title: IA-2A positivity rate at manifestation of type 1 diabetes mellitus in Slovak children culminates in September.
abstract: BACKGROUND
  New cases of type 1 diabetes mellitus (DM1) in Slovak children accumulate in late summer, autumn and winter.
  
  
  OBJECTIVE
  Children manifesting the disease in these seasons have higher autoantibody positivity than those first diagnosed in spring or summer.
  
  
  METHODS
  One hundred and fifty Slovak children (and adolescents), aged 1-14 (15-17) years at the manifestation of DM1, born 1978-2000, with the disease manifested 1989-2001, were investigated at diagnosis by IA-2A, GADA and IAA autoantibody positivity, using standard radioimmunoassay procedures. The resulting risk score values (0-1) were related to calendar days of diagnosis. Their annual, semi-annual and quarterly periodicity was tested using Halberg's cosinor regression.
  
  
  RESULTS
  Only IA-2A positivity at the time of diagnosis showed significant seasonal cycling, with the acme around the autumn equinox and with the nadir in spring. There was no increase of this positivity in winter.
  
  
  CONCLUSIONS
  The maximum autoantibody levels were found for those manifesting the disease in late summer and early autumn--the only time of year in Slovakia when both the numbers of births of future diabetic children as well as those of manifestation of new cases are significantly above average.
authors.affiliation: 1st Pediatric Clinic, Faculty of Medicine, Comenius University, Bratislava, Slovak Republic.
authors.forename: D
authors.initials: D
authors.lastname: Michalková
authors.forename: M
authors.initials: M
authors.lastname: Mikulecký
authors.forename: E
authors.initials: E
authors.lastname: Tomecková
mesh_terms: D000293:Adolescent; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003627:Data Interpretation, Statistical; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology* / Q000276:immunology*; D005968:Glutamate Decarboxylase / Q000097:blood / Q000276:immunology; D006801:Humans; D007223:Infant; D007267:Injections; D007328:Insulin / Q000008:administration & dosage / Q000097:blood / Q000276:immunology; D010179:Pancreas / Q000201:enzymology / Q000276:immunology; D010507:Periodicity; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000097:blood / Q000276:immunology*; D011863:Radioimmunoassay / Q000379:methods; D012621:Seasons; D018154:Slovakia / Q000453:epidemiology
chemical_list: D001323:Autoantibodies; D007328:Insulin; C024211:islet cell antibody; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; D005968:Glutamate Decarboxylase