Dietary Iron and Heme Iron Consumption, Genetic Susceptibility, and Risk of Crohn's Disease and Ulcerative Colitis. Issue 7 (July 2017)

• Record Type: Journal Article
• Authors: Khalili, Hamed; de Silva, Punyanganie S.; Ananthakrishnan, Ashwin N.; Lochhead, Paul; Joshi, Amit; Garber, John J.; Richter, James R.; Sauk, Jenny; Chan, Andrew T.
• Is Part Of: Inflammatory bowel diseases. Volume 23:Issue 7(2017)
• Publication Date: 2017-07
• Subjects: inflammatory bowel disease -- Crohn's disease -- ulcerative colitis -- dietary heme -- iron intake -- genetic risk variants -- Nurses' Health study; Inflammatory bowel diseases -- Periodicals; Colitis, Ulcerative -- Periodicals; Crohn Disease -- Periodicals; Inflammatory Bowel Diseases -- Periodicals; 616.344
• DOI: 10.1097/MIB.0000000000001161
• Languages: English
• ISSNs: 1078-0998

Abstract

Abstract : Background: Dietary iron and heme, likely through their effect on gut commensal bacteria and colonic barrier function, have been shown to modulate colonic inflammation in animal models of colitis. Nonetheless, the link between dietary total and heme iron and risk of Crohn's disease (CD) and ulcerative colitis (UC) has not been previously explored. Methods: We conducted a prospective cohort study of 165, 331 U.S. women enrolled in the Nurses' Health Study and Nurses' Health Study II. Dietary information was collected using a validated food frequency questionnaire at baseline (1984) and updated every 2 to 4 years. Self-reported CD and UC diagnoses were confirmed through medical records review. We used Cox proportional hazard models to calculate hazard ratios and 95% confidence intervals while adjusting for potential confounders. In a case–control study nested within these cohorts, we evaluated the interaction between single-nucleotide polymorphisms associated with genome-wide susceptibility to CD and UC and dietary total and heme iron intake on risk of CD and UC using logistic regression modeling. Results: Through 2011, over 3, 038, 049 person-years of follow-up, we documented 261 incident cases of CD and 321 incident cases of UC. Dietary heme iron was nonsignificantly associated with increased risk of UC ( P trend = 0.12). This association seemed to be modified by the UC susceptibility locus, rs1801274, a coding variant in the Fc γ RIIA gene ( P interaction = 7.00E-05). In contrast, there was no association between dietary heme iron and risk of CD ( P trend = 0.67). We also did not observe an association between total dietary intake of iron and risk of CD or UC (All P trend > 0.35). Conclusion: In 2 large prospective cohort studies, dietary total and heme iron were not associated with risk of CD or UC. Our suggestive finding that the association between dietary heme iron intake and risk of UC may be modified by a coding variant in Fc γ RIIA gene warrants additional investigation. Abstract : Article first published online 9 June 2017.Supplemental Digital Content is Available in the Text.