Incidence rate and spatio-temporal clustering of type 1 diabetes in Santiago, Chile, from 1997 to 1998.
OBJECTIVE
To estimate the incidence rate of type 1 diabetes in the urban area of Santiago, Chile, from March 21, 1997 to March 20, 1998, and to assess the spatio-temporal clustering of cases during that period.


METHODS
All sixty-one incident cases were located temporally (day of diagnosis) and spatially (place of residence) in the area of study. Knox's method was used to assess spatio-temporal clustering of incident cases.


RESULTS
The overall incidence rate of type 1 diabetes was 4.11 cases per 100,000 children aged less than 15 years per year (95% confidence interval: 3.06 - 5.14). The incidence rate seems to have increased since the last estimate of the incidence calculated for the years 1986 - 1992 in the metropolitan region of Santiago. Different combinations of space-time intervals have been evaluated to assess spatio-temporal clustering. The smallest p-value was found for the combination of critical distances of 750 meters and 60 days (uncorrected p-value = 0.048).


CONCLUSIONS
Although these are preliminary results regarding space-time clustering in Santiago, exploratory analysis of the data method would suggest a possible aggregation of incident cases in space-time coordinates.
Santos
J
J
Instituto de Nutrición y Tecnologia de Alimentos, Universidad de Chile, Santiago, Chile.
Carrasco
E
E
Moore
A
A
Pérez-Bravo
F
F
Albala
C
C
D000293:Adolescent; D002648:Child; D002677:Chile / Q000453:epidemiology; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D012621:Seasons; D013029:Space-Time Clustering; D014505:Urban Population / Q000706:statistics & numerical data*