ABSTRACT
Prevalence of dementia The prevalence of dementia is difficult to establish. In a Canadian study, the rates varied from 3.1% to 29% of the population studied, depending of which of six systems of diagnosis were used.1 Pooled data from many studies give the prevalence as shown in Table 7.1. Table 7.1: Prevalence of dementia in the population in Canada
That is, about one in every five people over the age of 80 years suffers from dementia. Most studies show no sex difference in prevalence although some show a slightly higher rate of Alzheimer’s disease in women. Regional differ ences appear in many studies but because of the difficulties of precise classi fication they give a confusing picture. It is suggested that dementia may be less common in rural than in urban areas, and some types of dementia may be more common in some countries.
