Human papillomavirus (HPV), the most common sexually transmitted infection in the nation, is associated with an increased risk of cardiovascular disease, a new study found. HPV is already associated with cervical cancer and a vaccine for it is the subject of controversy.

Researchers found that women infected with HPV are two to three times as likely as uninfected women to have had a heart attack or stroke, according to report published in The Journal of the American College of Cardiology.

The study looked at why some 20 percent of patients with heart disease do not also have typical risk factors such as high cholesterol or high blood pressure, says Dr. Kenichi Fujise, cardiologist at the University of Texas and the study's senior author. The results were surprising.

"I was thinking maybe there would be just a weak link or no link (to HPV), but this is a strong link," Fujise said.

HPV appears to suppress an important gene, p53, which may help prevent artery disease.

It is estimated that half of all sexually active men and women have been infected with HPV, and that 80 percent of women get it by the age of 50. Only some strains of HPV cause cancer, however, and in most people, the immune systems fights off the virus. Vaccines can prevent HPV in those not already infected and are currently recommended for young people before they become sexually active.