ObjectiveTo examine demographic and behavioral factors related to perineal application of powders.MethodsControls from three case-control studies (N= 1206) were asked identical questions about the use of genital powders by direct perineal application. The relationship of perineal powder application with demographic factors, reproductive factors, body mass index (BMI), douching, and alcohol and tobacco use was assessed. Data were analyzed by multiple logistic regression.ResultsWomen who douched (prevalence odds ratio [prevalence OR] 2.0, 95% confidence interval [CI] 1.0, 3.9), drank alcohol (prevalence OR 1.8, 95% CI 1.2, 2.8), smoked cigarettes (prevalence OR 1.3, 95% CI 1.0, 1.8), or were in the highest BMI quartile were more likely to engage in perineal use of powder (prevalence OR 1.6, 95% CI 1.1, 2.6). There appeared to be a close response relationship between the number of perineal applications of powder and BMI (P< .002).ConclusionBody mass index might confound the relationship between perineal powder application and the development of ovarian cancer. Other factors, such as alcohol and tobacco use and douching, are related to perineal use of powder and may represent similar behavioral characteristics.