Relationship of vitamin A deficiency, iron deficiency, and inflammation to anemia among preschool children in the Republic of the Marshall Islands

Introduction: Although vitamin A deficiency, iron deficiency, and inflammation may contribute to anemia, their relative contribution to anemia has not been well characterized in preschool children in developing countries. Objective: To characterize the contributions of vitamin A and iron deficiencies and inflammation to anemia among preschool children in the Republic of the Marshall Islands. Subjects and methods: A community-based survey, the Republic of the Marshall Islands Vitamin A Deficiency Study, was conducted among 919 preschool children. The relationship of vitamin A and iron status and markers of inflammation, tumor necrosis factor-alpha, alpha(1)-acid glycoprotein, and interleukin-10, to anemia were studied in a subsample of 367 children. Results: Among the 367 children, the prevalence of anemia was 42.5%. The prevalence of severe vitamin A deficiency ( serum vitamin A <0.35 mu mol/l) and iron deficiency ( serum ferritin <12 mug/dl) were 10.9 and 51.7%, respectively. The respective prevalence of iron deficiency anemia ( hemoglobin <110 g/l and iron deficiency), anemia with inflammation ( anemia with TNF-alpha >2 pg/ml and/or AGP >1000 mg/l), and severe vitamin A deficiency combined with anemia was 26.7, 35.6, and 7.6%. In multivariate linear regression models that adjusted for age, sex, and inflammation, both iron deficiency (odds ratio (OR) 1.74, 95% confidence interval (CI) 1.08 - 2.83, P = 0.023) and severe vitamin A deficiency (OR 4.85, 95% CI 2.14 - 10.9, P<0.0001) were significantly associated with anemia. Conclusions: Both iron and vitamin A deficiencies were independent risk factors for anemia, but inflammation was not a significant risk factor for anemia among these preschool children.