Cervical dysplasia: association with sexual behavior, smoking, and oral contraceptive use?

Information on possible risk factors of cervical dysplasia, including indices of sexual behavior, smoking habits, and the use of oral contraceptives was obtained from a case-control study in Ontario in which 250 cases of histologically proved cervical dysplasia and 500 age-matched neighborhood controls were interviewed. Initial analysis showed an increased risk associated with more than one sexual partner, an early age at first intercourse, current smoking, the use and duration of use of oral contraceptives, and education. However, the increased risk of use and duration of use of oral contraceptives and education was reduced after adjustment for indices of sexual behavior and smoking. This finding does not confirm previously reported large adverse effects of pill use. The relationship between smoking and cervical dysplasia might be explained by some agent in cigarette smoke which depresses the immune mechanism, thus permitting a sexually transmitted agent to result in abnormal cellular development that leads to the onset of cervical dysplasia.