Levels of dementia underestimated in developing countries

23 May 2012 - Conventional estimates of dementia incidence in middle-income countries have been too optimistic, suggests one of the largest studies of dementia incidence to date from ADI's 10/66 Dementia Research Group, published online in The Lancet today.

The findings suggest that dementia incidence in middle-income countries might be much the same as in higher-income countries. Moreover, this is the first study to demonstrate that in less developed countries, as in developed nations, education offers substantial protection against dementia. New estimates, generated using a cross-cultural approach to diagnosing dementia that is sensitive to more mild to moderate cases (the 10/66 Dementia Diagnosis), indicate that incidence is 1.5-2.5 times higher than that calculated using standard DSM-IV criteria.

Professor Martin Prince of the Institute of Psychiatry at King's College London, who led the research, said: ‘Our studies provide supportive evidence for the cognitive reserve hypothesis — that better brain development can mitigate the effects of neurodegeneration in later-life. Our findings suggest that early life influences, education and learning to read and write, may be particularly important for reducing the risk of dementia in late life. We need to understand more about cognitive reserve, how to measure it, and how it is stimulated across cultures. The high incidence of dementia in less developed countries reminds us that we are facing a global epidemic, and there needs to be more focus on prevention.’