Intakes of vitamins A, C, and E and use of multiple vitamin supplements and risk of colon cancer: a pooled analysis of prospective cohort studies.

Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA.
Cancer Causes and Control (Impact Factor: 2.96). 11/2010; 21(11):1745-57. DOI: 10.1007/s10552-010-9549-y
Source: PubMed

ABSTRACT To evaluate the associations between intakes of vitamins A, C, and E and risk of colon cancer.
Using the primary data from 13 cohort studies, we estimated study- and sex-specific relative risks (RR) with Cox proportional hazards models and subsequently pooled RRs using a random effects model.
Among 676,141 men and women, 5,454 colon cancer cases were identified (7-20 years of follow-up across studies). Vitamin A, C, and E intakes from food only were not associated with colon cancer risk. For intakes from food and supplements (total), the pooled multivariate RRs (95% CI) were 0.88 (0.76-1.02, >4,000 vs. ≤ 1,000 μg/day) for vitamin A, 0.81 (0.71-0.92, >600 vs. ≤ 100 mg/day) for vitamin C, and 0.78 (0.66-0.92, > 200 vs. ≤ 6 mg/day) for vitamin E. Adjustment for total folate intake attenuated these associations, but the inverse associations with vitamins C and E remained significant. Multivitamin use was significantly inversely associated with colon cancer risk (RR = 0.88, 95% CI: 0.81-0.96).
Modest inverse associations with vitamin C and E intakes may be due to high correlations with folate intake, which had a similar inverse association with colon cancer. An inverse association with multivitamin use, a major source of folate and other vitamins, deserves further study.

Download full-text


Available from: Alicja Wolk, Jul 07, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: There are more than 4000 natural and synthetic molecules structurally and/or functionally related to vitamin A. Retinoids are a class of these compounds that are structurally associated to vitamin A. The retinoids have a wide spectrum of functions. Retinoic acid, which is the active metabolite of retinol, regulates a wide range of biological processes including development, differentiation, proliferation and apoptosis. It suppresses carcinogenesis in tumorigenic animal models for the skin, oral, lung, breast, bladder, ovarian and prostate. It is important how major retinoids may act in cancer treatment or prevention. The reports have indicated that lower levels of vitamin A in humans may be associated with relative type 1 cytokine dominance and a higher proportion of NK cells. In addition, very low vitamin A levels would be undesirable explaining the essential role of vitamin A in epithelial and general cell maturation and function. However, the cytokine shifts associated with moderately low levels of vitamin A may be in some ways beneficial in an environment where HIV infection, M. tuberculosis infection, or other type 1 infections are highly prevalent and/or when acquired immunity is cooperated. In this review, we intend to describe the biochemical and immunological functions of retinoids against cancer.
    International immunopharmacology 11/2013; 18(1). DOI:10.1016/j.intimp.2013.10.027 · 2.71 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Super-resolution near-field structure (Super-RENS) was introduced by Tominaga et al. (1998) to perform the task of near-field recording in a more feasible way. Super-RENS has the advantages of simpler recording head design, less mechanic damage, and higher recording speed. Our previous research has shown that the collective effects of the localized surface plasmon and the heterogeneous material structure are responsible for the unusual optical property of the Super-RENS. To further explore the nonlinear near-field optical property of the Super-RENS, we studied direct near-field optical images and two-dimensional finite-difference time-domain (FDTD) simulations of the AgO<sub>x</sub> super-RENS. Our results provide a direct connection between the surface plasmon effects of silver nanoparticles and nonlinear near-field optical property observed in experiments.
    Optical Memory and Optical Data Storage Topical Meeting, 2002. International Symposium on; 02/2002
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Studies of folate intake and colorectal cancer risk have been inconsistent. We examined the relation with colon cancer risk in a series of 13 prospective studies. Study- and sex-specific relative risks (RRs) were estimated from the primary data using Cox proportional hazards models and then pooled using a random-effects model. Among 725,134 participants, 5,720 incident colon cancers were diagnosed during follow-up. The pooled multivariate RRs (95% confidence interval [CI]) comparing the highest vs. lowest quintile of intake were 0.92 (95% CI 0.84-1.00, p-value, test for between-studies heterogeneity = 0.85) for dietary folate and 0.85 (95% CI 0.77-0.95, p-value, test for between-studies heterogeneity = 0.42) for total folate. Results for total folate intake were similar in analyses using absolute intake cutpoints (pooled multivariate RR = 0.87, 95% CI 0.78-0.98, comparing ≥ 560 mcg/days vs. <240 mcg/days, p-value, test for trend = 0.009). When analyzed as a continuous variable, a 2% risk reduction (95% CI 0-3%) was estimated for every 100 μg/day increase in total folate intake. These data support the hypothesis that higher folate intake is modestly associated with reduced risk of colon cancer.
    Cancer Causes and Control 11/2010; 21(11):1919-30. DOI:10.1007/s10552-010-9620-8 · 2.96 Impact Factor