Risk Factors for High-Grade Cervical Intraepithelial Neoplasia in Patients with Atypical Squamous Cells of Undetermined Significance (ASC-US) Papanicolaou Smears

Objective: To determine risk factors of high-grade cervical intraepithelial neoplasia (CIN 2-3) among womenwith atypical squamous cells of undetermined significance (ASC-US) Papanicolaou (Pap) smears.
Methods: Twohundredand sixty-six women with ASC-US Pap tests who underwent a colposcopy with histologic study wereenrolled between August 2008 and June 2010. Patient data including age, education, income, parity, currentpills used, number of vaginal deliveries, number of sexual partners, age at first sexual intercourse, history ofsexually transmitted diseases, history of pelvic inflammatory disease and smoking habits were obtained. Logisticregression analysis was used to evaluate factors associated with CIN 2-3.
Results: CIN was diagnosed in 134 of266 women (50.4%). Ninty-seven of these (72.4%) had CIN 1 and 37 (27.6%) had CIN 2-3. Frequency of thelatter was lower in women who had at least bachelor’s degree graduation as compared to those having less thanprimary school graduation (odds ratio (OR) 0.085, 95% confidence interval (CI) 0.013-0.557). In addition, thosewith a higher income (5,000-20,000 baht per month) had less frequent CIN 2-3 (OR 0.378, 95% CI 0.147-0.970),whereas women who had 3 or more sexual partners were more likely to develop CIN 2-3 (OR 3.181, 95% CI1.316-7.687).
Conclusions: Women with ASC-US Pap smears who had 3 or more sexual partners, low educationand low income were at an increased risk of CIN 2-3. Therefore, this group of patients deserve a high priorityfor immediate colposcopy in order for early detection of high-grade CIN.