Article published by the American Dental Association on August 23, 2013
Dental patients may ask about a new University of Texas-Houston study 1 that is reportedly the first to identify poor oral health as an independent risk factor for oral human papillomavirus (HPV) infection, which is associated with a variety of oral lesions and a subset of oral and oropharyngeal cancers. The study, published online in the journal Cancer Prevention Research, was widely publicized by the New York Times, Time Magazine and other news agencies.
The study looked at data from over 3,400 adults who participated in the 2009-2010 National Health and Nutrition Examination Survey (NHANES), and who also had data available on oral health measures and oral HPV infection. The large number of subjects in this study provides strong statistical power to detect differences between variables.
Using this NHANES dataset, the researchers found a higher prevalence of oral HPV infection among individuals with poor oral health, including a significantly elevated risk of oral HPV in adults with self-reports of poor-to-fair oral health or possible gum disease. From the study sample, 7.5 percent of the NHANES participants also tested positive for oral HPV infection.
After multivariable analysis of the NHANES data, the research team determined that self-rated poor oral health was an independent risk factor for oral HPV infection regardless of the study participants’ smoking or oral sex practices, two known risk factors for head and neck cancer. As reported in previous studies, the UT-Houston researchers also found that men, users of alcohol or marijuana, and individuals with more oral sex partners over time had a higher prevalence of oral HPV infection.
Exposure to HPV occurs commonly through sexual contact, and papillomaviruses can induce a wide range of cutaneous or mucosal epithelial lesions, mostly benign hyperplasias such as papillomas (warts). Over 100 HPV subtypes are known to infect mucosal surfaces in various sites of the body, including the skin, anogenital tract and oral cavity.
The study authors assert that individuals with poor oral health could have ulcerations, chronic inflammation or other disruptions of the oral mucosa, which “may increase susceptibility to and infectiousness of HPV.” Given HPV’s proclivity to infect epithelial basal cells in the oral cavity and other mucosal surfaces, it is indeed suggestive that individuals with poor oral health could have a higher susceptibility to oral infection with HPV, which could gain access to the oral cavity through epithelial wounds or other oral lesions.
The University of Texas-Houston researchers cite several limitations of their study, including the use of self-reported oral health data from NHANES, which could not be used to evaluate temporal aspects regarding the occurrence of HPV infection or the frequency of oral hygiene care (e.g., brushing, flossing). Study participants with poor oral hygiene habits may also have had poor general health habits that contributed to oral HPV infection.
In addition, the study findings only show an association, and do not prove cause and effect. Individuals under age 30 and a large proportion of unmarried individuals were also excluded from the study due to data availability. Although this study is suggestive, considerable research still needs to be done to elucidate the association between oral health, oral hygiene habits and HPV infection in the oral cavity.
The incidence of HPV-associated oropharyngeal cancer is increasing, particularly among men, who accounted for over 10,000 HPV-positive head and neck cancers in 2009. HPV-associated oropharyngeal cancers typically develop near the base of the tongue and in the tonsils, and are often difficult to detect in their earliest stages.
Oral health professionals should remain aware of the increasing incidence of HPV-associated oropharyngeal cancer, and promote optimal oral health and hygiene to minimize the risk of oral disease or infection. The ADA strongly supports optimal oral health for all individuals, and will continue to monitor emerging research on HPV-associated oropharyngeal cancer to reduce its incidence.
1. Bui TC, Markham CM, Ross MW, Dolan Mullen P. Examining the association between oral health and oral HPV infection. Cancer Prev Res. Published online first August 21, 2013; doi:10.1158/1940-6207.