The role of vitamins in the etiology of cervical neoplasia: an epidemiological review.

Diet may act as a cofactor in the development of cancer of the cervix. A consistent correlation exists between low tissue concentrations, low serum level, and low intake of vitamin A, beta-carotene, vitamin C, or folic acid and an increased prevalence of cervical neoplasia. A moderate effect is seen in clinical trials with vitamin treatment of cervical intraepithelial neoplasias. The studies reviewed here were not consistent especially in the choice of controls and methods for the assessment of dietary and confounding factors. Proper morphologic identification of cervical intraepithelial neoplasia was not always achieved. Longitudinal and prospective cohort studies using more reliable methods for diet monitoring may be valuable for future research in this field.