High, low intakes of dietary iron linked to gastric cancer risk

Dietary iron intake appears to have a U-shaped association with the risk of gastric cancer, as suggested in a case–control study.

Researchers looked at 1,182 incident gastric cancer cases and 2,965 controls in Vietnam. Dietary iron intake was determined using a validated, semiquantitative food frequency questionnaire. An unconditional regression model was applied in the analyses.

Results showed a U-shaped association between dietary iron intake and gastric cancer. Compared with category 2 intake (reference group), category 1 (lowest) intake was associated with 64 -percent greater odds of gastric cancer (odds ratio [OR], 1.64, 95 percent confidence interval [CI], 1.27–2.12). The ORs also increased progressively across intake categories 3 (OR, 1.17, 95 percent CI, 0.90–1.53), 4 (OR, 1.35, 95 percent CI, 1.01–1.82), 5 (OR, 1.65, 95 percent CI, 1.18–2.31) , and 6 (OR, 2, 95 percent CI, 1.36–2.95; p<0.001 for trend).

The U-shaped association was consistently observed in men and women, with all types of dietary iron intake (ie, heme and nonheme), and among individuals with noncardia gastric cancer.

The association was more pronounced among individuals with a BMI of <23 kg/m² (p=0.02 for heterogeneity), never smokers (p=0.02 for heterogeneity), those without a family history of cancer (p=0.99 for heterogeneity), and individuals with blood group O (p=0.98 for heterogeneity). The association was also seen among both alcohol and coffee drinkers.