinically significant depression beyond that identified by ICD-10 and DSM-IV diagnostic criteria. Most older people with depression had never received treatment. Limiting physical impairments and a past history of depression were the two most consistent correlates of the ICD-10 depressive episode. CONCLUSIONS: The treatment gap poses a significant challenge for Latin American health systems, with their relatively weak primary care services and reliance on private specialists; local treatment trials could establish the cost-effectiveness of mental health investment in the government sector.

Contribution of chronic diseases to disability in elderly people in countries with low and middle incomes: a 10/66 Dementia Research Group population-based survey.

BACKGROUND: Disability in elderly people in countries with low and middle incomes is little studied; according to Global Burden of Disease estimates, visual impairment is the leading contributor to years lived with disability in this population. We aimed to assess the contribution of physical, mental, and cognitive chronic diseases to disability, and the extent to which sociodemographic and health characteristics account for geographical variation in disability. METHODS: We undertook cross-sectional surveys of residents aged older than 65 years (n=15 022) in 11 sites in seven countries with low and middle incomes (China, India, Cuba, Dominican Republic, Venezuela, Mexico, and Peru). Disability was assessed with the 12-item WHO disability assessment schedule 2.0. Dementia, depression, hypertension, and chronic obstructive pulmonary disease were ascertained by clinical assessment; diabetes, stroke, and heart disease by self-reported diagnosis; and sensory, gastrointestinal, skin, limb, and arthritic disorders by self-reported impairment. Independent contributions to disability scores were assessed by zero-inflated negative binomial regression and Poisson regression to generate population-attributable prevalence fractions (PAPF). FINDINGS: In regions other than rural India and Venezuela, dementia made the largest contribution to disability (median PAPF 25.1% [IQR 19.2-43.6]). Other substantial contributors were stroke (11.4% [1.8-21.4]), limb impairment (10.5% [5.7-33.8]), arthritis (9.9% [3.2-34.8]), depression (8.3% [0.5-23.0]), eyesight problems (6.8% [1.7-17.6]), and gastrointestinal impairments (6.5% [0.3-23.1]). Associations with chronic diseases accounted for around two-thirds of prevalent disability. When zero inflation was taken into account, between-site differences in disability scores were largely attributable to compositional differences in health and sociodemographic characteristics. INTERPRETATION: On the basis of empirical research, dementia, not blindness, is overwhelmingly the most important independent contributor to disability for elderly people in countries with low and middle incomes. Chronic diseases of the brain and mind deserve increased prioritisation. Besides disability, they lead to dependency and present stressful, complex, long-term challenges to carers. Societal costs are enormous. FUNDING: Wellcome Trust; WHO; US Alzheimer's Association; Fondo Nacional de Ciencia Y Tecnologia, Consejo de Desarrollo Cientifico Y Humanistico, Universidad Central de Venezuela.

Population normative data for the 10/66 Dementia Research Group cognitive test battery from Latin America, India and China: a cross-sectional survey.

BACKGROUND: 1) To report site-specific normative values by age, sex and educational level for four components of the 10/66 Dementia Research Group cognitive test battery; 2) to estimate the main and interactive effects of age, sex, and educational level by site; and 3) to investigate the effect of site by region and by rural or urban location. METHODS: Population-based cross-sectional one phase catchment area surveys were conducted in Cuba, Dominican Republic, Venezuela, Peru, Mexico, China and India. The protocol included the administration of the Community Screening Instrument for Dementia (CSI 'D', generating the COGSCORE measure of global function), and the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) verbal fluency (VF), word list memory (WLM, immediate recall) and recall (WLR, delayed recall) tests. Only those free of dementia were included in the analysis. RESULTS: Older people, and those with less education performed worse on all four tests. The effect of sex was much smaller and less consistent. There was a considerable effect of site after accounting for compositional differences in age, education and sex. Much of this was accounted for by the effect of region with Chinese participants performing better, and Indian participants worse, than those from Latin America. The effect of region was more prominent for VF and WLM than for COGSCORE and WLR. CONCLUSION: Cognitive assessment is a basic element for dementia diagnosis. Age- and education-specific norms are required for this purpose, while the effect of gender can probably be ignored. The basis of cultural effects is poorly understood, but our findings serve to emphasise that normative data may not be safely generalised from one population to another with quite different characteristics. The minimal effects of region on COGSCORE and WLR are reassuring with respect to the cross-cultural validity of the 10/66 dementia diagnosis, which uses only these elements of the 10/66 battery.

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

BACKGROUND: Studies have suggested that the prevalence of dementia is lower in developing than in developed regions. We investigated the prevalence and severity of dementia in sites in low-income and middle-income countries according to two definitions of dementia diagnosis. METHODS: We undertook one-phase cross-sectional surveys of all residents aged 65 years and older (n=14 960) in 11 sites in seven low-income and middle-income countries (China, India, Cuba, Dominican Republic, Venezuela, Mexico, and Peru). Dementia diagnosis was made according to the culturally and educationally sensitive 10/66 dementia diagnostic algorithm, which had been prevalidated in 25 Latin American, Asian, and African centres; and by computerised application of the dementia criterion from the Diagnostic and Statistical Manual of Mental Disorders (DSM IV). We also compared prevalence of DSM-IV dementia in each of the study sites with that from estimates in European studies. FINDINGS: The prevalence of DSM-IV dementia varied widely, from 0.3% (95% CI 0.1-0.5) in rural India to 6.3% (5.0-7.7) in Cuba. After standardisation for age and sex, DSM-IV prevalence in urban Latin American sites was four-fifths of that in Europe (standardised morbidity ratio 80 [95% CI 70-91]), but in China the prevalence was only half (56 [32-91] in rural China), and in India and rural Latin America a quarter or less of the European prevalence (18 [5-34] in rural India). 10/66 dementia prevalence was higher than that of DSM-IV dementia, and more consistent across sites, varying between 5.6% (95% CI 4.2-7.0) in rural China and 11.7% (10.3-13.1) in the Dominican Republic. The validity of the 847 of 1345 cases of 10/66 dementia not confirmed by DSM-IV was supported by high levels of associated disability (mean WHO Disability Assessment Schedule II score 33.7 [SD 28.6]). INTERPRETATION: As compared with the 10/66 dementia algorithm, the DSM-IV dementia criterion might underestimate dementia prevalence, especially in regions with low awareness of this emerging public-health problem.