Randomized double-blind trial of beta-carotene and vitamin C in women withminor cervical abnormalities

A double-blind, placebo-controlled, randomized, factorial study using a dai ly oral administration of 30 mg beta-carotene and/or 500 mg Vitamin C was c onducted in 141 women with colposcopically and histologically confirmed min or squamous atypia or cervical intraepithelial neoplasia (CIN) I. Over appr oximately 2 years of follow-up, 43 lesions regressed to normal and 13 progr essed to CIN II. The regression rate was slightly higher, but not significa ntly so, in those randomized to beta-carotene compared to no beta-carotene (hazard ratio = 1.58, 95% CI: 0.86-2.93, P = 0.14) and slightly lower, but not statistically significant, for those randomized to vitamin C compared t o no vitamin C (hazard ratio = 0.65, 95% CI: 0.35-1.21, P = 0.17). In a mod el with no interaction, the progression rate was slightly higher in those r andomized to beta-carotene (hazard ratio = 1.75, 95% CI: 0.57-5.36, P = 0.3 2) and also in those randomized to vitamin C (hazard ratio = 2.40, 95% CI: 0.74-7.80, P = 0.13). Neither of these were statistically significant. Howe ver, there was some evidence of an interaction effect of the two compounds on the progression rate (P = 0.052), with seven of the progressed lesions o ccurring in those randomized to both Vitamins compared to a total of six in the three other groups. The currently available evidence from this and oth er trials suggests that high doses of these compounds are unlikely to incre ase the regression or decrease the progression of minor atypia and CIN I.