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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #199390
Title: IRON AND COLORECTAL CANCER RISK IN THE ALPHA-TOCOPHEROL, BETA-CAROTENE CANCER PREVENTION STUDY

Author
item CROSS, AMANDA - NATIONAL CANCER INSTITUTE
item GUNTER, MARC - NATIONAL CANCER INSTITUTE
item Wood, Richard
item PIENTINEN, PIRJO - HELSINKI, FINLAND
item TAYLOR, PHILIP - NATIONAL CANCER INSTITUTE
item VIRTAMO, JARMO - HELSINKI, FINLAND
item ALBANES, DEMETRIUS - NATIONAL CANCER INSTITUTE
item SINHA, RASHMI - NATIONAL CANCER INSTITUTE

Submitted to: International Journal of Cancer
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2005
Publication Date: 6/1/2006
Citation: Cross, A.J., Gunter, M.J., Wood, R.J., Pientinen, P., Taylor, P.R., Virtamo, J., Albanes, D., Sinha, R. 2006. Iron and colorectal cancer risk in the alpha-tocopherol, beta-carotene cancer prevention study. International Journal of Cancer. 118(12):3147-52.

Interpretive Summary: In vitro and in vivo studies have associated iron with both the initiation and promotional stages of carcinogenesis. We investigated whether iron was associated with colorectal cancer. Exposure was assessed at baseline, using a 276-item food frequency questionnaire and a fasting serum sample. The study included 130 colorectal cancer cases (73 colon cancers and 57 rectal cancers) and 260 controls. Comparing the highest to the lowest levels of a biomarker of iron stores in the body, there was an inverse association between iron stores and colorectal cancer risk and a suggestion of an inverse association between dietary iron and colorectal cancer risk. In summary, we found a significant inverse association between several serum iron indices and colon cancer risk. The association may indicate that low iron stores are a risk factor for colorectal cancer or it may indicate that those subjects who later developed colon cancer already had some degree of occult blood loss that lowered their iron stores.

Technical Abstract: In vitro and in vivo studies have associated iron with both the initiation and promotional stages of carcinogenesis. We investigated whether iron was associated with colorectal cancer in a nested case-control study within the a-tocopherol, b-carotene cancer prevention study cohort. Exposure was assessed at baseline, using a 276-item food frequency questionnaire and a fasting serum sample. The study included 130 colorectal cancer cases (73 colon cancers and 57 rectal cancers) and 260 controls. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Supplemental iron intake was only reported for 4 cases and 18 controls; therefore, we were unable to obtain meaningful results for this variable. Comparing the highest to the lowest quartiles, there was an inverse association between serum ferritin and colorectal cancer risk (OR 5 0.4, 95%CI 5 0.2–0.9) and a suggestion of an inverse association between dietary iron and colorectal cancer risk (OR 5 0.4, 95% CI 5 0.1–1.1). In addition, serum ferritin, serum iron and transferrin saturation were all inversely associated with colon cancer risk specifically (OR 5 0.2, 95% CI 5 0.1–0.7, p trend 5 0.02; OR 5 0.2, 95% CI 5 0.1–0.9, p trend 5 0.05; OR 5 0.1, 95% CI 5 0.02–0.5, p trend 5 0.003, respectively), whereas serum unsaturated iron binding capacity was positively associated with colon cancer risk (OR 5 4.7, 95% CI 5 1.4–15.1, p trend 5 0.009). In summary, we found a significant inverse association between several serum iron indices and colon cancer risk.