title: Association of dietary and supplemental iron and colorectal cancer in a population-based study.
abstract: We evaluated the role of dietary iron, heme iron, and supplemental iron on colorectal cancer (CRC) risk in a population-based case-control study in Pennsylvania, including 1005 incident cases and 1062 controls. Diet was assessed through a modified food frequency questionnaire that included supplement use and a meat-specific module. Cases reported intakes for the year before diagnosis, whereas controls reported intakes for the year before interview. Heme iron intake was calculated using a new heme database developed by the US National Cancer Institute. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression. After multivariate adjustment, there were no significant associations between heme iron or total iron intake and CRC incidence. Dietary iron intake was inversely associated with CRC among women (OR Q5 vs. Q1=0.45; 95% CI=0.22-0.92), but not among men. Supplemental iron intake of more than 18 mg/day versus none was positively associated with CRC incidence (OR=2.31; 95% CI=1.48-3.59; P-trend<0.001), an effect that was observed in both men (OR=2.56; 95% CI=1.30-5.05) and women (OR=2.46; 95% CI=1.34-4.52). These findings suggest that consumption of more than 18 mg/day of supplemental iron may increase risk for CRC.
authors.affiliation: aDepartment of Nutritional Sciences, Pennsylvania State University, University Park bNortheast Regional Cancer Institute, Scranton Departments of cPublic Health Sciences dPharmacology, Pennsylvania State College of Medicine, Hershey eDepartment of Medicine, Lehigh Valley Hospital, Allentown, Pennsylvania fDepartment of Health Sciences, Exponent Inc., Chicago, Illinois gDepartment of Health and Human Services, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Ashmore
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Lesko
authors.forename: Paige E
authors.initials: PE
authors.lastname: Miller
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Cross
authors.forename: Joshua E
authors.initials: JE
authors.lastname: Muscat
authors.forename: Junjia
authors.initials: J
authors.lastname: Zhu
authors.forename: Jason
authors.initials: J
authors.lastname: Liao
authors.forename: Gregory
authors.initials: G
authors.lastname: Harper
authors.forename: Philip
authors.initials: P
authors.lastname: Lazarus
authors.forename: Terryl J
authors.initials: TJ
authors.lastname: Hartman
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000209:etiology; D019587:Dietary Supplements; D005247:Feeding Behavior; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D058085:Iron Compounds / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
chemical_list: D058085:Iron Compounds