Comparison of age-specific patterns of sexual behaviour and anal HPV prevalence in homosexual men with patterns in women.

OBJECTIVES: Anal human papillomavirus (HPV) is highly prevalent in men who have sex with men (MSM) of all ages, whereas cervical HPV declines with age. We explore the hypothesis that different sexual behavioural patterns are the basis of this difference in age distribution.

METHODS: Published data on age-specific HPV prevalence for women (cervical HPV) were extracted from a large meta-analysis and for MSM (anal HPV) from the EXPLORE study of HIV-negative MSM. Age-specific data on recent sexual activity were extracted from two behavioural surveys: the second Australian Study of Health and Relationships survey and the 2013 Gay Community Periodic Survey.

RESULTS: At least 50% of MSM at all ages reported more than one sexual partner in the past 6 months. In comparison, 33% of women aged 16-19 years reported more than one partner over the past year. This decreased to 19% and 6% in women aged 20-29 and 30-39 years, respectively, and to fewer than 5% of women in older age groups. Prevalent anal HPV was detected in over 50% of MSM in each age group. Prevalence did not decline with age. In contrast, there was a steady decrease in cervical HPV prevalence with age. Cervical HPV prevalence fell from 23% among North American women aged <25 years to 3% in women aged ≥65 years.

CONCLUSIONS: In contrast to the decreasing prevalence with age among heterosexual women, the high prevalence and lack of decline in prevalent anal HPV among older MSM are likely to be related to continuing high rates of newly acquired HPV infection from ongoing sexual exposure through new partners.