Démences en Afrique Subsaharienne : outils, prévalence et facteurs de risque

Given the ageing population worldwide and the consequent epidemiological transitions, dementia is now a major public health concern in developing countries. The burden of dementia implies human, social, and economical consequences. First estimates of dementia prevalence in developing countries reported low rates (<5%) contrasting with observations made in developed countries, ranging from 5 to 20%. Few studies have been carried out in Africa whereas african elderly population will dramatically increase by 2025.During this PhD thesis, we studied the different tools allowing to screen dementia in low income countries, where culture differences and illiteracy are important. The determination of age in epidemiological studies focused on neurodegenerative disorders like dementia is of great importance, so a method to estimate the age with historical landmarks was validated.Three population-based studies were carried out in french speaking african countries: in Djidja (Benin), in Bangui (Central African Republic) and in Brazzaville (Congo), in order to estimate prevalence of dementia in elderly over 65 years and to study risk factors for this affection. By a door-to-door approach, these studies allowed to screen about 500 subjects in each study site with the Community Screening Interview for Dementia (CSI-D) and the Five Words Test. The prevalence of dementia was low in the rural area of Benin (2.6%), whereas it was higher in Central African cities (8.1% in Bangui and 6.7% in Brazzaville). Age and current depressive symptoms were the two factors most significantly associated with dementia in these populations. Surprisingly, the absence of schooling was never associated with dementia. The association between dementia and Lower-Extremities Peripheral Artery Disease (PAD) has particularly been explored in Central Africa, using the ankle-brachial index as a marker of PAD and general atherosclerosis. While the prevalence of PAD was high in elder population (15.0% in Bangui and 32.4% in Brazzaville), a low ABI (<0.9) was often associated with dementia, even after adjustment on CVD and dementia risk factors.Researches on dementia in low-income countries have increased during the last years. Prevalence of dementia seems to vary between different regions of Africa, and between urban and rural areas. Beyond the usual risk factors for dementia, our studies highlighted the role of psychosocial risk factors in low income countries.Suite au vieillissement de la population mondiale et compte-tenu de la transition épidémiologique en cours, les démences deviennent un problème majeur de santé publique dans les pays en développement. En effet, les conséquences humaines, sociales et économiques liées aux démences et à la maladie d’Alzheimer sont lourdes. Les premières estimations de la prévalence des démences dans les pays en développement étaient faibles, souvent inférieures à 5%, contrastant avec les observations faites dans les pays développés où la prévalence variait entre 5 et 20%. Peu de recherches sur les démences ont été menées en Afrique alors qu’une augmentation de 93% de la population de personnes âgées vivant en Afrique Subsaharienne est prévue par l’OMS entre 2000 et 2020.Au cours de cette thèse, nous avons étudié les outils permettant de dépister les démences dans les pays à faibles revenus en zone tropicale, où les différences culturelles et l’illettrisme sont importants. L’âge des sujets devant être déterminé avec précision lors d’enquêtes épidémiologiques sur les démences, une méthode d’estimation de l’âge via des repères historiques a été validée.Trois études épidémiologiques en population générale ont été conduites en Afrique francophone : à Djidja (Bénin), à Bangui (République Centrafricaine) et à Brazzaville (Congo), afin d’estimer la prévalence des démences chez les sujets de plus de 65 ans et d’étudier les facteurs de risque de ces affections. Ces études, par la méthode de porte-à-porte, ont permis de dépister environ 500 sujets dans chaque zone avec le Community Screening Interview for Dementia et le Test des 5 mots. La prévalence des démences était faible en zone rurale béninoise (2,6%), alors qu’elle était plus élevée dans les villes d’Afrique Centrale (8,1% à Bangui et 6,7% à Brazzaville). L’âge et les symptômes dépressifs au moment de l’étude étaient les deux facteurs les plus souvent significativement associés aux démences dans ces populations, tandis que la non scolarisation n’était jamais associée aux démences.L’association des démences avec l’Artériopathie Oblitérante des Membres Inférieurs (AOMI) a été plus particulièrement explorée en Afrique Centrale. Alors que la prévalence de l’AOMI était élevée dans la population âgée (15,0% à Bangui et 32,4% à Brazzaville), un Index de Pression Systolique faible (<0,9) était associé à la présence de démences, même après ajustement sur les facteurs de risque de démences et de maladies cardiovasculaires.Les recherches sur les démences dans les pays à faibles ou moyens revenus ont progressé durant ces dernières années. La prévalence des démences semble varier d’une région d’Afrique à l’autre, selon le milieu urbain ou rural. En plus des facteurs de risque usuels, certains facteurs de risque psychosociaux semblent jouer un rôle dans la survenue de démence

World Alzheimer report 2016: improving healthcare for people living with dementia: coverage, quality and costs now and in the future

The World Alzheimer Report 2016, Improving healthcare for people living with dementia: Coverage, quality and costs now and in the future, reviews research evidence on the elements of healthcare for people with dementia, and, using economic modelling, suggests how it should be improved and made more efficient. The report argues that current dementia healthcare services are over-specialised, and that a rebalancing is required with a more prominent role for primary and community care. This would increase capacity, limit the increased costs associated with scaling up coverage of care, and, coupled with the introduction of care pathways and case management, improve the coordination and integration of care. Modelling of the costs of care pathways was carried out in Canada, China, Indonesia, Mexico, South Africa, South Korea and Switzerland, to estimate the costs of dementia healthcare under different assumptions regarding delivery systems. The report was researched and authored by Prof Martin Prince, Ms Adelina Comas-Herrera, Prof Martin Knapp, Dr Maëlenn Guerchet and Ms Maria Karagiannidou from The Global Observatory for Ageing and Dementia Care, King’s College London and the Personal Social Services Research Unit (PSSRU), London School of Economics and Political Science

0579: Particularities of the epidemiology of hypertension in the elderly in Central Africa: the EPIDEMCA study

BackgroundThe epidemiology of hypertension in the elderly is rarely reported in Africa and little is known about its specificities.ObjectiveTo study the prevalence of hypertension and associated factors in older people in Central Africa.MethodsIndividuals aged 65 years old and over living in two urban and two rural areas of the Republic of Congo (ROC) and the Central African Republic (CAR) were invited to participate into a comprehensive cross-sectional study assessing cognitive impairments and cardiovascular diseases. Demographic, clinical and biological data were collected. Hypertension was defined in case of self-reported on-going treatment and/or when averaged systolic blood pressure at rest was≥140mmHg and/or diastolic blood pressure was≥90mmHg.ResultsAmong 1990 participants (mean age=73 years; 62% females), the overall prevalence of hypertension was 61.1% (95% CI: 58.9-63.2), higher in ROC than in CAR (68.0% vs 53.7%, respectively; p<0.001) and higher in urban than in rural areas (64.7% vs 57.4%, respectively; p=0.001). Among hypertensive participants, 53.3% were unaware of their condition and only 17.3% received anti-hypertensive drug therapy. In multivariate analysis, increasing age and BMI, living in the ROC, the main lifetime occupation, presence of depressive symptoms and the number of meals per day remained significantly associated with an increased likelihood of hypertension. In contrast, smoking status, physical activity and an increasing number of stressful lifetime events were associated with a reduced likelihood for prevalent hypertension.ConclusionHypertension is highly prevalent in elderly people of Central Africa, and presents some particularities in relation to specific conditions in this region

Prevalence of dementia in mainland China, Hong Kong and Taiwan: an updated systematic review and meta-analysis.

BACKGROUND: There are several existing systematic reviews of prevalence of dementia for mainland China, Hong Kong and Taiwan, but several studies have been newly reported. The aim of this study is to update prevalence data in this region and test for variation across geographical areas and time periods using the new dataset. METHODS: Twenty prevalence studies identified from World Alzheimer Report 2015 (January 2011-March 2015) and an updated search (March 2015-February 2017) were added to the original dataset (N = 76). Meta-regression was used to investigate geographical variation and time trends, taking methodological factors and characteristics of study population into account, and to estimate prevalence and number of people with dementia by geographical area. RESULTS: Compared with northern China, the prevalence of dementia was lower in the central China [-1.0; 95% confidence interval (CI):-2.2, 0.3], south China (-1.7; 95% CI: -3.1, -0.3), Hong Kong and Taiwan (-3.0; 95% CI: -5.0, -1.0) but appeared to be higher in western China (2.8; 95% CI: 0.1, 5.5) after adjusting for methodological variation. The increasing trend from pre-1990 to post-2010 periods was considerably attenuated when taking into account methodological factors and geographical areas. The updated estimated number of people with dementia in all these areas is 9.5 million (5.3%; 95% CI: 4.3, 6.3) in the population aged 60 or above. CONCLUSIONS: Geographical variation in dementia prevalence is confirmed in this update, whereas evidence on increasing trends is still insufficient. Differing societal development across areas provides an opportunity to investigate risk factors at the population level operating across diverse life course experiences. Such research could advance global primary prevention of dementia

The worldwide costs of dementia in 2019

Introduction: Dementia is a leading cause of death and disability globally. Estimating total societal costs demonstrates the wide impact of dementia and its main direct and indirect economic components. Methods: We constructed a global cost model for dementia, presenting costs as cumulated global and regional costs. Results: In 2019, the annual global societal costs of dementia were estimated at US $1313.4 billion for 55.2 million people with dementia, corresponding to US$23,796 per person with dementia. Of the total, US $213.2 billion (16$448.7 billion (34%) direct social sector costs (including long-term care), and US $651.4 billion (50$1313.4 in 2019. Sixty-one percent of people with dementia live in low-and middle-income countries, whereas 74% of the costs occur in high-income countries. The impact of informal care accounts for about 50% of the global costs. The development of a long-term care infrastructure is a great challenge for low-and middle-income countries. There is a great need for more cost studies, particularly in low- and middle-income countries. Discussions of a framework for global cost comparisons are needed

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

"When someone becomes old then every part of the body too becomes old": Experiences of living with dementia in Kintampo, rural Ghana.

Studies have suggested that in African countries, symptoms of cognitive decline are commonly seen as part of "normal ageing" or attributed to supernatural causes. The impact of folk beliefs about causality upon help-seeking is unclear. Likewise, there is a lack of evidence relating to how families cope with living with an older resident with dementia. Our study's aim was to explore the sociocultural beliefs, understandings, perceptions and behaviours relating to living with dementia in Kintampo, Ghana. We conducted in-depth interviews with a total of 28 people, using a series of case studies among 10 older people living with dementia and their families. Results revealed that symptoms of cognitive impairment were generally linked to inexorable bodily decline understood to be characteristic of "normal" ageing. Stigma was therefore perceived to be non-existent. Whilst managing the costs of care was often a challenge, care-giving was largely accepted as a filial duty, commonly shared among female residents of large compound households. Families experimented with biomedical and traditional medicine for chronic conditions they perceived to be treatable. Our findings suggest that whilst families offer a holistic approach to the needs of older people living with chronic conditions including dementia, health and social policies offer inadequate scaffolding to support this work. In the future, it will be important to develop policy frameworks that acknowledge the continued social and economic potential of older people and strengthen the existing approach of families, optimising the management of non-communicable diseases within primary care

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

Social connections and risk of incident mild cognitive impairment, dementia, and mortality in 13 longitudinal cohort studies of ageing

INTRODUCTION: Previous meta-analyses have linked social connections and mild cognitive impairment, dementia, and mortality. However, these used aggregate data from North America and Europe and examined a limited number of social connection markers. METHODS: We used individual participant data (N = 39271, Mage  = 70.67 (40-102), 58.86% female, Meducation  = 8.43 years, Mfollow-up  = 3.22 years) from 13 longitudinal ageing studies. A two-stage meta-analysis of Cox regression models examined the association between social connection markers with our primary outcomes. RESULTS: We found associations between good social connections structure and quality and lower risk of incident mild cognitive impairment (MCI); between social structure and function and lower risk of incident dementia and mortality. Only in Asian cohorts, being married/in a relationship was associated with reduced risk of dementia, and having a confidante was associated with reduced risk of dementia and mortality. DISCUSSION: Different aspects of social connections - structure, function, and quality - are associated with benefits for healthy aging internationally. HIGHLIGHTS: Social connection structure (being married/in a relationship, weekly community group engagement, weekly family/friend interactions) and quality (never lonely) were associated with lower risk of incident MCI. Social connection structure (monthly/weekly friend/family interactions) and function (having a confidante) were associated with lower risk of incident dementia. Social connection structure (living with others, yearly/monthly/weekly community group engagement) and function (having a confidante) were associated with lower risk of mortality. Evidence from 13 longitudinal cohort studies of ageing indicates that social connections are important targets for reducing risk of incident MCI, incident dementia, and mortality. Only in Asian cohorts, being married/in a relationship was associated with reduced risk of dementia, and having a confidante was associated with reduced risk of dementia and mortality