recent study led by University of Florida researchers found that approximately 11 million men and 3 million women in the U.S. are infected with oral human papillomavirus, or HPV. The study, which was published in Annals of Internal Medicine, also found that men are almost six times more likely to be infected with cancer-causing oral HPV strains. HPV infection can be responsible for several cancers, including cancers in the back of the throat in an area called the oropharynx.

“The rates of oropharyngeal cancer among men have risen more than 300 percent in the past 40 years, making it the most common HPV-related cancer,” said study lead author Ashish A. Deshmukh, Ph.D., M.P.H., an assistant professor in the department of health services research, management and policy in the UF College of Public Health and Health Professions.

To gain a better understanding of oral HPV infection and its concordance with genital HPV infection, the team analyzed data from the National Health and Nutrition Examination Survey 2011-2014, a nationally representative survey conducted by the National Center for Health Statistics that combines survey questions with laboratory testing.

The team found infection with HPV type 16, one of the strains responsible for causing most oropharyngeal cancers, was seven times more common among men than in women. Nearly 2 million men in the United States are infected with HPV 16.

Researchers also identified several demographic and behavioral risk factors. The age group with the highest prevalence of oral HPV infection among men was 50 to 69 years. This group is also experiencing rising rates of oropharyngeal cancer.

The research team found that men and women with same-gender partners had a fourfold higher prevalence of oral HPV infection.

The study is also the first to examine dual oral and genital HPV infection among men. The findings showed that oral HPV infection was five times more common among men with genital HPV infection and concordant oral and genital HPV infection was three times more common among men than women.

Men who had more than 16 lifetime oral sex partners were 10 times more likely to have dual oral and genital HPV infection. Men with a history of other sexually transmitted infections, such as chlamydia or gonorrhea, were three times more likely to have both oral and genital HPV infection.

The study is particularly important because the HPV vaccination rate among boys remains low and most men who are at risk for oropharyngeal cancer are over the vaccine eligibility age, Deshmukh said.

“Studies like ours are critical for guiding the design and development of strategies targeted toward prevention of oropharyngeal cancer among high-risk individuals,” Deshmukh said.