Association between iron deficiency and blood lead level in a longitudinal analysis of children followed in an urban primary care clinic

Objective: To determine if iron deficiency (ID) is longitudinally associated with lead poisoning. Study design: Blood lead levels, hemoglobin, mean corpuscular volume (MCV), red cell distribution width (RDW), insurance status, and age were determined for 1275 children. ID was defined as MCV <70 fl and RDW >14.5 if age was <2 years and MCV >73 fl and RDW <14.5 if age was ≥2 years. Logistic regression models were constructed by using the second-visit blood lead levels dichotomized at ≥0.48 μm/L (10 μg/dL) as the outcome. Results: The odds ratio (OR) for baseline ID predicting lead poisoning at the second visit was 4.12 (95% CI, 1.96-8.65). In the second model, using children who were iron-replete at both visits as the referent group, for children with ID at both visits, the OR for predicting lead poisoning at the second visit was 5.54 (95% CI, 2.25-13.62). For children with ID at the first visit and iron-replete at the second visit, the OR was 2.73 (95% CI, 0.90-8.27), and for children iron-replete at the first visit and ID at the second visit, the OR was 0.81 (95% CI, 0.10-6.30). Conclusions: ID is associated with subsequent lead poisoning. These data are consistent with a biological mechanism of increased lead absorption among iron deficient children.