Abstract
Anal high-risk human papillomavirus (hr-HPV) infection is widely considered a cause of anal cancer. However, epidemiological data are quite limited in Japan. This study investigated anal HPV infections and cytological abnormalities among MSM with or without HIV infection. Anal swabs were obtained, and cytological results were examined. Hybrid capture-based methodology was used for hr-HPV genotyping. The exclusion criterion was a history of vaccination against HPV. 644 subjects participated, and the overall prevalence of hr-HPV was 59.7% (95% CI 54.7-62.3), HIV-infected had higher prevalence than HIV-uninfected (68.9% vs 40.6%) p < .001. Among hr-HPV-infected participants, 82.8% (312/377) were infected with at least one of 9 valent vaccine-covered hr-HPV genotypes. From regression analysis, detection of abnormal cytology correlated positively with HIV infection (OR 2.17 [95% CI 1.51-3.13]), number of hr-HPV genotypes infected (OR 1.83 [1.59-2.10]), history of STI (OR 1.58 [1.14-2.22]) and No. of lifetime sexual partners (OR 1.56 [1.10-2.21]), albeit multivariate analysis identified the number of detected hr-HPV genotypes (adjusted OR 1.78 [1.54-2.06]) as the independent risk factor for abnormal cytology. High rates of anal hr-HPV infection, especially 9-valent HPV vaccine-preventable hr-HPV were detected among our MSM participants in Japan. HPV vaccination should also be encouraged for MSM in Japan.