Descriptive evidence that risk profiles for cervical intraepithelial neoplasia 1, 2, and 3 are unique.

OBJECTIVE This study aimed to estimate if risk factor profiles for histologically confirmed cervical intraepithelial neoplasia (CIN) 2 lesions differ from those for CIN 1 or 3. METHODS A total of 2,055 women positive for high-risk human papillomavirus, with a minimum of five cervical biopsies, were enrolled in the Shanxi Province Cervical Cancer Screening Study II. We evaluated risk factor profiles for CIN 2 in comparison with CIN 1 and 3. Polytomous logistic regression was used to generate odds ratios and corresponding 95% confidence intervals and to test for differences in odds ratios across histologic grades. RESULTS The risk for CIN 3 associated with three or more pregnancies and sexual intercourse within 4 months of childbirth was higher than that for CIN 2 (P(difference) = 0.02 and 0.0007, respectively). Significant differences in the associations of age groups with CIN 1 and 2 were observed, such that there were positive associations with CIN 2 but none for CIN 1. There was no difference in the association of number of sexual partners or reported number of abortions between CIN 1 and 2 or between CIN 3 and 2. CONCLUSIONS In our study, the patterns of risk factor profiles for CIN 1, 2, and 3 were unique. Conventional grouping of CIN 2 with 3 for analysis of risk factors may need revisiting.