The magnitude of dementia occurrence in the world.

In this study, the worldwide occurrence of dementia in 2000 and during the period 1950-2050 was estimated. The calculations were based on worldwide demographics of the elderly and age-specific prevalence and incidence values of dementia, estimated from a meta-analysis. In a sensitivity analysis, different prevalence sources were used. The worldwide number of persons with dementia in 2000 was estimated at about 25 million persons. Almost half of the demented persons (46%) lived in Asia, 30% in Europe, and 12% in North America. Fifty-two percent lived in less developed regions. About 6.1% of the population 65 years of age and older suffered from dementia (about 0.5% of the worldwide population) and 59% were female. The number of new cases of dementia in 2000 was estimated to be 4.6 million. The forecast indicated a considerable increase in the number of demented elderly from 25 million in the year 2000 to 63 million in 2030 (41 million in less developed regions) and to 114 million in 2050 (84 million in less developed regions). In conclusion, the majority of demented elders live in less developed regions, and this proportion will increase considerably in the future.