The Lancet 2008; 372:464-474 DOI:10.1016/S0140-6736(08)61002-8
Prevalence of dementia in Latin America, India, and China: a population-based cross-sectional survey
Prof Juan J Llibre Rodriguez MD a, Cleusa P Ferri PhD b, Daisy Acosta MD c, Mariella Guerra PhD d, Prof Yueqin Huang PhD e, Prof KS Jacob PhD f, Prof ES Krishnamoorthy PhD g, Aquiles Salas MD h, Ana Luisa Sosa MSc i, Isaac Acosta Lic i, Michael E Dewey PhD b, Ciro Gaona MD j, AT Jotheeswaran MSc g, Prof Shuran Li MD e, Diana Rodriguez PhD k, Guillermina Rodriguez Lic l, P Senthil Kumar MSW f, Adolfo Valhuerdi MD m and Prof Martin Prince MD b , for the 10/66 Dementia Research Group
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=14960) 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.
Prevalence of dementia in Latin America, India, and China: a population-based cross-sectional survey
Prof Juan J Llibre Rodriguez MD a, Cleusa P Ferri PhD b, Daisy Acosta MD c, Mariella Guerra PhD d, Prof Yueqin Huang PhD e, Prof KS Jacob PhD f, Prof ES Krishnamoorthy PhD g, Aquiles Salas MD h, Ana Luisa Sosa MSc i, Isaac Acosta Lic i, Michael E Dewey PhD b, Ciro Gaona MD j, AT Jotheeswaran MSc g, Prof Shuran Li MD e, Diana Rodriguez PhD k, Guillermina Rodriguez Lic l, P Senthil Kumar MSW f, Adolfo Valhuerdi MD m and Prof Martin Prince MD b , for the 10/66 Dementia Research Group
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=14960) 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.
