Jan. 11 (UPI) -- Having more than 10 oral sex over a lifetime partners quadruples a person's risk for human papillomavirus-related mouth and throat cancer, a study published Monday by the journal Cancer found.
In addition, having oral sex at a younger age, and with more partners, also increases the risk for cancers of the mouth and throat caused by human papillomavirus, or HPV, the data showed.
"Our research helps patients and physicians answer the question of, 'Why did I develop HPV-related ... cancer," study co-author Dr. Virginia Drake told UPI.
"Risk of infection is not solely related to number of lifetime oral sex partners, as timing of oral sex and type of partner also play a role," said Drake, a head and neck surgeon at Johns Hopkins Hospital in Baltimore.
Nationally, just over 7% of all adults ages 18 to 69 have HPV, according to the U.S. Centers for Disease Control and Prevention.
Each year, about 45,000 people -- 55% of them women -- are diagnosed with HPV-related cancers, the agency estimates.
HPV can infect the mouth and throat, leading to the growth of tumors in these areas, although this remains relatively rare, according to the Johns Hopkins researchers.
For this study, Drake and her colleagues surveyed 163 adults with HPV-related mouth and throat cancers, and 345 without these diseases, on their sexual behaviors.
Participants with more than 10 oral sex partners were 4.3 times as likely to develop HPV-related cancers, the data showed.
Having oral sex as an adolescent or teen raised a person's risk for HPV-related cancers by 80%, the researchers said.
Starting younger and having more partners raised the risk for these diseases by 180%, according to the researchers.
People who had older sexual partners when they were young and those with partners who had extramarital sex were up to 70% more likely to have HPV-related cancers, the researchers said.
"People with HPV-associated ... cancer have a wide spectrum of sexual histories," Drake said.
"As with all STDs, having new partners introduces some risk for infection, but most people who become infected clear the infection without developing cancer," she said.