title: Effect of circumcision on incidence of urinary tract infection in preschool boys.
abstract: OBJECTIVE
  To determine whether circumcision decreases the risk of symptomatic urinary tract infection (UTI) in boys less than 5 years of age.
  
  
  METHODS
  A case-control study (1993 to 1995) in the setting of a large ambulatory pediatric service. Case subjects and control subjects were drawn from the same population. One hundred forty-four boys less than 5 years of age (median age, 5.8 months) who had a microbiologically proven symptomatic UTI (case subjects), were compared with 742 boys (median age, 21.0 months) who did not have a UTI (control subjects). The proportion of case and control subjects who were circumcised in each group was compared with the use of the chi-square test, with the strength of association between circumcision and UTI expressed in terms of an odds ratio. To determine whether age was a confounder or an effect-modifier, we stratified the groups by age (< 1 year; > or = 1 year) and analyzed by the method of Mantel-Haenszel.
  
  
  RESULTS
  Of the 144 preschool boys with UTI, 2 (1.4%) were circumcised, compared with 47 (6.3%) of the 742 control subjects (chi-square value = 5.6; p = 0.02; odds ratio, 0.21; 95% confidence intervals, 0.06 to 0.76). There was no evidence that age was a confounder or modified the protective effect of circumcision on the development of UTI (Mantel-Haenszel chi-square value = 6.0; p = 0.01; combined odds ratio, 0.18; 95% confidence intervals, 0.05 to 0.71; Breslow-Day test of homogeneity chi-square value = 0.6; p = 0.4).
  
  
  CONCLUSIONS
  Circumcision decreases the risk of symptomatic UTI in preschool boys. The protective effect is independent of age.
authors.affiliation: Department of Nephrology, Royal Alexandra Hospital for Children, Sydney, Australia.
authors.forename: J C
authors.initials: JC
authors.lastname: Craig
authors.forename: J F
authors.initials: JF
authors.lastname: Knight
authors.forename: P
authors.initials: P
authors.lastname: Sureshkumar
authors.forename: E
authors.initials: E
authors.lastname: Mantz
authors.forename: L P
authors.initials: LP
authors.lastname: Roy
mesh_terms: D017677:Age Distribution; D000367:Age Factors; D001315:Australia; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002675:Child, Preschool; D002944:Circumcision, Male; D015169:Colony Count, Microbial; D006801:Humans; D007223:Infant; D008297:Male; D016017:Odds Ratio; D014552:Urinary Tract Infections / Q000517:prevention & control*