More Total Partners, Injecting Drugs Tied to Anal HPV-16 in SF MSM

Having more than 200 lifetime male sex partners raised chances of anal infection with human papillomavirus (HPV) type 16, the primary cause of anal cancer, in a study of HIV-positive men who have sex with men (MSM) in San Francisco. Injection drug use boosted chances of anal HPV-16 infection 50%. HIV-positive MSM run an increased risk of anal cancer compared with the general population. HPV-16 is strongly associated with anal intraepithelial neoplasia and cancer. Because risk factors for anal HPV-16 remain poorly understood, researchers conducted this study of 348 HIV-positive MSM entering a 4-year prospective cohort study.

At the first study visit, men completed a detailed sexual behavior questionnaire and gave an anal swab for detection of HPV-16 and other HPV types. Researchers used log-binomial multivariable models to identify risk factors for anal HPV-16 infection.

Of the 348 HIV-positive MSM men studied, 92% carried at least one HPV genotype, 80% had at least one cancer-causing HPV type, and 42% had HPV-16.

Two factors were associated with a lower risk of HPV-16 infection—non-Hispanic white race and a higher level of education. Having 201 to 1000 lifetime male sex partners (versus 1 to 200) raised the risk of HPV-16 infection 60% (relative risk 1.6, 95% confidence interval [CI] 1.1 to 2.4, P = 0.01). Injection drug use raised the risk of HPV-16 infection 50% (relative risk 1.5, 95% CI 1.2 to 1.9, P = 0.003).

"The prevalence of anal HPV infection, including HPV 16, is high in HIV-positive MSM," the authors conclude. They advise that "HIV-positive MSM should be counseled about the risk associated with increased partners and injection drug use."

Source: Alexandra L. Hernandez, Jimmy T. Efird, Elizabeth A. Holly, J. Michael Berry, Naomi Jay, Joel M. Palefsky. Risk factors for anal human papillomavirus infection type 16 among HIV-positive men who have sex with men in San Francisco. JAIDS. 2013; 63: 532-539.

Written by Mark Mascolini on behalf of the International AIDS Society