title: No association between routinely recorded infections in early life and subsequent risk of childhood-onset Type 1 diabetes: a matched case-control study using the UK General Practice Research Database.
abstract: OBJECTIVE
  To determine whether children with infections in early life (recorded routinely in general practice) have a reduced risk of Type 1 diabetes, as would be expected from the hygiene hypothesis.
  
  
  METHODS
  Children with Type 1 diabetes and up to 20 matched (on year of birth, sex and region) control subjects were selected from a cohort of children born in the UK at General Practice Research Database practices. For each child, the frequency of general practitioner consultations for infections and prescriptions for antibiotics in the first year of life were determined. Odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated using conditional logistic regression.
  
  
  RESULTS
  The main analysis included 367 case and 4579 matched control subjects. There was no evidence of any reduction in the subsequent risk of Type 1 diabetes in children with at least one infection in the first year of life (OR = 1.03, 95%CI 0.79, 1.34) or in children prescribed antibiotics in the first year of life (OR = 1.03, 95%CI 0.82, 1.29). Further analyses also revealed little evidence of a difference in subsequent risk of Type 1 diabetes after different types of infection in the first year of life (including gastrointestinal, conjunctivitis, otitis media and upper and lower respiratory tract). Analyses of infections in the first 2 years of life reached similar conclusions.
  
  
  CONCLUSIONS
  This study provides no evidence of an association between infections in early life and subsequent risk of childhood-onset Type 1 diabetes and therefore does not support the hygiene hypothesis.
authors.affiliation: School of Medicine and Dentistry, The Queen's University of Belfast, Belfast, UK.
authors.forename: C R
authors.initials: CR
authors.lastname: Cardwell
authors.forename: D J
authors.initials: DJ
authors.lastname: Carson
authors.forename: C C
authors.initials: CC
authors.lastname: Patterson
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D019992:Databases as Topic; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology*; D006801:Humans; D007223:Infant; D007239:Infections / Q000150:complications / Q000453:epidemiology*; D006113:United Kingdom / Q000453:epidemiology