Well-designed epidemiological research is relatively lacking in low and middle income countries where two-thirds of the world's estimated 24 million people with dementia live. The 10/66 Dementia Research Group has sought since 1998 to redress this imbalance. Pilot studies to develop and validate dementia diagnostic measures and study care arrangements in 26 centers worldwide were followed by one phase cross-sectional catchment area surveys in eight Latin American countries, China, India, Nigeria and South Africa. The protocol includes assessment of sociodemographics, disability, care arrangements, physical and mental health, and dementia diagnosis with (more restrictive) DSM-IV and (less restrictive) 10/66 dementia criteria. An incidence phase is underway in eight countries. 10/66 dementia prevalence is generally double that of DSM-IV dementia. DSM-IV dementia is particularly rare in India, attributable to the small proportion of family informants confirming cognitive decline and social impairment. Carer psychological and economic strain is as high as in the developed world, despite traditional family care arrangements. A significant minority of people with dementia are vulnerable due to lack of family support and economic resources. Earlier studies probably underestimated dementia prevalence in regions with very low awareness of this emerging public health problem. More research is needed to delineate the impact of dementia relative to other chronic diseases, and secular trends in countries experiencing rapid demographic ageing and health transition. Packages of care are also a priority - healthcare services and governments have not responded to families' complex needs for support in their long-term care role.
Keywords: Dementia research; dementia care; dementia diagnosis; developing countries; epidemiology of dementia.