Human papilloma virus (HPV) is one of the most commonly diagnosed STIs, with over 630 million HPV infections worldwide and an overall prevalence between 9-13% . A systematic review documented that the prevalence of HPV infection varies among men . However, these wide estimates have been attributed to different sampling methods [2, 3], as well as to differences in the populations studied . Regarding HPV-related cancers, worldwide studies have reported presence of HPV infection for oropharyngeal , anal  and penile cancers . Despite the reported global burden of HPV infection and HPV-related cancers in men , few studies have evaluated HPV and HPV-related cancer knowledge [8, 9] particularly among high-risk men.
Although knowledge is not a direct predictor of health behavior , it is mediated by attitudes, risk perceptions, social influence and self-efficacy . Thus, acquiring knowledge is a key first step to the success of any health education intervention. Although there has been increased attention to HPV awareness and knowledge in the literature [12, 13], most of the available research has focused on women [11, 14, 15]. Studies in men, particularly among those of Hispanic origin, are scarce. Among the few studies that have evaluated gender differences, men have lower knowledge about HPV compared to women [16, 17].
In Puerto Rico (PR), despite the HIV epidemic and documented high-risk sexual practices in population-based studies [18, 19], there is limited epidemiological and behavioral research on knowledge of HPV infection, particularly among high-risk groups; this may delay the development of effective interventions to reduce the burden of HPV infection. This kind of research is necessary, given that epidemiological evidence indicates that men in PR, particularly HIV+ men, have higher rates of HPV-related cancers compared to the general population of PR . Therefore, in order to understand the determinants of knowledge of HPV infection, it is necessary to evaluate high-risk groups, particularly individuals whose average rate of acquisition of new sexual partners is sufficiently high to maintain increasing numbers of secondary infections. STI clinics can be an ideal setting for reaching these high-risk groups . Studies in STI clinics have reported high prevalence estimates of HPV infection; but knowledge in patients from these settings is limited [22–24]. This study aims to describe the proportion of men that attend an STI clinic in PR who are aware of HPV, determine their level of knowledge about HPV infection, and identify correlates of HPV knowledge within this group.