title: Risk Factors for Oral Human Papillomavirus Infection in Healthy Individuals: A Systematic Review and Meta-Analysis.
abstract: BACKGROUND
  Oral human papillomavirus (HPV) infection is associated with oral cancer development. However, few epidemiologic investigations have focused on oral HPV prevalence in healthy individuals. The objective of this study was to provide updated information regarding oral HPV prevalence in patients without oral cancer worldwide.
  
  
  METHODS
  We systematically reviewed 29 studies reporting the prevalence of oral HPV infection that included 22,756 subjects (10,124 males, 12,623 females, and nine unknown gender; age range 2 - 89 years) and were published from January 2012 to June 2015.
  
  
  RESULTS
  The prevalence of overall HPV, low-risk type HPV, high-risk type HPV, and HPV16 in the reported cases was 5.5%, 2.2%, 2.7%, and 1.0%, respectively. The prevalence of overall HPV was considerably higher in males who had sex with males (12.2%) as compared to heterosexual males (4.7%) and females (2.9%). A meta-analysis was performed to elucidate significant risk factors for oral HPV infection, which revealed a significant statistical association for oral sex and smoking with oral HPV infection (odds ratio (OR): 1.90, 95% confidence interval (CI): 1.51 - 2.39, P < 0.0001; OR: 2.13, 95% CI: 1.32 - 3.43, P = 0.002).
  
  
  CONCLUSIONS
  Our findings suggest that sexual behavior and smoking are importantly related to oral HPV infection in healthy individuals.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Shigeishi
authors.affiliation: Department of Public Oral Health, Institute of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Sugiyama
keywords: HPV; Infection; Meta-analysis; Risk factors