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.

Cancer Causes Control. 2010 Nov;21(11):1745-57.
Park Y, Spiegelman D, Hunter DJ, Albanes D, Bergkvist L, Buring JE, Freudenheim JL, Giovannucci E, Goldbohm RA, Harnack L, Kato I, Krogh V, Leitzmann MF, Limburg PJ, Marshall JR, McCullough ML, Miller AB, Rohan TE, Schatzkin A, Shore R, Sieri S, Stampfer
Cancer Causes Control. 2010 Nov;21(11):1745-57.
La somministrazione di polivitaminici (vitamine A-C-E) è significativamente inversamente associato al rischio di cancro del colon.
Vitamina A-C-E/cancro del colon.

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.