Uncircumcised baby boys have infections of the kidney, bladder and urethra at nearly 10 times the rate of circumcised boys, and over a lifetime, uncircumcised males are four times more likely to experience one, according to a new meta-analysis from Australia.
Circumcision "provides considerable protection and over the life span makes about a three- to four-fold difference by our prediction, which is quite striking in public health terms," lead study author Brian Morris of the University of Sydney.
Dr Morris and a colleague examined 22 studies published between 1987 and 2012 that included a total of 407 902 males across the globe, a quarter of whom were uncircumcised.
Breaking down the results by age, they calculated that the likelihood of a UTI between birth and one year of age is 9.9 times higher in uncircumcised boys compared to circumcised boys. Between ages one and 16, uncircumcised boys are at 6.6 times higher risk, and after age 16 their risk is 3.4 times that of uncircumcised men.
Based on those findings, the researchers projected one UTI is prevented with every four circumcisions, "which is astronomical," Dr Morris said.
The younger the infant, the more serious a UTI can be, the researchers note in their report, which was published online in the Journal of Urology. Side effects of a UTI in infants can include kidney scarring, fever, pain and blood infections.
Health experts have mostly framed circumcision as a public health preventive measure focused on HIV and other sexually transmitted diseases.
In August, the American Academy of Pediatrics for the first time stated that the health benefits of circumcision outweigh the risks, but added that the decision to circumcise a child remains with parents.
The US Centers for Disease Control and Prevention is currently evaluating the potential health impact of circumcision, according to a spokeswoman, but any recommendations that come of that will also be voluntary, she said.
What the study found
The estimated health benefit Dr Morris and his colleague found was several times larger than what was projected in two previous studies, which suggested 111 or 195 circumcisions would be needed to prevent one case of UTI in the first year of life.
One expert questioned the new findings based on the researchers' methods.
Dr Zbys Fedorowicz, director of the Bahrain branch of the UK Cochrane Center, a non-profit organisation that evaluates medical studies, said that the 22-study analysis combined different types of studies and the researchers failed to assess their quality.
"It doesn't mean to say that these guys are necessarily wrong, it's just that we don't know because the methodological approach that they used isn't thorough enough, it's not transparent, it's not reproducible and it's not clear," Dr Fedorowicz said.
In November, Dr Fedorowicz and colleagues published a report concluding that no existing study that examined the risk of urinary tract infections and circumcision was of high enough quality for any recommendation.
Dr Robert Van Howe, a paediatrician at Michigan State University College of Human Medicine and vocal critic of circumcision, also found the new study problematic.
Dr Van Howe said that diagnostic criteria for urinary tract infections differ between researchers and that the cost/ benefit analysis of circumcision as a preventive tool for infections doesn't add up.
Using the earlier study results, at $200 each circumcision, preventing one urinary tract infection would cost $40 000, "which you can treat with an $18 antibiotic; it's overkill," Dr Van Howe said.
"You would think we have long lists for dialysis in men because they're not circumcised, but it just isn't a problem, it's fear mongering," he told Reuters Health.
A middle ground might be to let boys decide for themselves at age 14 or 16 to become circumcised, Dr Van Howe suggested. "You can leave this choice up to the person who has to live with the consequences."
Dr Morris maintains that the study sends "a really strong signal for advocacy of circumcision as a public health intervention in reducing these various - and in many cases very serious - conditions over the lifetime."
(Reuters Health , December 2012)
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