The prevalence of dementia in this rural Tanzanian population is similar to that reported in high-income countries. Dementia is likely to become a significant health burden in this population as demographic transition continues. Further research on risk factors for dementia in sub-Saharan Africa is needed to inform policy makers and plan local health services.

BackgroundWe have previously reported the prevalence of dementia in older adults living in the rural Hai district of Tanzania according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria. The aim of this study was to compare prevalence rates using the DSM-IV criteria with those obtained using the 10/66 diagnostic criteria, which is specifically designed for use in low- and middle-income countries.MethodsIn phase I, 1,198 people aged 70 and older were screened for dementia. A stratified sample of 296 was then clinically assessed for dementia according to the DSM-IV criteria. In addition, data were collected according to the protocol of the 10/66 Dementia Research Group, which allowed a separate diagnosis of dementia according to these criteria to be established.ResultsThe age-standardised prevalence of clinical DSM-IV dementia was 6.4% (95% confidence interval [CI] 4.9–7.9%) and of ‘10/66 dementia’ was 21.6% (95% CI 17.5–25.7%). Education was a significant predictor of ‘10/66 dementia’, but not of DSM-IV dementia.ConclusionsThere are large discrepancies in dementia prevalence rates depending on which diagnostic system is used. In rural sub-Saharan Africa, it is not clear whether the association between education and dementia using the 10/66 criteria is a genuine effect or the result of an educational bias within the diagnostic instrument. Despite its possible flaws, the DSM-IV criteria represent an international standard for dementia diagnosis. The 10/66 diagnostic criteria may be more appropriate when identification of early and mild cognitive impairment is required.

The 6-item brief dementia screening instrument has acceptable properties and will be further tested and validated during future fieldwork. Although developed for use in sub-Saharan Africa, it may be of use in other world regions where the use of other cognitive screening instruments may result in bias due to low levels of formal education.

The frequency of BPS in dementia in this rural Tanzanian population is high and comparable to that reported in prevalence studies from high income countries. Symptoms were also common, although to a lesser degree, amongst cognitively intact subjects. BPS are likely to have a significant impact on quality of life for elderly persons and their carers in low-income settings. Low-cost interventions, such as community-based therapy and education, are needed.

ABSTRACT. The majority of people with dementia worldwide live in developing countries. Studies from the developed world have reported an association between lower educational attainment and dementia, but there are few data from the developing world where literacy and educational levels are frequently much lower. In this study we assessed the association between education and dementia prevalence in a rural Tanzanian setting. Methods: In phase I, 1198 individuals aged 70 and over were assessed using the Community Screening Instrument for Dementia (CSI-D). In phase Ii a stratified sample of those seen in phase I were fully assessed and a clinical diagnosis based on DSM-IV criteria was made where appropriate. Information regarding literacy, highest attained educational level and occupation were also collected. Results: The median subject cognitive score on the CSI-D was 25.7 (IQR 22.7 to 28.0) for females and 27.7 (IQR 25.7 to 29.4) for males. This difference was significant (U=117770.0, z= -9.880, p<0.001). In both males and females a lower CSI-D subject cognitive score was significantly associated with having had no formal education (U=34866.5, z= -6.688, p<0.001, for females; U=20757.0, z= -6.278, p<0.001, for males). After adjusting for the effect of age, having no formal education was significantly associated with greater odds of having 'probable dementia' by CSI-D, as was illiteracy. Amongst those interviewed in phase II, there was no significant difference in literacy or education between those with diagnosed DSM-IV dementia and those without. Conclusion: In this rural Tanzanian population, we found a significant association between low levels of education and dementia by CSI-D. This relationship was not significant in cases meeting DSM-IV criteria for dementia. Key words: dementia, education, schooling, Tanzania, Africa.ASSOCIAÇÃO ENTRE NÍVEL EDUCACIONAL E DEMÊNCIA NA ZONA RURAL DA TANZÂNIA RESUMO. A maioria das pessoas com demência no mundo vivem em países em desenvolvimento. Estudos realizados em países desenvolvidos têm relatado uma associação entre baixa escolaridade e demência, onde os níveis de alfabetização e educação são frequentemente muito mais baixos. Neste estudo avaliou-se a associação entre a educação e a prevalência de demência em um cenário rural da Tanzânia. Métodos: Na fase I, 1.198 indivíduos com 70 anos ou mais foram avaliados utilizando o Instrumento de Rastreamento Comunitário para Demência (CSI-D). Na Fase II uma amostra estratificada dos pacientes avaliados na fase I foram totalmente avaliados e um diagnóstico clínico baseado em critérios do DSM-IV foi feito quando necessário. Resultados: A mediana do escore cognitivo no CSI-D foi de 25,7 (IQR 22,7-28,0) para o sexo feminino e 27,7 (IQR 25,7-29,4) para o sexo masculino. Esta diferença foi significativa (U=117770,0, z= -9,880, p <0,001). Em ambos os sexos, masculino e feminino a pontuação cognitiva menor no CSI-D foi significativamente associada com ausência de educação formal (U=34866,5, z= -6,688, p <0,001, para as mulheres; U=20757,...