The effect of beta-carotene on the regression and progression of cervical dysplasia: A clinical experiment

Henrica C.W. dE Vet, Paul G. Knipschild, Dirk Willebrand, Hubert J.A. Schouten, Ferd Sturmans

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In order to gain insight into the causality of the relation between β-carotene and cancer, we performed a randomized placebo-controlled trial in which the effect of β-carotene on the regression and progression rates of cervical dysplasia were examined. The experimental group (n = 137) received a supplemental dose of 10 mg of β-carotene daily for 3 months. The control group (n = 141) received placebo capsules. As the outcome parameter, two definitions of regression and progression were used, which were based on the degree of dysplasia before and after the medication period. The number of patients who showed progression was too small to allow conclusions. No effect of β-carotene on the regression percentages was observed: OR = 0.68 (95% CI: 0.28-1.60) using the broad definition; and OR = 1.22 (95% CI: 0.43-3.41) with the strict definition. A secondary analysis, in which the effect of the total intake of β-carotene (diet + medication) on the regression percentages of cervical dysplasia was studied, did not show a positive effect either. The paper discusses to what extent issues in the study design may have masked a potential effect and how our results affect the evidence for a causal relation between β-carotene and cancer.

Original languageEnglish
Pages (from-to)273-283
Number of pages11
JournalJournal of Clinical Epidemiology
Issue number3
Publication statusPublished - 1 Jan 1991


  • Carotene
  • Cervical dysplasia
  • Clinical trials
  • Neoplasms

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