Cofactors With Human Papillomavirus in a Population-Based Study of Vulvar Cancer

Background: Human papillomavirus (HPV) has been previ-ously associated with vulvar cancer. In a population-based study, we examined whether exposure to HPV, cigarette smoking, or herpes simplex virus 2 (HSV2) increases the risk of this cancer. Methods: Incident cases of in situ (n = 400) and invasive (n = 110) squamous cell vulvar cancer diagnosed among women living in the Seattle area from 1980 through 1994 were identified. Serum samples were analyzed for an-tibodies against specific HPV types and HSV2. HPV DNA in tumor tissue was detected by means of the polymerase chain reaction. In most analyses, case subjects were compared with population-based control subjects (n = 1403). Relative risks of developing vulvar cancer were estimated by use of ad-justed odds ratios (ORs) and 95 % confidence intervals (CIs). Results: Increased risks of in situ or invasive vulvar cance