[Dementia in nonagenarians. Systematic review of population-based studies with Spanish data].
BACKGROUND
Ageing is associated with the quasi exponential getting up of dementia prevalence and incidence until 85 years, but the data in the oldest-old are controversial. AIM. Systematic review of population based studies that analyze prevalence and incidence of dementia in the oldest-old, specifically in nonagenarians.


METHODS
Systematic review in Medline database of population based surveys describing prevalence or incidence in older than 90, published from 1989. 459 papers were identified, but of the 170 population-based detailed reviewed, 41 studies accomplished the inclusion criteria (Pamplona, Gerona and NEDICES Study are included).


RESULTS
The dementia prevalence described in nonagenarians has a range of 25-54%. The dementia incidence in older than 90 has a range of 47-174 cases per 1,000 people/year, being greater in females. In the oldest-old a variable prevalence and incidence of dementia was described in the selected studies. Some authors consider that exist an exponential increase in the dementia prevalence and another ones indicate a slowing of growth in nonagenarians.


CONCLUSIONS
This review is concordant with a persistent not exponential increase in prevalence and incidence of dementia in nonagenarians.
Carrillo-Alcalá
M E
ME
Servicio de Geriatría, Hospital Guadarrama, Guadarrama, Madrid. m.c.alca@teleline.es
Bermejo-Pareja
F
F
D000368:Aged; D000369:Aged, 80 and over; D003704:Dementia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D016239:MEDLINE; D013030:Spain / Q000453:epidemiology
Demencia en nonagenarios. Revisión sistemáticade estudios poblacionales con datos de España.