The association between body mass index and anal canal human papillomavirus prevalence and persistence: the HIM study

Background: While receptive anal sex is an established risk factor for anal human papillomavirus (HPV) infection and squamous cell carcinoma of the anus (SCCA), people with anal HPV infection and SCCA commonly report no lifetime receptive anal sex suggesting other factors may also increase risk for anal HPV infection and persistence. Given potential associations between obesity and conditions that may cause perianal or anal canal lesions, we hypothesized that body mass index (BMI) was associated with HPV infection. Methods: Genotyping for 36 HPV types was conducted on anal canal specimens from men, ages 18-70, from Brazil, Mexico, and the USA. Eligibility included no history of genital warts or HIV. Evaluable specimens were collected from 328 men having sex with men (MSM) and 1348 men having sex with women (MSW) who reported no lifetime receptive anal sex. Prevalence of anal HPV infection and six-month persistence by BMI were estimated in addition to adjusted prevalence ratios for the association between BMI and HPV infection. Results: Among MSW, obese men had a higher prevalence of HPV-16 in the anal canal (3.1%), compared to normal weight men (1.3%) although 95% CI overlapped. Among MSM, prevalence of HPV decreased with increasing BMI. A similar pattern was observed for persistence. After adjustment for confounders, obese MSW had 2.4 times higher odds of HPV-16 compared to normal weight men. Conclusions: BMI may be positively associated with anal HPV (especially HPV-16) among MSW and negatively associated with anal HPV among MSM which supports continued universal HPV vaccination programs.