Research Papers: Gastrointestinal CancerAssociation of dietary and supplemental iron and colorectal cancer in a population-based studyAshmore, Joseph H.a; Lesko, Samuel M.b; Miller, Paige E.f; Cross, Amanda J.g; Muscat, Joshua E.c; Zhu, Junjiac; Liao, Jasonc; Harper, Gregorye; Lazarus, Philipc,d; Hartman, Terryl J.aAuthor Information 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 Correspondence to Joseph H. Ashmore, BA, Department of Nutritional Sciences, Pennsylvania State University, 110 Chandlee Laboratory, University Park, PA 16802, USA Tel: +1 814 863 9692; fax: +1 814 863 6103; e-mail: [email protected] Received October 29, 2012 Accepted February 18, 2013 European Journal of Cancer Prevention: November 2013 - Volume 22 - Issue 6 - p 506-511 doi: 10.1097/CEJ.0b013e32836056f8 Buy Metrics 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. © 2013 Lippincott Williams & Wilkins, Inc.