Skip to main content
OpenTrials
Completed

NCT Number: NCT02346188

Effects of Iron and/or Zinc Supplementation in Mexican School Children Exposed to Lead

Lead is negatively linked to nutritional status, behavior and cognition in children. Despite extensive knowledge of its toxicity and efforts to reduce exposure, lead continues to be a problem in developed and developing countries. When lead exposure is unavoidable due to its pervasive nature, effective means of protecting or disrupting that exposure need to be developed. Nutritional interventions are one such option. We conducted a 2x2 factorial, placebo-controlled trial of 6-month iron and zinc supplementation among lead-exposed children in Torreón, Mexico (altitude 1060 m). Nine schools were selected based on proximity to a lead smelter and first-graders were individually randomized to daily treatment with 30 mg iron, 30 mg zinc, both, or placebo. In addition to biochemical indicators, cognitive functions and behavior were evaluated at baseline, after the 6-month supplementation period, and again after another 6 months (without supplementation).

At baseline, 602 children ages 6.2-8.5 years were enrolled.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Lead Poisoning Behavior Chemically-Induced Disorders Heavy Metal Poisoning Poisoning

Age range

6 year–8 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Johns Hopkins Bloomberg School of Public Health

Baltimore, Maryland, 21205, United States

About this study

We conducted a 2x2 factorial, placebo-controlled trial of 6-month iron and zinc supplementation among lead-exposed children in Torreón, Mexico (altitude 1060 m) to test the hypothesis that supplementation with iron, zinc or both will reduce blood lead concentrations of the children and improve their cognition and behavior. Nine schools were selected based on proximity to a lead smelter and first-graders were individually randomized to daily treatment with 30 mg iron, 30 mg zinc, both, or placebo. In addition to biochemical indicators (blood lead, serum ferritin, CRP, serum zinc, urinary arsenic concentrations), cognitive functions and behavior were measured. Assessments were conducted at three time points: at baseline, after the 6 month treatment, and again after another 6 months without treatment. At baseline, 602 children ages 6.2-8.5 years were enrolled.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 1st grade child

Exclusion criteria

  • Blood lead concentration =>45 ug/dL
  • Hemoglobin concentration < 9 g/dL

Treatment and study plan

ferrous fumarate

Dietary Supplement

Tablet formulated from 30 mg ferrous fumarate.

Zinc oxide

Dietary Supplement

Tablet formulated from 30 mg zinc oxide

Placebo

Dietary Supplement

Primary outcomes

  1. Blood lead concentration

    Time frame: 6-12 months

Secondary outcomes

  1. Anthropometric composite

    Time frame: 6-12 months

    Height, weight

  2. Serum ferritin concentration

    Time frame: 6-12 months

  3. Serum zinc concentration

    Time frame: 6-12 months

  4. Hemoglobin concentration

    Time frame: 6-12 months

  5. Conners Behavior Rating Scales for parents and teachers

    Time frame: 6-12 months

  6. Peabody Picture Vocabulary Test, Math achievement test, tests of attention and memory

    Time frame: 6-12 months

Other outcomes

  1. Arsenic exposure

    Time frame: 6-12 months

    total urinary arsenic, inorganic arsenic, monomethylarsonic acid, dimethylarsinic acid

Sponsors and collaborators

Lead sponsor

Johns Hopkins Bloomberg School of Public Health

Other

Collaborators

  • National Institute of Medical Sciences and Nutrition, Salvador Zubiran
  • National Polytechnic Institute, Mexico

Registry information

Official study title

Effects of Iron and Zinc Supplementation on Neuropsychological and Educational Achievement in Lead-exposed School Children

Important dates

Study start
2000
Primary completion
2001
Study completion
2001
First posted
Jan 26, 2015
Registry last updated
Jan 26, 2015

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.