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

Johns Hopkins Bloomberg School of Public Health

Status: Completed

Conditions: Lead Poisoning

Treatments: Dietary Supplement: Placebo; Dietary Supplement: Zinc oxide; Dietary Supplement: Ferrous fumarate

Study type: Interventional

Funder types: Other

Identifiers

NCT02346188

H.22.00.07.06B

Details and patient eligibility

About

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.

Full description

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.

Enrollment: 602 patients

Sex: All

Ages: 6 to 8 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• 1st grade child

Exclusion criteria

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

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Factorial Assignment

Masking: Quadruple Blind

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602 participants in 4 patient groups, including a placebo group

Ferrous fumarate

Experimental group

Description:

Tablet formulated as ferrous fumarate, 30 mg. Given once daily for 6 months.

Treatment:

Dietary Supplement: Ferrous fumarate

Zinc oxide

Experimental group

Description:

Tablet formulated as zinc oxide, 30 mg. Given once daily by mouth for 6 months.

Treatment:

Dietary Supplement: Zinc oxide

Ferrous fumarate and zinc oxide

Experimental group

Description:

Tablet, formulated as ferrous fumarate 30 mg plus zinc oxide 30 mg. Given once daily by mouth for 6 months.

Treatment:

Dietary Supplement: Zinc oxide

Dietary Supplement: Ferrous fumarate

Placebo

Placebo Comparator group

Description:

Sugar tablet formulated to look like the experimental arms of the study. Given daily by mouth for 6 months.

Treatment:

Dietary Supplement: Placebo