Sex Differences in the Incidence and Clearance of Anogenital Human Papillomavirus Infection in Liuzhou, China: An Observational Cohort Study.

BACKGROUND:Human papillomavirus (HPV) causes anogenital warts and cancers in men and women. However, little is known about sex differences regarding the natural history of anogenital HPV infection. METHODS:Starting in May 2014, an observational cohort study including 2309 men and 2378 women aged 18-55 years was conducted in Liuzhou, China. Samples from anogenital sites were tested for HPV genotypes by multicolor real-time polymerase chain reaction and melting curve analysis biannually for ~1 year. RESULTS:The incidence of oncogenic HPV infection was similar in men and women (10.3 and 11.5/1000 person-months; P = .275), whereas the incidence of HPV-6/11 infection was higher in men than in women (2.0 vs 1.1; P = .018). The incidence of both oncogenic HPV and HPV-6/11 infections was significantly higher in women in the 18- to 25-year age group than in the older age groups (P = .006 and .011, respectively), whereas it did not vary by age among men (P = .552 and .425, respectively). Additionally, men were more likely than women to clear oncogenic infections (101.5 vs 58.6/1000 person-months; P < .001), but no significant difference was found in the clearance of HPV-6/11 by sex (111.7 vs 84.8; P = .266). The median time to clearance of oncogenic type and type 6/11 infections was not age dependent for either sex (all P > .05). CONCLUSIONS:The natural history of oncogenic and nononcogenic HPV infection differs by sex, which implies that sex-specific vaccination strategies should be considered for oncogenic and nononcogenic HPV. CLINICAL TRIALS REGISTRATION:NCT02188004.