Combined iron deficiency and lead poisoning in children. Effect on FEP levels.

Concern for the concomitant occurrence of iron deficiency and elevated blood lead in children is raised by animal studies documenting increased gastrointestinal lead absorption in the presence of iron deficiency. An elevation in free erythrocyte protoporphyrin (FEP) above 35 mg/dl is seen with both iron deficiency and lead toxicity. To determine whether the degree of elevation in FEP is useful in predicting which children with elevated blood lead levels have concomitant iron deficiency, 109 children suspected of having an elevated lead burden were studied. A complete blood count, reticulocyte count, FEP, lead, and ferritin were measured on each child. The effect of the independent variables, lead and iron status, both alone and in combination, on the dependent variable, FEP, was analyzed through a linear regression model. Lead status alone accounted for 42 percent of the explained variance in FEP, and the lead-iron interaction increased the explained variance by only an additional 1 percent. Screening for iron deficiency in children with elevated blood lead should continue to be based on dietary and socioeconomic risk factors and not on degree of elevation in FEP.