Men who are circumcised and use condoms consistently may have a reduced risk of carrying human papillomavirus (HPV) on their penises. In analyses of data from a public sexually transmitted disease (STD) clinic in Tucson,1 HPV was significantly less likely to be detected on the penises of circumcised men than on those of uncircumcised men (odds ratio, 0.3). Men who reported having always used condoms in the past three months were significantly less likely than nonusers to have HPV detected (0.4).
Study participants were 393 clinic attendees aged 18 or older who were recruited in 2000-2001 and completed a questionnaire about their demographic background, sexual behaviors and risk factors for STDs. Examinations were performed to evaluate clinical characteristics and to swab the surface of the penis for HPV testing. Detection was established if a skin sample contained HPV DNA. The researchers used chi-square tests and multivariate logistic regressions to assess relationships between participants' characteristics and the detection of any HPV and of oncogenic and nononcogenic strains of the virus.
Twenty-eight percent of men tested positive for any type of HPV. In univariate analyses adjusted for age, a significantly lower proportion of 25-29-year-olds than of 18-24-year-olds tested positive for the virus (20% vs. 34%). HPV detection was significantly less common among whites than among Hispanics and participants of other races and ethnicities (21% vs. 33-34%); among men who had some college education than among those who had a high school education or less (21% vs. 35%); and among participants who were circumcised than among those who were not (20% vs. 41%). Men who reported a coital frequency of 30 or more times per month during the past three months tested positive for penile HPV in significantly higher proportions than those who had not had sex at all (52% vs. 24%). HPV detection was also significantly more common among men who had genital warts at the time of the study than among those who did not (46% vs. 27%).
Univariate analyses of condom use and HPV status revealed that the proportion of men who had HPV detected was significantly lower among those who had sometimes used condoms during the past three months than among those who had never used them (25% vs. 37%). Participants who had used condoms at last anal intercourse tested positive for HPV at a significantly lower frequency than did those who had not used protection (14% vs. 41%). HPV detection was also significantly less common among men who sometimes or always used condoms with their steady partner than among those who never used them (15-24% vs. 40%).
Multivariate analyses adjusted for behavioral and clinical factors indicated that circumcised men and consistent condom users were significantly less likely to have HPV detected than were uncircumcised men and nonusers, respectively (odds ratios, 0.3 and 0.4). Participants who had always used condoms in the past three months were significantly less likely than those who had never used them to test positive for HPV (0.4). Having genital warts was significantly associated with elevated odds of HPV detection (2.5), as was a coital frequency of more than 30 times per month in the past three months (3.7). The odds of detection increased significantly with coital frequency.
In multivariate analyses stratified by HPV type, only circumcision remained significantly linked to reduced odds of oncogenic and nononcogenic HPV detection (odds ratios, 0.4 for both). The odds of having nononcogenic HPV detected were significantly elevated among men with genital warts (4.4) and significantly decreased among those who had used a condom at last anal intercourse (0.3). The relationship between HPV detection and a coital frequency of more than 30 times per month persisted in analyses limited to oncogenic strains of the virus (5.0), as did the trend associated with coital frequency and men's odds of HPV detection. Having always used condoms in the past three months was significantly associated with decreased odds of oncogenic HPV detection (0.2).
The researchers acknowledge that their study is limited because it included self-reported condom use data, used skin swabs for HPV testing and was based on a clinic population, who may be at high risk. According to the authors, their findings "suggest that 'classic' risk factors for HPV [such as cumulative number of partners and age at first intercourse] do not apply in men." Moreover, they say, "for prophylactic HPV vaccine efforts, targeted education campaigns, and other future cancer prevention endeavors to be successful, comprehensive knowledge about the epidemiology of HPV in men must be acquired through further studies."
1. Baldwin SB et al., Condom use and other factors affecting penile human papillomavirus detection in men attending a sexually transmitted disease clinic, Sexually Transmitted Diseases, 2004, 31(10):601-607.