Proportion of older people in the community as a predictor of increasing stroke incidence.
OBJECTIVE
To compare stroke incidence rates among comparable registries and to make correlations with aging of the resident populations.


METHODS
This correlation study included all comparable stroke registries maintained in industrialized countries (Italy, France, United Kingdom, Denmark, Norway, United States, and Australia). Eleven community-based stroke registries with similar high proportions of radiologically confirmed diagnoses based on standard definitions were identified. Incidence rates of first-ever stroke from the prospective L'Aquila registry and from the other registries were compared after age and sex standardization to the 1996 European population. The rates were then correlated with the proportion of individuals aged 65 and over in the corresponding resident populations by means of the Poisson regression analysis.


RESULTS
In the L'Aquila registry, the crude annual incidence of first-ever stroke was 281/100,000 (95% confidence interval 271-293) based on 2,515 patients included during a 3-year period. The rate standardized to the European population was 249/100,000. Standardized incidence ratios indicated a significant excess of first-ever strokes in the L'Aquila registry up to 51% with respect to most of the compared studies. A significant correlation was also found between crude (p < 0.0001) and standardized (p = 0.0012) stroke incidence rates and proportions of individuals aged 65 and over in the different populations.


CONCLUSIONS
The L'Aquila experience suggests that any further aging of a population will increase the stroke occurrence for both the reasons of a direct and predictable effect of the growing proportion of elderly individuals within that population and a disproportionately increased stroke risk in the older age groups.
Marini
C
C
Institute of Neurology, Department of Internal Medicine and Public Health, University of L'Aquila, L'Aquila-Coppito, Italy. marini@aquila.infn.it
Triggiani
L
L
Cimini
N
N
Ciancarelli
I
I
De Santis
F
F
Russo
T
T
Baldassarre
M
M
di Orio
F
F
Carolei
A
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003153:Community Health Services; D005260:Female; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010343:Patient Admission / Q000706:statistics & numerical data; D011446:Prospective Studies; D012042:Registries; D020521:Stroke / Q000453:epidemiology*; D000071939:Stroke Rehabilitation