Individuals with different forms of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, carriers of the C677T mutation versus wild type, show differences in enzyme levels ; these differences have been hypothesized to be related to DNA methylation and, perhaps, to the nucleotide pool size.
Using data from an incident case-control study, we evaluated the combined effect of dietary intake of folate, methionine, vitamin B6, vitamin B12, and alcohol and various forms of the MTHFR gene on risk of colon cancer.
Individuals homozygous for the variant form of the MTHFR gene (TT) had a slightly lower risk of colon cancer than did individuals who were wild type [CC, odds ratio (OR)=0.8,95% confidence interval (CI)=0.6-1.1 for men ; and OR=0.9,95% CI=0.6-1.2 for women]. High levels of intake of folate, vitamin B6, and vitamin B12 were associated with a 30-40% reduction in risk of colon cancer among those with the TT relative to those with low levels of intake who were CC genotype.
Associations were stronger for proximal tumors, in which high levels of intake of these nutrients were associated with a halving of risk among those with the TT genotype.
The inverse association with high levels of these nutrients in those with the TT genotype was stronger among those diagnosed at an older age.
Although imprecise, the inverse association with the low-risk diet that was high in folate and methionine and without alcohol was observed for both the TT genotype (OR=0.4 95% CI=0.1-0. (...)
Mots-clés Pascal : Tumeur maligne, Côlon, Régime alimentaire, Methylenetetrahydrofolate reductase (NADPH), Oxidoreductases, Enzyme, Activité enzymatique, Epidémiologie, Facteur risque, Incidence, Homme, Californie, Etats Unis, Amérique du Nord, Amérique, Appareil digestif pathologie, Intestin pathologie, Côlon pathologie
Mots-clés Pascal anglais : Malignant tumor, Colon, Diet, Methylenetetrahydrofolate reductase (NADPH), Oxidoreductases, Enzyme, Enzymatic activity, Epidemiology, Risk factor, Incidence, Human, California, United States, North America, America, Digestive diseases, Intestinal disease, Colonic disease
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 99-0413212
Code Inist : 002B13B01. Création : 22/03/2000.