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

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

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

Brief Summary:

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.


Detailed Summary: 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.
Sponsor: Johns Hopkins Bloomberg School of Public Health

Current Primary Outcome: Blood lead concentration [ Time Frame: 6-12 months ]

Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Anthropometric composite [ Time Frame: 6-12 months ]
    Height, weight
  • Serum ferritin concentration [ Time Frame: 6-12 months ]
  • Serum zinc concentration [ Time Frame: 6-12 months ]
  • Hemoglobin concentration [ Time Frame: 6-12 months ]
  • Conners Behavior Rating Scales for parents and teachers [ Time Frame: 6-12 months ]
  • Peabody Picture Vocabulary Test, Math achievement test, tests of attention and memory [ Time Frame: 6-12 months ]


Original Secondary Outcome: Same as current

Information By: Johns Hopkins Bloomberg School of Public Health

Dates:
Date Received: January 20, 2015
Date Started: January 2000
Date Completion:
Last Updated: January 23, 2015
Last Verified: January 2015