A study published in JAMA reveals that among men and women between the ages 14 to 69 years in the U.S., the overall prevalence of oral human papillomavirus(HPV) infection is around 7%. In addition, the researchers found that the prevalence of HPV is higher among men than women.
The study is being published early online in order to accompany its presentation at the Multidisciplinary Head and Neck Cancer Symposium.
The researchers explain:
"Oral HPV infection is the cause of a subset of oropharyngeal [relating to the mouth and pharynx] squamous cell carcinomas (OSCC). Human papillomavirus - positive OSCC are associated with sexual behavior in contrast to HPV-negative OSCC that are associated with chronic tobacco and alcohol use.
At least 90 percent of HPV-positive OSCC are caused by high-risk (or oncogenic) HPV type 16 (HPV-16), and oral infection confers an approximate 50-fold increase in risk for HPV-positive OSCC. The incidence of OSCC has significantly increased over the last 3 decades in several countries, and HPV has been directly implicated as the underlying cause.
Although oral HPV infection is the cause of a cancer that is increasing in incidence in the United States, little is known regarding the epidemiology of infection."
In order to analyze the prevalence of oral HPV in the U.S., Maura L. Gillison, M.D., Ph.D., of the Ohio State University Comprehensive Cancer Center, Columbus, and colleagues examined data from a cross-sectional study as part of the National Health and Nutrition Examination Survey (NHANES) 2009-2010, a statistically representative sample of the U.S. population.
The 5,579 participants, aged between 14 to 69 years old, provided a 30-second oral rinse and gargle with mouthwash. In order to detect HPV types, the researchers assessed DNA purified from oral exfoliated cells through testing methods.
Results revealed that the most prevalent HPV type detected was HPV-16 (1.0%) and the overall prevalence of oral HPV infection was 6.9%. The researchers discovered peaks in the prevalence of oral HPV infection in different age ranges:
- The first peak was found among participants aged between 30 to 34 years old (7.3%).
- The second among participants aged between 60 to 64 years old (11.4%).
The overall prevalence of oral HPV infection was considerably lower among women (3.6%) than men (10.1%). The prevalence was also higher among cigarette smokers, former and current marijuana users, and heavy alcohol drinkers.
In addition, the team discovered that the prevalence of oral HPV was linked to numerous measures of sexual behavior. They found that the prevalence was higher among participants who reported ever having sex (7.5%) than those who did not (0.9%).
Lifetime or recent number of sexual partners for any kind of sex, oral or vaginal, increased the prevalence of HPV.
In analysis inclusive of people aged 14 to 69 years, the researchers found that sex, lifetime number of sexual partners, as well as current number of cigarettes smoked per day, were factors independently linked to prevalent oral HPV.
According to the researchers, their data provide evidence that oral HPV infection is primarily sexually transmitted. "Taken together, these data indicate that transmission by casual, nonsexual contact is likely to be unusual." The researchers explain:
"Our results have important research as well as public health implications. Natural history studies of cervical HPV infection were essential for the development of public health interventions, such as HPV vaccination to prevent and HPV detection to screen for cervical cancer. Natural history studies of oral HPV infection are therefore necessary to understand the effects of age, sex, and modifiable risk factors (e.g., smoking and sexual behavior) on the incidence and duration of oral HPV infection."
"...vaccine efficacy against oral HPV infection is unknown, and therefore vaccination cannot currently be recommended for the primary prevention of oropharyngeal cancer. Given an analysis of U.S. cancer registry data recently projected that the number of HPV-positive oropharyngeal cancers diagnosed each year will surpass that of invasive cervical cancers by the year 2020, perhaps such vaccine trials are warranted. Such trials could inform ongoing discussions regarding the benefits of HPV vaccination for males, given the higher prevalence of oral HPV infection demonstrated here as well as higher incidence of HPV-positive OSCC among men."
In an associated report, Hans P. Schlecht, M.D., M.M.Sc., of the Drexel University College of Medicine, Philadelphia, explains:
"Future research will need to identify the natural history of HPV-related oropharyngeal dysplastic lesions and evaluate potential screening methods to detect oropharyngeal dysplasia prior to invasion. Successful screening measures such as a Papanicolaou test, HPV polymerase chain reaction testing, or both may be daunting to achieve, but there is meaningful hope that prevention efforts will ameliorate the effects of HPV-related oropharyngeal cancer."