title: The effect of intrauterine devices on acquisition and clearance of human papillomavirus.
abstract: BACKGROUND
  Previous studies have shown a decrease in cervical cancer associated with intrauterine device use. It has been hypothesized that intrauterine device use may alter the natural history of human papillomavirus infections, preempting development of precancerous lesions of the cervix and cervical cancer, but the effect of intrauterine devices on the natural history of human papillomavirus infection and subsequent development of cervical cancer is poorly understood.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the association between intrauterine device use and cervical high-risk human papillomavirus acquisition and clearance.
  
  
  METHODS
  This is a prospective cohort study conducted from October 2000 through June 2014 among 676 sexually active young women and girls enrolled from family planning clinics in San Francisco, CA. Data were analyzed using a Cox proportional hazards model, including time-varying indicators of intrauterine device use, and adjusting for fixed and time-dependent predictor variables.
  
  
  RESULTS
  A total of 85 women used an intrauterine device at some time during follow-up. Among 14,513 study visits, women reported intrauterine device use at 505 visits. After adjusting for potential behavioral confounders, there was no association between intrauterine device use and human papillomavirus acquisition (hazard ratio, 0.50; 95% confidence interval, 0.20-1.23; P = .13) or clearance of human papillomavirus infection (hazard ratio, 1.44; 95% confidence interval, 0.76-2.72; P = .26).
  
  
  CONCLUSIONS
  Current intrauterine device use is not associated with acquisition or persistence of human papillomavirus infection. Intrauterine device use is safe among women and girls with human papillomavirus infections and at risk for human papillomavirus acquisition. Intrauterine device use may play a role further downstream in the natural history of cervical cancer by inhibiting the development of precancerous lesions of the cervix in human papillomavirus-infected women, or enhancing clearance of established precancerous lesions.
authors.affiliation: Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, CA; Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA. Electronic address: sarah.averbach@ucsf.edu.
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Averbach
authors.affiliation: Department of Pediatrics, University of California, San Francisco, San Francisco, CA.
authors.forename: Yifei
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, CA.
authors.forename: Karen
authors.initials: K
authors.lastname: Smith-McCune
authors.affiliation: Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Shiboski
authors.affiliation: Department of Pediatrics, University of California, Los Angeles, Los Angeles, CA.
authors.forename: Anna B
authors.initials: AB
authors.lastname: Moscicki
mesh_terms: D000293:Adolescent; D002584:Cervix Uteri / Q000821:virology; D015331:Cohort Studies; D005260:Female; D015438:Health Behavior; D006801:Humans; D007434:Intrauterine Devices; D027383:Papillomaviridae; D030361:Papillomavirus Infections / Q000453:epidemiology* / Q000821:virology*; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012495:San Francisco; D055815:Young Adult
keywords: cervical cancer; contraception; dysplasia; human papillomavirus; intrauterine device; sexually transmitted infection