Dietary iron and risk of myocardial infarction in the Rotterdam Study

Free iron has been implicated in lipid peroxidation and ischemic myocardial damage, and it has been suggested that iron is an independent risk factor for myocardial infarction. The authors investigated whether dietary iron is associated with an increased risk of fatal and nonfatal myocardial infarct ion in the Rotterdam Study, a community-based prospective cohort study of 7 ,983 elderly subjects in Rotterdam, the Netherlands. The study sample consi sted of 4,802 participants who at baseline had no known history of myocardi al infarction and for whom dietary data were available. From 1990 to 1996, 124 subjects had a myocardial infarction. No association was observed betwe en total iron intake and risk of myocardial infarction after adjustment for age and sex (relative risk for the highest vs. the lowest tertile of intak e = 0.89, 95% confidence interval (CI) 0.55-1.45, p for trend = 0.640). Hem e iron intake was positively associated with risk of myocardial infarction (relative risk for the highest vs. the lowest tertile of intake = 1.83, 95% CI 1.16-2.91, p for trend = 0.008) after adjustment for age and sex, and t his association persisted after multivariate adjustment (relative risk = 1. 86, 95% CI 1.14-3.09, p for trend = 0.010), A distinction between fatal and nonfatal cases of myocardial infarction indicated that the association of heme iron with myocardial infarction was more pronounced in fatal cases. Th e results suggest that a high dietary heme iron intake is related to an inc reased risk of myocardial infarction and that it may specifically affect th e rate of fatality from myocardial infarction.