Infections of the urinary tract (UTI) are regarded as being COMMON in the pediatric population .
The highest prevalence and greatest severity of UTIs in boys is prior to 6 months of age [316, 392], decreasing after infancy .
The younger the infant, the more likely and severe will be the UTI and the greater the risk of sepsis and death .
A preliminary study in Sweden has shown that early breastfeeding might also lower UTI , but, whilst worthwhile for many reasons, is less effective, and cannot be advocated as a replacement for circumcision.
Research showing an association of UTI with lack of circumcision is extensive and the link is now unequivocal. Most of the evidence has emerged over the past 20 years or so.
In 1982 it was reported that 95% of UTIs in boys aged 5 days to 8 months were in uncircumcised infants . This was confirmed by Wiswell  and a few years later Wiswell and colleagues found that in 5261 infants born at one US Army hospital, 4% of UTI cases were in uncircumcised males, but only 0.2% in those who were circumcised . This relatively captive population in Hawaii was said to be more reliable than the rate reported for hospital admissions . Wiswell then went on to examine the records for 427,698 infants (219,755 boys) born in US Armed Forces hospitals from 1975-79 and found that the uncircumcised had an 11-fold higher incidence of UTIs . During this decade the frequency of circumcision in the USA decreased from 84% to 74% and this decrease was associated with an increase in rate of UTI . Reviews by others in the mid-80s concluded there was a lower incidence in circumcised boys [213, 295]. The rate in girls was stable during the period it was increasing in boys, in whom circumcision was in a decline. In a 1993 study by Wiswell of 209,399 infants born between 1985 and 1990 in US Army hospitals worldwide, 1046 (496 boys) got UTI in their first year of life . The number was equal for boys and girls, but was 10 times higher for uncircumcised boys. Among the uncircumcised boys younger than 3 months, 23% had bacteremia, caused by the same organism responsible for the UTI.
In a study of 14,893 male infants aged less than 1 year who had been delivered during 1996 at Kaiser Permanente hospitals in Northern California, with 65% circumcised, 86% of the UTIs occurred in the uncircumcised boys [316, 318]. The mean cost of management in the boys was US$1111, being twice that of girls (US$542), reflecting a higher rate of hospital admission in uncircumcised males with UTI (27%) compared with females (7.5%). Mean age at admission also differed: 2.5 months for uncircumcised boys vs 6.5 months for girls. Total cost was 10-times higher for uncircumcised boys vs girls ($155,628 vs $15,466). There were 132 episodes of UTI in uncircumcised males, but only 22 in those who had been circumcised. Hospital admissions were 38 vs 4, respectively. Incidence during the first year of life was 2.2% in uncircumcised boys and just 0.22% in circumcised boys (odds ratio = 9:1). The incidence in the girls was 2%. In a commentary to this article, Wiswell points out that half of infants with acute pyelonephritis get renal scarring that then goes on to predispose to serious, life-threatening conditions later in life, meaning also a large, ongoing cost . Unlike adults, children, especially the very young are more likely to develop such renal injury and scarring. In fact imaging studies have shown that 50-86% of children with febrile UTI and presumed pyelonephritis have renal parenchymal defects , which persist. In a 27-year follow-up study risk of hypertension in these was 10-20%, and 10% were at risk of end-stage renal disease . UTIs are thus far from benign disorders of infancy. Moreover, the AAP Subcommittee on Urinary Tract Infections recommends a urine culture for any child under 2 with unexplained fever.
It should be noted that these studies gave figures for infants admitted to hospital for UTI, so that the actual rate would undoubtedly have been higher. Moreover, many fevers for which infants are admitted could have an undiagnosed UTI as the basis. The rate of UTI in uncircumcised boys may thus be higher than 2%.
The infection can travel up the urinary tract to affect the kidney, so explaining the higher rate of problems such as pyelonephritis and renal scarring (seen in 7.5% ) in uncircumcised children [299, 343]. In those with febrile UTI, 34%-70% have pyelonephritis . Moreover, as reported in Science in 2003, the E. coli responsible for UTI form impenetrable, protective "pods" on the walls of the bladder, so explaining the well-known ability of the bacteria responsible for UTI to persist in the face of robust host defences and antibiotic administration .
These and other reports - e.g., [78, 79, 126, 127, 155, 298, 299, 325, 336, 343] - all point to the benefits of circumcision in reducing UTI. Because UTIs are associated with long-term morbidity and potential mortality , prevention by measures such as infant male circumcision is highly desirable.
Wiswell performed a meta-analysis of all 9 studies that had been published up until 1992 and found that every one had observed an increase in UTI in the uncircumcised . The average was 12-fold higher and the range was 5- to 89-fold, with 95% confidence intervals of 11-14 . Meta-analyses by others have reached similar conclusions. A meta-analysis in 2005 of one (very small) randomized controlled trial , 4 cohort studies, and 7 case-control studies found 8-fold higher UTI in uncircumcised boys (95% CI: 5-13) . This slightly lower estimate is from inclusion of data for older boys, and the conservative recommendations by the authors of this paper have been criticized .
A large study in Canada of equal numbers of neonatally circumcised and uncircumcised boys saw rates of UTI and hospital admissions for UTI that were 4-fold higher in the uncircumcised . In Australia, a relatively small study in Sydney involving boys under 5 years of age (mean 6 months) found that 6% of uncircumcised boys got a UTI, compared with 1% of circumcised . A US study of 1025 febrile infants aged less than 2 months found the cause was UTI in 21.3% in uncircumcised boys, 2.3% in circumcised, and 5% in girls . Odds ratio of UTI associated with being uncircumcised was 10.4 (bias-corrected 95% CI: 4.7-31.4).
According to a personal communication from Dr Tom Wiswell in 2005: "The best data indicate that ~2.5% of uncircumcised boys will have a UTI during the first year of life. The lowest percentage among studies is ~1.1%. There are approximately 130 million births around the world annually. A little more than half are boys. Of these 65 million boys, probably 80%-90% or more are not circumcised (52-58 million). Thus, worldwide there would be anywhere from 560,000 to 1.45 million uncircumcised boys with UTIs annually. This does not include older males who are also more prone to have UTIs, but at much lower rates."
The benefit appears to extend beyond childhood and into adult life. In a study of men aged, on average, 30 years, and matched for race, age and sexual activity, the circumcised had a lower rate of UTI .