Monday, 13 May 2013

Circumcision Does Not Prevent HPV Infection, RCT Data 'Inflated,' Study Finds

Researchers at the University of Washington find no relation between circumcision status and HPV infections, and that high HPV infection sites are ignored in previous studies, leading to false claims of the protection benefits of circumcision.

(NEW YORK, NY) — An original study at the University of Washington has found that male circumcision has no effect on human papillomavirus (HPV) infection rates. These results counter the widely publicized claims that intact males were more than 1.5 times likely to acquire HPV.
HPV is a sexually-transmitted virus known to cause cervical cancer in women. While HPV infections in women have been widely studied, HPV infections in men is an area lacking in research.
This University of Washington study tested for HPV infection at the head of the penis (or glans), on the shaft/scrotum skin, and in urine samples. Researchers found that the shaft/scrotum skin were the most likely sites of HPV infection in circumcised males, with a higher percentage of infections at these sites in circumcised males as compared to intact males.
Since shaft and scrotum skin together comprise the vast majority of the surface area of the penis in circumcised males, and are the most likely sites for HPV infection in circumcised males, any research done on circumcision status and HPV infection must necessarily include these sites.
However, most randomly-controlled trials (RCTs) only include testing of the head of the penis (or glans) for HPV infection. The widely-publicized RCT in Rakai, Uganda is one notable example. By not including all sites of infection, and in particular, by ignoring sites that have the highest chance of infection in circumcised males, researchers are producing false claims of protection.
Furthermore, the researchers of this U. of Wash. study note that most RCTs fail to account for the recovery period in circumcised participants who have to wait until their wounds heal, allowing time for the intact males to get infected. This  leads to further inflated claims of a protection benefit from circumcision.
In contrast to recent tightly-controlled trials such as the one in Rakai, Uganda, many surveys show that circumcised men have higher HPV infection rates. A United States national health survey on HPV infections found that the "percentage of circumcised men reporting a diagnosis of genital warts [caused by HPV infections] was significantly higher than uncircumcised men."

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