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Unformatted text preview: Folate, vitamin B12 and postmenopausal breast cancer in a prospective study of French women Martin Lajous 1,2 , Isabelle Romieu 2 , Severine Sabia 1 , Marie-Christine Boutron-Ruault 1 , and Franoise Clavel-Chapelon 1,* 1 Nutrition, hormones et cancer: pidmiologie et prventionINSERM : ERI20, IFR69, Universit Paris Sud- Paris XI, EA4045, Institut Gustave-Roussy 39 rue Camille Desmoulins 94805 Villejuif CEDEX,FR. 2 Center for Population Health ResearchInsituto Nacional de Salud Publica, Cuernavaca, Mexico,MX. Abstract Objective Adequate folate intake may be important for breast cancer prevention. Its protective effect may be influenced by factors associated with folate metabolism. We sought to evaluate folate intake in relation to breast cancer risk and examine whether the relation is affected by alcohol and intake of vitamin B 2 and B 12 . Methods A prospective cohort analysis of folate intake was conducted among 62,739 postmenopausal women in the French E3N cohort who had completed a validated food frequency questionnaire in 1993. During nine years follow-up, 1,812 cases of pathology-confirmed breast cancer were documented through follow-up questionnaires. Nutrients were categorized in quintiles and energy-adjusted using the regression-residual method. Cox model-derived relative risks (RRs) were adjusted for known breast cancer determinants. Results The multivariate RR for extreme quintiles of folate intake was was 0.78 (95% CI: 0.67 0.90; p-trend = 0.001) [Median intake for Q 1 = 296 g/day and Q 5 = 522 g/day]. There was no evidence to support effect modification by alcohol or B 2 intake. The decreasing trend was most marked in women with higher folate and vitamin B 12 intake. However, test for interaction was not statistically significant ( p = 0.29) Conclusions High folate intake was associated with decreased breast cancer risk. Vitamin B 12 intake may modify this association. Keywords Adult; Alcohol Drinking; Breast Neoplasms; epidemiology; Eating; Energy Intake; Female; Folic Acid; administration & dosage; Follow-Up Studies; France; epidemiology; Humans; Middle Aged; Multivariate Analysis; Postmenopause; Proportional Hazards Models; Prospective Studies; Questionnaires; Research Design; Riboflavin; administration & dosage; Risk Factors; Vitamin B 12; administration & dosage; Vitamin B Complex; administration & dosage Introduction Substantial experimental and epidemiologic research has shown that low folate intake can increase cancer occurrence . Diminished folate status may disrupt DNA synthesis and repair mechanisms and may influence gene expression through abnormal DNA and RNA methylation . Furthermore, the metabolic pathway involved in DNA methylation requires the presence of other micronutrients like vitamins B 2 and B 12 as cofactors and may be inhibited by ethanol * Correspondence should be adressed to: Franoise Clavel-Chapelon firstname.lastname@example.org HAL Archives Ouvertes France Author Manuscript Accepted for publication in a peer reviewed journal.Accepted for publication in a peer reviewed journal....
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This note was uploaded on 11/06/2010 for the course NS 1150 taught by Professor Levitsky during the Spring '05 term at Cornell University (Engineering School).
- Spring '05
- The Land