Human papillomavirus (HPV) is the cause of genital warts, and some subtypes of the virus can cause cancer. Now, researchers report that circumcision and regular condom use may prevent genital warts on pensies.

Although HPV is the main cause of cervical and anal cancer, few studies have looked at risk factors for penile HPV infection in men, Dr. Susie Baldwin, from the VA Sepulveda Ambulatory Care Center in California, and colleagues point out in the medical journal Sexually Transmitted Diseases.

To investigate this issue, the researchers studied 393 men who attended an STD clinic in Arizona between July 2000 and January 2001. The team gave the men questionnaires and tested swabs of the penis for DNA from HPV, to see if they were infected.

The likelihood of detecting HPV was over three times higher for men who engaged in sexual intercourse more than 30 times per month compared with those who had intercourse no more than 5 times per month.

As noted, circumcision and regular condom use seemed to protect against penile HPV. Circumcised men were one-third as likely as uncircumcised men to be infected, while always using a condom halved the risk compared with never using a condom.

The increasing rate of HPV-related cancers in the US "attests to the importance of understanding HPV not only in women, but in men, who serve as vectors of this ubiquitous virus and potentially as reservoirs," the researchers conclude.