Supplementary iron intake and risk of cancer: reversed causality?
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.
Ullén
H
H
Department of Cancer Prevention, Karolinska Hospital, Stockholm, Sweden.
Augustsson
K
K
Gustavsson
C
C
Steineck
G
G
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
D007501:Iron