title: Can risk factors for infectious illnesses in children at day care centres be identified?
abstract: BACKGROUND
  The risk factors for febrile, respiratory, and gastrointestinal illnesses in preschool children at day care centres have not been adequately identified and may differ between countries.
  
  
  METHODS
  In this repeated cross-sectional and longitudinal study of children at day care centres, we analyzed various potential risk factors for infectious illnesses using a mixed effect hierarchical Poisson regression model. The results of the analyses and the incidence rates of these illnesses are reported herein.
  
  
  RESULTS
  The study lasted 2.5 y (2000-2003) and was divided into five 6-month periods (seasons). Nine hundred and seventeen children participated, and their mean age within each season was 3.6-4.1 y. The only consistent risk factors identified were young age and winter season. No consistent risk factors at the day care centres (facilities or hygiene practices) were identified. The incidences of the febrile, respiratory, and gastrointestinal illnesses varied significantly between seasons (winter/summer) and between age groups.
  
  
  CONCLUSIONS
  Risk factors of infectious illnesses are difficult to identify and because they may vary between countries, international recommendations on expensive intervention strategies are not justifiable. Rates of respiratory illnesses in Icelandic preschool children appear higher than in other countries, but rates of gastrointestinal illnesses lower.
authors.affiliation: Directorate of Health, and Department of Paediatrics Landspitali University Hospital, Austurstrond 5, Seltjarnarnes, Iceland. thorolfur@landlaeknir.is
authors.forename: Thorolfur
authors.initials: T
authors.lastname: Gudnason
authors.forename: Birgir
authors.initials: B
authors.lastname: Hrafnkelsson
authors.forename: Brynja
authors.initials: B
authors.lastname: Laxdal
authors.forename: Karl G
authors.initials: KG
authors.lastname: Kristinsson
mesh_terms: D000375:Aging; D002648:Child; D002656:Child Day Care Centers; D002675:Child, Preschool; D003141:Communicable Diseases / Q000453:epidemiology* / Q000635:transmission*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D012307:Risk Factors; D012621:Seasons; D054063:Superior Sagittal Sinus; D013997:Time Factors