Oral sexual behaviors and the prevalence of oral human papillomavirus infection.

Abstract

In this issue of the Journal, D’Souza et al. [1] demonstrate that oral sexual behaviors are associated with the detection of prevalent oral human papillomavirus (HPV) infection. With their study, D’Souza and colleagues have taken an additional step toward improving our understanding of the epidemiologic profile of oral HPV transmission. HPV is an important human carcinogen that is increasingly implicated in human cancers occurring at multiple anatomical sites [2]. Over the past decade, there has been accumulating molecular and epidemiologic evidence demonstrating that HPV causes a subset of head and neck cancers, specifically in the oropharynx [3, 4]. This evidence mandates the need for additional novel research along multiple areas of the disease continuum. Important research topics include (1) elucidating the natural history and epidemiologic profile of oral HPV infection in healthy individuals, (2) determining whether the HPV vaccine is efficacious in preventing oral HPV infections and related diseases, and (3) determining whether the HPV status of the tumor should be used in clinical decision-making pertaining to treatment. D’Souza et al. [1] used 2 distinct populations and differing study methods to evaluate associations between self-reported sexual behaviors and detection of prevalent oral HPV infection. The oral HPV point prevalence was 2.9% among 210 college-aged men and 4.8% among 332 controls in a hospital-based case-control study. Although these percentages are not statistically different, it is noteworthy that the point prevalence among college-aged men (median age, 19 years) was lower than that in the older hospital-based control group (median age, 57 years); this finding has been observed in previous studies [5, 6]. This finding does not parallel the striking inverse trend of decreasing cervical HPV prevalence with increasing age [7]. Differences in the methods of specimen collection in the study (specifically, the addition of the use of an oropharynx brush in the hospital-based control population, compared with the use of oral rinse and gargle alone by college-aged men) may have accounted for some of this difference, as a result of the improved sensitivity of detection of oral HPV infections in the hospital-based study. In addition, the hospital-based controls may have come from a higher-risk population, and, therefore, findings for this group would not be reflective of the true prevalence among older adults. Similarly, older adults may be more likely to have persistent infection detected, which could also inflate the point prevalence. Alternatively, it may be that the natural history of oral HPV infection actually differs from that of the cervix. This finding highlights the importance of developing and standardizing specimen collection, storage, and testing methods that reliably measure infection with high sensitivity, and it strongly argues for additional large, welldesigned studies to better understand the natural history of oral HPV infection. Despite the use of different study designs and populations, as well as different questionnaire variables assessing exposure, the findings that sexual behaviors and, specifically, oral sex are associated with prevalently detected oral HPV infection are consistent in the 2 populations. In addition, open-mouthed kissing (inquired about in the study of college-aged men only) was significantly associated with oral HPV infection. Even among the men who reported never having had oral sexual contact, more kissing partners significantly increased the risk of oral HPV infection, suggesting the independence of kissing as a risk factor for oral HPV infection. Although the finding that oral HPV may be transmitted through kissing is intriguing, it is based on a small sample size (6 infections in men from the college study and even smaller numbers in the subset of individuals who reported no Received 5 December 2008; accepted 8 December 2008; electronically published 25 March 2009. Potential conflicts of interest: none reported. Financial support: none provided. Reprints or correspondence: Dr. Aimee R. Kreimer, 6120 Executive Blvd., EPS/7084, Rockville, MD 20852 (kreimera@mail.nih.gov). The Journal of Infectious Diseases 2009; 199:1253– 4 This article is in the public domain, and no copyright is claimed. All rights reserved. 0022-1899/2009/19909-0001 DOI: 10.1086/597756 E D I T O R I A L C O M M E N T A R Y