The effect of alpha-tocopherol and bêta-carotene supplementation on colorectal adenomas in middle-aged male smokers.
Epidemiological and experimental studies have indicated that dietary factors such as vitamin C, vitamin E, and bêta-carotene are associated with the risk of colorectal cancer.
This study was carried out within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC Study), whose participants were randomly assigned to four supplementation groups :
(a) alpha-tocopherol (AT), 50 mg/day ;
(b) bêta-carotene (BC), 20 mg/day ;
(c) both AT and BC ;
and (d) placebo.
We included the 15,538 ATBC Study participants who had been randomized within the areas of three major cities in southern Finland.
Cases of colorectal adenoma (n=146) were identified by the pathology laboratories in the study areas, and these participants'medical records were collected and reviewed. alpha-tocopherol supplementation increased the risk for adenomas (relative risk, 1.66 ; 95% confidence interval, 1.19-2.32), whereas bêta-carotene supplementation had no effect on the risk (relative risk, 0.98 ; 95% confidence interval, 0.71-1.35).
Slightly more prediagnosis rectal bleeding and intestinal pain occurred in those adenoma cases who received alpha-tocopherol supplements than in those who did not.
Thus, some bias may have resulted, with alpha-tocopherol supplementation leading to more colonoscopies and, thus, to an increased detection of incident polyps in this group.
This is further supported by the trial finding that alpha-tocopherol supplementation did not increase the risk of colorectal cancer.
Mots-clés Pascal : Tumeur maligne, Côlon, Rectum, Tocophérol, Carotène, Supplémentation, Incidence, Tabagisme, Epidémiologie, Facteur risque, Prévention, Activité biologique, Adulte, Homme, Mâle, Etude en condition contrôlée, Finlande, Europe, Appareil digestif pathologie, Intestin pathologie, Côlon pathologie, Rectum pathologie
Mots-clés Pascal anglais : Malignant tumor, Colon, Rectum, Tocopherol, Carotene, Supplementation, Incidence, Tobacco smoking, Epidemiology, Risk factor, Prevention, Biological activity, Adult, Human, Male, Controlled environment study, Finland, Europe, Digestive diseases, Intestinal disease, Colonic disease, Rectal disease
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 99-0411828
Code Inist : 002B13B01. Création : 22/03/2000.