title: The incidence of type 1 diabetes in the age group 0-39 years has not increased in Antwerp (Belgium) between 1989 and 2000: evidence for earlier disease manifestation.
abstract: OBJECTIVE
  A worldwide increase in the incidence of childhood type 1 diabetes has been observed. Because in various countries the majority of new type 1 diabetic patients are diagnosed in adulthood, we investigated whether the rising incidence of this disorder in children reflects a global increase in the incidence of diabetes or a shift toward earlier clinical presentation.
  
  
  METHODS
  The incidence of type 1 diabetes presenting before age 40 years was prospectively measured in the Antwerp district over a 12-year period (1989-2000). The completeness of ascertainment was evaluated by the capture-recapture method. Trends in incidence during the study period were analyzed by Poisson regression.
  
  
  RESULTS
  The incidence of type 1 diabetes diagnosed before age 40 years remained constant over the 12-year period, averaging 9.9 cases per 100,000 individuals per year. The incidence was similar in both sexes under age 15 years, but a marked male excess was noted for adult-onset disease, in particular after age 20 years, resulting in a male-to-female ratio of 0.9 under age 15 years vs. 1.6 thereafter (P = 0.001). During the 12-year observation period, there was a significant tendency toward increasing incidence under age 15 years at the expense of a decreasing incidence between ages 15 and 40 years (P = 0.025). The annual increase in incidence averaged 1.8% under age 15 years and 5.0% under age 5 years (P = 0.06).
  
  
  CONCLUSIONS
  Our results indicate that in Belgium, the increasing incidence of childhood type 1 diabetes-especially for children under age 5 years-is not attributable to a global increase in disease incidence, but rather to earlier clinical manifestation. The results suggest that an environmental factor may preferentially accelerate the subclinical disease process in young diabetes-prone subjects.
authors.affiliation: Diabetes Research Center, Free University, Brussels, Belgium.
authors.forename: Ilse
authors.initials: I
authors.lastname: Weets
authors.forename: Ivo H
authors.initials: IH
authors.lastname: De Leeuw
authors.forename: Marc V L
authors.initials: MV
authors.lastname: Du Caju
authors.forename: Raoul
authors.initials: R
authors.lastname: Rooman
authors.forename: Bart
authors.initials: B
authors.lastname: Keymeulen
authors.forename: Chantal
authors.initials: C
authors.lastname: Mathieu
authors.forename: Raoul
authors.initials: R
authors.lastname: Rottiers
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Daubresse
authors.forename: Danielle
authors.initials: D
authors.lastname: Rocour-Brumioul
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Pipeleers
authors.forename: Frans K
authors.initials: FK
authors.lastname: Gorus
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D001530:Belgium / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012044:Regression Analysis; D017678:Sex Distribution; D013997:Time Factors