title: Supplementary iron intake and risk of cancer: reversed causality?
abstract: Dietary iron intake and body iron stores have been suggested to increase cancer risk, especially colorectal cancer. Within a population-based case-control study in Stockholm county 1993-94, information on dietary and supplementary iron intake were collected through a food frequency questionnaire. An initially noted positive association between intake of supplementary iron and colorectal cancer risk was reversed when intake 5 years prior to cancer diagnosis was subtracted. Reversed causality due to early disease giving symptoms of iron shortage, resulting in iron supplementation, is an issue to consider when a possible association between intake of iron and cancer risk is investigated.
authors.affiliation: Department of Cancer Prevention, Karolinska Hospital, Stockholm, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Ullén
authors.forename: K
authors.initials: K
authors.lastname: Augustsson
authors.forename: C
authors.initials: C
authors.lastname: Gustavsson
authors.forename: G
authors.initials: G
authors.lastname: Steineck
mesh_terms: D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D003110:Colonic Neoplasms / Q000209:etiology*; D005527:Food, Fortified; D006801:Humans; D007501:Iron; D008875:Middle Aged; D012004:Rectal Neoplasms / Q000209:etiology*; D012307:Risk Factors; D012737:Sex Factors
chemical_list: D007501:Iron