Dietary intake of iron, heme-iron and magnesium and pancreatic cancer risk in the European prospective investigation into cancer and nutrition cohort

Several studies support a protective effect of dietary magnesium against type 2 diabetes, but a harmful effect for iron. As diabetes has been linked to pancreatic cancer, intake of these nutrients may be also associated with this cancer. We examined the association between dietary intake of magnesium, total iron and heme-iron and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. In total, 142,203 men and 334,999 women, recruited between 1992 and 2000, were included. After an average follow-up of 11.3 years, 396 men and 469 women developed exocrine pancreatic cancer. Hazard ratios and 95% confidence intervals (CIs) were obtained using Cox regression stratified by age and center, and adjusted for energy intake, smoking status, height, weight, and self-reported diabetes status. Neither intake of magnesium, total iron nor heme-iron was associated with pancreatic cancer risk. In stratified analyses, a borderline inverse association was observed among overweight men (body mass index, ≥25 kg/m ²) with magnesium (HR _{per 100 mg/day increase} = 0.79, 95% CI = 0.63-1.01) although this was less apparent using calibrated intake. In female smokers, a higher intake of heme-iron was associated with a higher pancreatic cancer risk (HR _{per 1 mg/day increase} = 1.38, 95% CI = 1.10-1.74). After calibration, this risk increased significantly to 2.5-fold (95% CI = 1.22-5.28). Overall, dietary magnesium, total iron and heme-iron were not associated with pancreatic cancer risk during the follow-up period. Our observation that heme-iron was associated with increased pancreatic cancer risk in female smokers warrants replication in additional study populations.