Contraceptive and reproductive risks for cervical dysplasia in Southwestern Hispanic and non-Hispanic white women

Background: Various contraceptive practices and reproductive factors have been associated with cervical neoplasia in case-control studies worldwide. Methods: To investigate contraceptive and reproductive risk factors associated with high-grade cervical dysplasia in southwestern Hispanic and non-Hispanic white women, we carried out a clinic-based case-control study among university-affiliated clinic attendees. Results: Oral contraceptive use ever (odds ratio [OR] = 0.4, 95% confidence interval [CI]: 0.2-0.9) and past diaphragm use (OR = 0.3, 95% CI: 0.1-0.8) were protective for dysplasia in analyses adjusted for age, ethnicity, sexual behaviour, and for cervical papillomavirus (HPV) infection. After further adjustment for Pap smear screening interval, oral contraceptive use ever remained protective for dysplasia. Vaginal deliveries were strongly associated with dysplasia with > 2 vaginal deliveries associated with a 3.9-fold increase in risk after adjustment for age, ethnicity, sexual behaviour, and HPV infection. Using logistic regression models to simultaneously control for effects of multiple factors as potentially related to cervical dysplasia, we found low educational attainment, cervical HPV infection, cigarette smoking, history of any sexually transmitted disease, and having one or more vaginal deliveries to be associated with dysplasia; oral contraceptive use and past diaphragm use also remained protective for high-grade cervical dysplasia in these regression analyses. Conclusions: The data suggest that use of oral contraceptives (ever) and past diaphragm use are protective for high-grade cervical dysplasia among Hispanic and non-Hispanic white women in New Mexico. The clinic-based perspective of this research (versus population-based studies) may help explain some of these findings.