Smokers aren't only at high risk of lung cancer. They are also more prone to a certain type of sexually transmitted infection, says a new study.

Research shows that participants who reported tobacco use and showed higher biomarker levels of exposure to tobacco were found to have a higher incidence of the oral human papillomavirus type 16 or HPV-16, a sexually transmitted infection. HPV-16 is believed to be responsible for the rising incidence of oropharyngeal squamous cell cancers in the U.S.

Carole Fakhry and colleagues from the Johns Hopkins University School of Medicine, Baltimore made use of figures from the National Health and Nutrition Examination Survey (NHANES), which is said to be the U.S. population's probability sample. Involved were 6,887 participants from the NHANES. Of these, 2,012 or 28.6 percent are tobacco users at present; 63 or one percent of them were detected to have oral HPV-16.

The researchers investigated the relationship between HPV-16 and tobacco exposure. They also observed the association between the prevalence of oral HPV and the self-reported number of cigarettes the participants smoked per day.

Participants aged 14 to 69 years were qualified for DNA testing of the sexually transmitted infection. Computer-assisted interviews were also used to determine the use of tobacco and sexual activity of the subjects.

The researchers found that tobacco smokers were more likely to be male and younger, less educated and with a higher number of lifetime partners in oral sexual activities than non-smokers.

"Self-reported and biological measures of tobacco exposure as well as oral sexual behavior were significantly associated with prevalent oral HPV-16 infection," researchers conclude. Their findings emphasize the need for evaluating the role of tobacco in the spread of oral sexual infection and its progression to malignancy.

The researchers say 80 percent of cancers in the back of the throat are linked to HPV-16, which in turn gets transmitted through oral sex. For the past 20 years, such cancer swelled by 225 percent in the U.S. alone.

The American Cancer Society estimates that around 37,000 Americans, predominantly men, will have throat or mouth cancer this year, of which 7,300 will die from it, according to WebMD.

The study "Tobacco Use and Oral HPV-16 Infection" is published in the Journal of the American Medical Association on Oct. 8