THE NATURAL-HISTORY OF HUMAN-PAPILLOMAVIRUS INFECTION AS MEASURED BY REPEATED DNA TESTING IN ADOLESCENT AND YOUNG-WOMEN

Objectives: The objectives of this study were to describe the early na tural history of human papillomavirus (HPV) infection by examining a c ohort of young women positive for an HPV test and to define within thi s cohort (1) the probability of HPV regression, (2) the risk of having a squamous intraepithelial lesion, and (3) factors that were associat ed with HPV regression. Study design: The study was a cohort analytic design. Ar inception cohort of 618 women positive for HPV participated . HPV testing, cytologic evaluation, and colposcopic evaluation were p erformed at 4-month intervals. HPV testing was characterized for two g roups: low risk (five types rarely associated with cancers) and high r isk (nine types most commonly associated with cancers). Results: Estim ates provided by Kaplan-Meier curves showed that similar to 70% of wom en were found to have HPV regression by 24 months. Women with low-risk HPV type infections were more likely to show HPV regression than were women with highrisk HPV type infections (log rank test p = 0.002). Th e relative risk fbr the development of high-grade squamous intraepithe lial lesion (HSIL) was 14.1 (95% confidence interval: 2.3, 84.5) for w omen with at least three positive tests for high-risk HPV preceding th e development of the HSIL compared with that for women with negative t ests for high-risk HPV. However, 88% of women with persistent positive HPV tests have not had HSIL to date. No factors associated with high- risk HPV type regression were identified except for a negative associa tion with an incident history of vulvar condyloma (relative risk = 0.5 [95% confidence interval: 0.3 to 0.8]). Conclusion: Most young women with a positive HPV test will become negative within a 24-month period . Persistent positive tests with oncogenic HPV types represented a sig nificant risk for the development of HSIL. However, we found that most young women with persistent positive HPV tests did not have cytologic ally perceptible HSIL over a 2-year period. Factors thought to be asso ciated with the development of HSIL were found not to be important in HPV regression.