Joint association of magnesium and iron intake with anemia among Chinese adults

Objective Inflammation and iron deficiency are two important causes of anemia. Magnesium intake is inversely associated with inflammation. However, little is known as to whether magnesium intake is related to anemia. We assessed the joint association of magnesium and iron intake with anemia among Chinese adults. Methods A cross-sectional household survey of 2849 men and women 20 y of age or older was conducted in 2002. Nutrient intakes were assessed by 3-d weighed food records. Serum ferritin and hemoglobin concentrations were measured. Results The prevalence of anemia was 18.3% in men and 31.5% in women. Magnesium and iron intakes were positively associated with hemoglobin levels and inversely related to the prevalence of anemia. The risks of anemia were reduced by 26% (P for trend = 0.03) and 52% (P < 0.01), respectively, for iron and magnesium intake comparing the fourth quartile with the first with adjustment for potential confounders. The lowest risk of anemia was observed among participants with the highest intakes of magnesium and iron (odds ratio 0.46, 95% confidence interval 0.31–0.68). The inverse association of iron intake and anemia but not the association of magnesium intake and anemia was modified by serum ferritin levels. The observed relations were not appreciably modified by gender. Conclusion This study suggests that magnesium is a potent predictor of anemia in Chinese adults.