title: Prevalence of and risk factors for anal human papillomavirus infection in men who have sex with women: a cross-national study.
abstract: 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.
authors.affiliation: H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida 33612, USA. alan.nyitray@moffitt.org
authors.forename: Alan G
authors.initials: AG
authors.lastname: Nyitray
authors.forename: Dan'elle
authors.initials: D
authors.lastname: Smith
authors.forename: Luisa
authors.initials: L
authors.lastname: Villa
authors.forename: Eduardo
authors.initials: E
authors.lastname: Lazcano-Ponce
authors.forename: Martha
authors.initials: M
authors.lastname: Abrahamsen
authors.forename: Mary
authors.initials: M
authors.lastname: Papenfuss
authors.forename: Anna R
authors.initials: AR
authors.lastname: Giuliano
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001004:Anus Diseases / Q000453:epidemiology / Q000821:virology*; D001938:Brazil / Q000453:epidemiology; D005260:Female; D005838:Genotype; D020010:Heterosexuality; D006801:Humans; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D027383:Papillomaviridae / Q000235:genetics; D030361:Papillomavirus Infections / Q000453:epidemiology* / Q000821:virology; D015995:Prevalence; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult