Smoking and cervical intraepithelial neoplasia: nicotine and cotinine in serum and cervical mucus in smokers and nonsmokers.

A blood sample before treatment was taken from 35 women with cervical intraepithelial neoplasia. Levels of nicotine and cotinine were analyzed by radioimmunoassay. Both cotinine and, especially, nicotine were shown to be strongly concentrated in cervical mucus compared with serum levels. These findings confirm the association shown in epidemiologic studies of smoking and cervical neoplasia. It cannot be concluded that smoking is a genuine cause of cervical neoplasia. However, the results support the concept that smoking is a true risk factor in cervical neoplasia.