Iron and zinc supplementation does not improve parent or teacher ratings of behavior in first grade Mexican children exposed to lead

J Pediatr. 2005 Nov;147(5):632-9. doi: 10.1016/j.jpeds.2005.06.037.


Objective: To determine the efficacy of iron and zinc supplementation on behavior ratings of lead-exposed children.

Study design: In this double-blind, randomized trial, 602 first-grade children received 30 mg ferrous fumarate, 30 mg zinc oxide, both, or placebo daily for 6 months. Lead, iron, and zinc status were determined at baseline and follow-up. Parents and teachers provided ratings of child behavior using the Conners Rating Scales.

Results: The baseline mean (SD) blood lead concentration was 11.5 (6.1) mug/dL, with 51% of children > or = 10 microg/dL. The prevalence of attention deficit hyperactivity disorder, estimated by combined parent and teacher ratings, was 6%. At follow-up, parent ratings of oppositional, hyperactive, cognitive problems, and attention deficit hyperactivity disorder decreased by 1.5, 1.2, 2.5, and 3.4 points, respectively (P < .05). Teacher ratings of hyperactivity increased by 1.1 points (P = .008), and the mean cognitive problem score declined by 0.7 points (P = .038). There were no treatment effects on mean change in scores, but children receiving any zinc had a higher likelihood of no longer receiving clinically-significant teacher ratings of oppositional behaviors.

Conclusions: This regimen of supplementation did not result in consistent improvements in ratings of behavior in lead-exposed children over 6 months.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Attention Deficit and Disruptive Behavior Disorders / epidemiology
  • Attention Deficit and Disruptive Behavior Disorders / etiology
  • Attention Deficit and Disruptive Behavior Disorders / prevention & control*
  • Child
  • Double-Blind Method
  • Drug Therapy, Combination
  • Environmental Exposure / adverse effects*
  • Female
  • Humans
  • Iron / administration & dosage
  • Iron / deficiency
  • Iron / therapeutic use*
  • Lead / adverse effects
  • Lead / blood*
  • Linear Models
  • Logistic Models
  • Male
  • Mexico / epidemiology
  • Zinc / administration & dosage
  • Zinc / deficiency
  • Zinc / therapeutic use*


  • Lead
  • Iron
  • Zinc