Epidemiology of alzheimer's disease

ABSTRACT

Epidemiological studies on Alzheimer's disease are difficult because the condition has an insidious onest and dose not have any specific biological or radiological marker. Available data suggest that Alzheimer's disease prevalence increases with age from less than 1% at age 60 to more than 35% at age 95. Its yearly incidence is around 1% at age 70 and 4% above 80. The total duration of the disease is about 8 years but familial cases and those with early onset are usually shorter. Apart from age, the main risk factors for the development of Alzheimer's disease are family history and genetic disorders such as trisomy 21 and abnormal genes on chromosomes 1, 14, 19 and 21. The allele E4 of apolipoprotein E [A[p]oE] gene on chromosome 19 is of particular interest in non-familial Alzheirmer's disease. On the other hand, some factors such as estrange replacement therapy, non-inflammatory drugs, cigarette smoking and the allele E2 of A[p]oE gene seem to protect against Alzheimer's disease