Persistence of high-risk human papillomavirus infection in a population-based cohort of Danish women.

Persisting human papillomavirus (HPV) infection is a critical step in cervical carcinogenesis. This study was conducted to determine the type-specific HPV persistence and risk factors for persistence of high-risk HPV infections in a large cohort of Danish women. The study was based on a population-based prospective cohort study of women aged 20-29 years. Participants were interviewed and underwent two gynecological examinations 2 years apart. Women with Hybrid Capture 2 results at enrolment and a follow-up visit were included in the analysis (n = 7,418). Persistence was defined as positivity for the same high-risk HPV type at both examinations. Overall, 4.2% of the women had persistent HPV infection, accounting for 26.9% of the initially HPV-positive women. HPV 16, HPV 58, and HPV 31, all from species group alpha 9, were the most persistent types; however, other high-risk HPV types that are detected rarely in cancer cases were also likely to persist. The number of high-risk HPV types and detection of HPV 16 infection at baseline and ever use of oral contraceptives increased the risk for persistence. The risk factor analyses also showed that use of an intrauterine device decreased the risk for persistent high-risk HPV infection among women with one high-risk HPV type at baseline. No association was found with viral load or smoking. In conclusion, persistent high-risk HPV infection, especially HPV 16 persistence, was common among women positive for high-risk HPV.