Risk Factors for Cervical Intraepithelial Neoplasia in Southwestern American Indian Women

The authors assessed risk factors for cervical intraepithelial neoplasia (CIN) among southwestern American Indian women using case-control methods. Cases were New Mexico American Indian women with biopsy-proven grade I (n = 190), grade II (n = 70), or grade III (n = 42) cervical lesions diagnosed between November 1994 and October 1997. Controls were American Indian women from the same Indian Health Service clinics with normal cervical epithelium (n = 326). All subjects underwent interviews and laboratory evaluations. Interviews focused on history of sexually transmitted diseases, sexual behavior, and cigarette smoking. Laboratory assays included polymerase chain reaction-based tests for cervical human papillomavirus infection, tests for gonorrhea and chlamydia, wet mounts, and serologic assays for antibodies to Treponema pallidum, herpes simplex virus, and hepatitis B and C viruses. In multiple logistic regression analysis, the strongest risk factors for CIN II/III among American Indian women were human papillomavirus type 16 infection (adjusted odds ratio (OR) = 7.6; 95% confidence interval (CI): 2.4, 23.2), any human papillomavirus infection (OR = 5.8; 95% CI: 3.3, 10.0), low income (OR = 3.3; 95% CI: 1.7, 6.2), and history of any sexually transmitted disease (OR = 2.0; 95% CI: 1.1, 3.5). Unlike previous research, this study found no strong associations between CIN and sexual activity or cigarette smoking.