*Statistical Analysis*

Categorical patients' characteristics at diagnosis were summarized by counts and percent, age by mean and standard deviation and cross-tabulated by VAIN grade. Between VAIN grade groups, comparisons were done by using Fisher's exact test for categorical variables and the F-test for age (one-way analysis of variance). Lesion type and vascularity were significantly associated with colposcopic grade and then entered two separated multivariate logistic regression analyses in order to estimate their association with VAIN grade as risk factors. Results are presented as Odds Ratios (OR) with 95% Confidence Intervals (CI). All tests were two-tailed and considered significant at the 5% level. All analyses were done using SAS 9.4 (Cary, NC, USA).
