A nested case-control study of dietary factors and the risk of incident cytological abnormalities of the cervix

Nutr Cancer. 1998;30(2):130-6. doi: 10.1080/01635589809514652.

Abstract

Several earlier case-control studies reported inverse associations of cervical squamous intraepithelial lesions (SIL) with high dietary or biomarker levels of carotenoids, folate, and vitamins C and E. However, most studies did not measure the primary causal factor, cancer-associated genital human papillomaviruses (HPV), now detected by sensitive viral DNA tests. This nested case-control study assessed whether high dietary intakes of these nutrients, plus zinc and vitamin A, reduced SIL risk in cancer-associated HPV DNA-positive women. Using a 60-item food-frequency questionnaire, nutrient estimates were obtained for 33 incident cases with high-grade lesions, 121 with low-grade lesions, 97 with equivocal SIL, and 806 cytologically normal controls sampled from a large prospective cohort study. Baseline cervicovaginal lavages were tested for HPV DNA by the polymerase chain reaction. Among DNA-positive cases (n = 68) and controls (n = 69), age-adjusted odds ratios (ORs) of SIL in the highest vs. the lowest nutrient quartiles were 1.4 [95% confidence interval (CI) = 0.5-4.2] for vitamin A, 0.6 (CI = 0.2-2.0) for beta-carotene, 1.3 (CI = 0.4-3.6) for vitamin C, 1.0 (CI = 0.4-3.6) for vitamin E, 0.7 (CI = 0.3-2.1) for folate, and 0.8 (CI = 0.3-2.2) for zinc. ORs in HPV DNA-negative women approximated 1.0, with the exception of vitamin E (OR = 0.5, CI = 0.3-0.9). These results do not support a protective role for the above nutrients against low-grade or equivocal SIL, which constituted the majority of diagnoses in this study.

MeSH terms

  • Adult
  • Ascorbic Acid / administration & dosage
  • Carotenoids / administration & dosage
  • Case-Control Studies
  • Cervical Intraepithelial Neoplasia / prevention & control*
  • Cervical Intraepithelial Neoplasia / virology*
  • Cervix Uteri / virology
  • Cohort Studies
  • DNA, Viral / analysis*
  • Diet*
  • Female
  • Folic Acid / administration & dosage
  • Humans
  • Papillomaviridae / genetics*
  • Papillomavirus Infections
  • Polymerase Chain Reaction
  • Prospective Studies
  • Risk Factors
  • Therapeutic Irrigation
  • Tumor Virus Infections
  • Vitamin E / administration & dosage
  • Zinc / administration & dosage

Substances

  • DNA, Viral
  • Vitamin E
  • Carotenoids
  • Folic Acid
  • Zinc
  • Ascorbic Acid