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

Abstract

SummaryBackgroundStudies 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.MethodsWe 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.FindingsThe 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]).InterpretationAs 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.FundingWellcome Trust (UK); WHO; the US Alzheimer's Association; and Fondo Nacional De Ciencia Y Tecnologia, Consejo De Desarrollo Cientifico Y Humanistico, and Universidad Central De Venezuela (Venezuela).

Nursing Students' Intentions to Work in Dementia Care: Influence of Age, Ageism, and Perceived Barriers

“…Subsequent studies from francophone countries in western and central Africa (38)(39)(40), and one further study from northern Nigeria (41) suggest a more variable prevalence, higher in urban than in rural sites, and higher in central compared with western Africa. The Nigerian study recorded a low prevalence that is consistent with findings from the earlier USA / Nigeria study (2.4% for those aged 65 and over, age-stan- suggested that the true prevalence at baseline was likely to be much closer to the 7.5% recorded for 10 / 66 dementia than the 0.9% prevalence according to DSM-IV criteria (20).…”

“…In the 10 / 66 Dementia Research Group studies (Box 2.1), the group's 10 / 66 dementia diagnosis -developed, calibrated and validated in a 26-site pilot study (42) -was both more prevalent than that according to DSM-IV criteria, and more consistent between sites. The prevalence of DSM-IV dementia was particularly low in rural and less developed sites (20). It may be that milder dementia is under-detected in LMIC because of low awareness, high levels of support routinely provided to older people, and reluctance to report failings to outsiders, which could all contribute to difficulties in establishing the DSM-IV criterion of social and occupational impairment (18,20).…”

Very low levels of education and cognitive reserve

“…Such intervention would have a strong health policy implication because two-thirds of people with dementia live in developing countries where the prevalence of illiteracy is still high. 13,14 Additional limitations are acknowledged. The clinical information was obtained through an informant and thus our measurement of cognitive ability may have been less accurate than a direct assessment.…”

“…13 Most of these individuals live in developing countries, which already are home to approximately 60% of the subjects who have dementia. 14 In this study, we examined the cognitive reserve theory in a population with a high prevalence of extremely low levels of formal education. Furthermore, we tested the hypothesis that even a few years of formal education would reduce the deleterious effects of neuropathologic indices (i.e., AD pathologic changes, lacunar infarctions, small-vessel disease, and Lewy body pathology) on the likelihood of having cognitive impairment.…”

The Mthfr 677t Allele May Influence the Severity and Biochemical Risk Factors of Alzheimer'Sdisease in an Egyptian Population

“…Statistics is much more ambiguous in the developing world, where few studies have examined the prevalence of dementia and where estimates vary widely. Evidence on the prevalence of AD is abundant in Europe and North America, patchy in South and 440 Disease Markers Southeast Asia, and very limited in Africa, the Middle East, Russia, Eastern Europe, and Latin America [3].…”