Active and Passive Cigarette Smoke Exposure and Cervical lntraepithelial Neoplasia1

This case-control analysis presents odds ratios for active and passive cigarette smoke exposure and cervical intraepithelial neoplasia of levels II and III (CIN II and CIN Ill) while controlling for confounders. From 1987 to 1988, 103 biopsy-conformed incident cases of CIN II or Ill and 268 controls with normal cervical cytology were enrolled. Seventy % of cases were cigarette smokers, while only 30% of controls had ever smoked. The adjusted odds ratio for current cigarette smoking was 3.4 (95% confidence interval, 1.7-7.0). The following confounders were included in logistic regression models: age, race, education, number of sex partners, contraceptive use, sexually transmitted disease history, and Pap smear history. The risk of CIN Il/Ill increased with increasing years of cigarette smoking and with increasing pack-years of exposure. Smoking was associated more strongly with CIN Ill than CIN II. The effect of passive cigarette smoke exposure was explored separately for smokers and nonsmokers and was found not to be consistently associated with CIN Il/Ill when controlling for confounders.