Background: Although the primary cause of anal cancer is human papillomavirus (HPV) infection in the anal canal, little attention has been paid to the epidemiology of anal HPV infection in men who have sex with women (MSW).
Methods: Exfoliated cells from the anal canal of 902 MSW in Brazil (São Paulo), Mexico (Cuernavaca), and the United States (Tampa) were tested for HPV DNA.
Results: The prevalence of HPV infection in the anal canal (12.0%) was similar among MSW in each city (P=.77), whereas 7.0% had infection with oncogenic types. Men in Tampa had a 4-fold higher prevalence of infection with HPV type 16 (HPV-16) than that among men in São Paulo or Cuernavaca (P<.001). Duration of relationship with a primary sex partner and ever having oral or anal sex with a man was associated with infection with any HPV type and with any oncogenic type, whereas lifetime number of female sex partners was associated with infection with any HPV type.
Conclusions: Anal canal HPV infection is commonly found among MSW, and the prevalence of infection with HPV-16 may differ substantially by geography. Men who have a larger lifetime number of female sex partners, who are in a sexual relationship of <1 year in duration, and who have a history of oral or anal sex with men were most likely to have an anal HPV infection.