HPV co-factors related to the development of cervical cancer: results froma population-based study in Costa Rica

We examined factors associated with high-grade squamous intraepithelial les ions (HSIL) and cervical cancer among human papillomavirus (HPV)-infected w omen in a prevalent case-control study conducted within a population-based cohort of 10 077 women in Costa Rica. We compared 146 women with HPV-positi ve HSIL or cancer (HSIL/CA) against 843 HPV-positive women without evidence of HSIL/CA. Subjects completed a risk factor questionnaire. We evaluated t he associations between exposures and HSIL/CA among women positive for any HPV and restricted to those positive for high-risk HPV types. Risk of HSIL/ CA increased with increasing number of live births (P-trend = 0.04). Women who smoked 6+ cigarettes/day had a RR for HSIL/CA of 2.7 (95% CI = 1.1-6.7) compared to non-smokers. Current use of barrier contraceptives was associa ted with a reduction in risk of HSIL/CA (RR = 0.39; 95% CI = 0.16-0.96). Se xual behaviour and a self-reported history of sexually transmitted diseases (STDs) other than HPV were not associated with HSIL/CA. Oral contraceptive use was associated with HSIL/CA among women with <3 pregnancies. Effects w ere similar in analysis restricted to women positive for high-risk HPV type s. Among women positive for high-risk HPV types, 44% of HSIL/CA could be at tributed to multiparity (<greater than or equal to>3 pregnancies) and/or sm oking. Among HPV-positive women, multiparity and smoking are risk factors f or HSIL/CA. Oral contraceptive use may be associated with HSIL/CA in subgro ups of women. (C) 2001 Cancer Research Campaign.