ORIGINAL ARTICLE Risk factors for urinary tract infection in children: A population-based study of 2856 children Premala Sureshkumar, 1,2 Mike Jones, 1,3 Robert G Cumming 2,4 and Jonathan C Craig 1,2 1 Centre for Kidney Research, NHMRC Centre for Clinical Research Excellence, The Children’s Hospital at Westmead, 2 School of Public Health, 4 Centre for Education and Research on Ageing, Concord Hospital, University of Sydney and 3 Department of Psychology, Macquarie University, Sydney, Australia Aim: To identify risk factors for urinary tract infection (UTI) in children to inform the development of preventative strategies. Method: A validated questionnaire covering demographic factors, perinatal, developmental, bowel and urinary history was sent to a cross- sectional sample of parents of elementary school children randomly selected from the first 4 years of school. UTI was ascertained by parental report, verified by cross-referencing with microbiological reports for all positive cases and 50 randomly selected negative cases. Results: Parents of 2856 children (mean age 7.3 years, range 4.8–12.8 years) responded. A total of 3.6% of children had a bacteriologically verified UTI, compared with 12.6% by parental report alone. Multivariate polychotomous logistic regression showed that a history of structural kidney abnormalities (odds ratio (OR) 15.7, 95% confidence interval 8.1–30.4), daytime incontinence (OR 2.6, 1.6–4.5), female gender (OR 2.4, 1.5–3.8), and encopresis (OR 1.9, 1.1–3.4) were independently associated with UTI. Daytime incontinence increased risk more in boys (8.3% vs. 1.2%) than girls (8.1% vs. 4.6%), and kidney problems increased risk in older compared with younger children (29% vs. 2% in 8 year olds, 0% vs. 4% in 4–6 year olds). Conclusions: Parents over-report UTI by about threefold. Effective treatment of daytime urinary incontinence and encopresis may prevent UTI in children, especially boys. Key words: questionnaire; risk factors; urinary tract infection. Urinary tract infection (UTI) in children is one of the most common bacterial illnesses in children. About 1% of boys and 3% of girls will be affected by at least one UTI by 11 years of age. 1 Recurrence of UTI is common in children, occurring in 12–30%, 1,2 with most recurrent infections occurring in the first 12 months of the previous infection. Many strategies to prevent UTI recurrence are recommended (long-term low-dose antibi- otics, reimplantation surgery, cranberry juice, reimplantation surgery for children with vesicoureteric reflux, circumcision), 3–6 but of these, only cranberry juice and circumcision have been shown to consistently reduce UTI. 5,6 Circumcision is only ap- propriate for boys, and has inherent complications, 7–11 and cranberry is only partially effective. Alternative preventative strategies are required. Some risk factors for UTI are well known, but mostly the causes for UTI are poorly understood. The strongest risk factors identified are renal tract abnormalities such as vesicoureteric reflux or a neurogenic bladder. An uncircumcised state in boys, female gender and a young age are also known risk factors. The aetiology of UTI is poorly understood because previous studies are generally small, not population-based, and lack a non-UTI control group. 12–19 The aim of our study was to determine the epidemiological risk factors for UTI in children at a population-based level, to inform the development of new strategies to prevent UTI. Methods Recruitment Recruitment occurred between May 2003 and December 2004. A random sample of 83 elementary schools was selected from the complete list of schools in the Sydney region provided by the New South Wales Department of Education, Australia. After obtaining approval from each individual school, a questionnaire was distributed to parents of all children in the first 4 years of the consenting schools. The parent-completed questionnaires were returned in the reply paid envelope provided to the Chil- dren’s Hospital at Westmead. Two reminders were sent at two weekly intervals to non-responders from participating schools that had consented to provide access to their class lists (about two-thirds of consenting schools). Key Points 1 Parents over-report urinary tract infection (UTI) by about threefold. 2 About 4% of children have at least one UTI by 7 years of age definitely and a further 8% may have a UTI. 3 Effective treatment of daytime urinary incontinence and enco- presis may prevent UTI in children, especially boys. Correspondence: Dr Premala Sureshkumar, Centre for Kidney Research, The Children’s Hospital at Westmead, Locked Bag 4001, Parramatta, NSW 2124, Australia. Fax: 61 2 9845 1491; email: premalas@chw.edu.au Accepted for publication 22 July 2008. doi:10.1111/j.1440-1754.2008.01435.x Journal of Paediatrics and Child Health 45 (2009) 87–97 © 2009 The Authors Journal compilation © 2009 Paediatrics and Child Health Division (Royal Australasian College of Physicians) 87