Sexual behaviours associated with incident high-risk anal human papillomavirus among gay and bisexual men.

Objective: High-risk human papillomavirus (HRHPV) causes anal cancer, which disproportionately affects gay and bisexual men (GBM). We examined sexual behaviours associated with incident anal HRHPV in an observational cohort study of GBM in Sydney, Australia.
Methods: GBM aged 35 years and above were enrolled in the Study of the Prevention of Anal Cancer. Detailed information on sexual practices in the last 6 months, including receptive anal intercourse (RAI) and non-intercourse receptive anal practices, was collected. Anal human papillomavirus (HPV) testing was performed at the baseline and three annual follow-up visits. Risk factors for incident HRHPV were determined by Cox regression using the Wei-Lin-Weissfeld method.
Results: Between 2010 and 2015, 617 men were recruited and 525 who had valid HPV results at baseline and at least one follow-up visit were included in the analysis. The median age was 49 years (IQR 43-56) and 188 (35.8%) were HIV-positive. On univariable analysis, incident anal HRHPV was associated with being HIV-positive (p<0.001), having a higher number of recent RAI partners regardless of condom use (p<0.001 for both), preference for the receptive position during anal intercourse (p=0.014) and other non-intercourse receptive anal sexual practices, including rimming, fingering and receptive use of sex toys (p<0.05 for all). In multivariable analyses, being HIV-positive (HR 1.46, 95% CI 1.09 to 1.85, p=0.009) and reporting condom-protected RAI with a higher number of sexual partners (p<0.001) remained significantly associated with incident HRHPV. When stratified by recent RAI, non-intercourse receptive anal practices were not associated with incident HRHPV in men who reported no recent RAI.
Conclusion: GBM living with HIV and those who reported RAI were at increased of incident anal HRHPV. Given the substantial risk of anal cancer and the difficulty in mitigating the risk of acquiring anal HRHPV, HPV vaccination should be considered among sexually active older GBM.
Trial Registration Number: ANZCTR365383.
Competing Interests: Competing interests: AEG has received honoraria and research funding from CSL Biotherapies and honoraria and travel funding from Merck, and sits on the Australian advisory board for the Gardasil HPV vaccine. IMP has received travel funding from Seqiris, the distributor of Gardasil vaccine in Australia. CKF owns shares in CSL Biotherapies. MNP received research funding from Gilead, Janssen, Celgene, BMS and ViiV for research outside the submitted work. SMG has received Merck Global Advisory Board fees, grant support through her institution and lecture fees from Merck. All other authors have no conflicts of interest to declare.
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