title: Seasonal variation of type 1 diabetes mellitus diagnosis in Greek children.
abstract: OBJECTIVE
  The aim of the study was to investigate the seasonal variation of type 1 diabetes mellitus (T1DM) diagnosis in Greek children.
  
  
  METHODS
  The study group consisted of 1148 patients (604 males and 544 females) who were diagnosed with T1DM during the period 1978-2008. The mean age at diagnosis was 8.32 ± 5.01 years. The date of birth and the date at diagnosis were recorded from the patients' files.
  
  
  RESULTS
  Significantly more children were diagnosed with T1DM during the cold months as opposed to the warm months (p=0.001), with no differences between boys and girls. When children were categorized into the age groups ≤ 3 and >3 years old the seasonal variation pattern was different in younger ages suggesting that environmental factors which possibly interfere with T1DM diagnosis may have a different effect in those of younger than older age. With regard to date of birth, significantly more children with diabetes were born during the Spring-Summer than in Autumn-Winter (p=0.004).
  
  
  CONCLUSIONS
  The results of the study support the concept of seasonality in T1DM diagnosis, implying a possible relationship between clinical expression of T1DM and various climatic factors. Seasonal variation at diagnosis appears to be different in younger compared to older children.
authors.affiliation: Diabetes Center, Department of Pediatrics, Faculty of Nursing, University of Athens at the P & A Kyriakou Children's Hospital, Athens, Greece. canastasiou@env.aegean.gr
authors.forename: Maria I
authors.initials: MI
authors.lastname: Kalliora
authors.forename: Andriani
authors.initials: A
authors.lastname: Vazeou
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Delis
authors.forename: Evangelos
authors.initials: E
authors.lastname: Bozas
authors.forename: Ioanna
authors.initials: I
authors.lastname: Thymelli
authors.forename: Christos S
authors.initials: CS
authors.lastname: Bartsocas
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006115:Greece / Q000453:epidemiology; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D012621:Seasons