title: The age at diagnosis of type 1 diabetes continues to decrease in Belgian boys but not in girls: a 15-year survey.
abstract: BACKGROUND
  The age at clinical onset of type 1 diabetes is decreasing. Preliminary Belgian data suggested that this anticipation occurred preferentially in boys. We investigated whether this gender-specific anticipation could be confirmed over a 15-year observation period.
  
  
  METHODS
  In Antwerp, we studied incidence trends between 1989 and 2003 in 746 type 1 diabetic patients under age 40. For 2928 antibody-positive patients diagnosed nationwide during the same period, age at diagnosis was analysed according to gender and calendar year.
  
  
  RESULTS
  In Antwerp, the incidence of type 1 diabetes under age 15 increased significantly with time from 10.9/100 000/year in 1989-1993 to 15.8/100 000/year in 1999-2003 (p = 0.008). The rising incidence in children was largely restricted to boys under age 10 where the incidence more than doubled during the 15-year period (6.8/100 000/year in 1989-1993 vs 17.2/100 000/year in 1999-2003; p < 0.001). Such an increase was not found in girls under age 10 (p = 0.54). This selective trend toward younger age at diagnosis in boys was confirmed in the larger group of Belgian patients where the median age at diagnosis decreased in boys-but not in girls-from 20 years in 1989-1993 to 15 years in 1999-2003 (p < 0.001).
  
  
  CONCLUSIONS
  Over a 15-year observation period, a selective anticipation of clinical onset of type 1 diabetes was found in boys but not in girls. This suggests that an environmental factor may preferentially accelerate the sub-clinical disease process in young boys.
authors.affiliation: Diabetes Research Center, Free University Brussels, Belgium. ilse.weets@uzbrussel.be
authors.forename: I
authors.initials: I
authors.lastname: Weets
authors.forename: R
authors.initials: R
authors.lastname: Rooman
authors.forename: M
authors.initials: M
authors.lastname: Coeckelberghs
authors.forename: C
authors.initials: C
authors.lastname: De Block
authors.forename: L
authors.initials: L
authors.lastname: Van Gaal
authors.forename: J-M
authors.initials: JM
authors.lastname: Kaufman
authors.forename: B
authors.initials: B
authors.lastname: Keymeulen
authors.forename: C
authors.initials: C
authors.lastname: Mathieu
authors.forename: E
authors.initials: E
authors.lastname: Weber
authors.forename: D G
authors.initials: DG
authors.lastname: Pipeleers
authors.forename: F K
authors.initials: FK
authors.lastname: Gorus
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D001530:Belgium / Q000453:epidemiology; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology*; D005260:Female; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D008297:Male; D012727:Sex Characteristics