title: Geographical variability of the incidence of Type 1 diabetes in subjects younger than 30 years in Catalonia, Spain.
abstract: OBJECTIVE
  We decided to assess the geographical variability of the incidence of Type 1 diabetes in Catalonia (Spain) in subjects younger than 30 years at onset during the period 1989-1998. The effect of sex, age at onset, periods of years, and population density was also analyzed.
  
  
  METHODS
  Data were obtained from the prospective Catalan Registry of Diabetes Mellitus. Generalized linear mixed models were used to determine the effects of the risk factors and to find out the geographical distribution. The best model was selected by the AKAIKE information criterion.
  
  
  RESULTS
  The crude incidence of type 1 diabetes in subjects younger than 30 years was 11.8/100,000/year (95% CI 11.4-12.3). The incidence was similar between males and females in the 0-14 age group. However, there was a male preponderance in young adults. The incidence did not vary annually and was not associated with population density. The incidence did not present a spatial pattern around Catalonia. There was an unstructured geographical variability.
  
  
  CONCLUSIONS
  Some regions of Catalonia displayed values of type I diabetes higher or lower than the expected incidence. Counties with extreme values of incidence were specific for each demographic group and in no case did these counties make up clusters, suggesting that there are explanatory factors with patterns of geographic distribution. The incidence of diabetes in young male adults in some counties was similar to that of European countries with a high incidence.
authors.affiliation: Departament de Salut Pública, Universitat de Barcelona, Barcelona, Spain. rabellana@ub.edu
authors.forename: Rosa
authors.initials: R
authors.lastname: Abellana
authors.forename: Carlos
authors.initials: C
authors.lastname: Ascaso
authors.forename: Josep L
authors.initials: JL
authors.lastname: Carrasco
authors.forename: Conxa
authors.initials: C
authors.lastname: Castell
authors.forename: Ricard
authors.initials: R
authors.lastname: Tresserras
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D013030:Spain / Q000453:epidemiology; D055815:Young Adult