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

Study Overview
=================
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 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.

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

Conditions
-----------------
Lead Poisoning

Intervention / Treatment
-----------------
* Dietary Supplement: Ferrous fumarate
* Dietary Supplement: Zinc oxide
* Dietary Supplement: Placebo


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: 1st grade child Exclusion Criteria: Blood lead concentration =>45 ug/dL Hemoglobin concentration < 9 g/dL

Ages Eligible for Study
-----------------
Minimum Age: 6 Years
Maximum Age: 8 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Ferrous fumarate<br>Tablet formulated as ferrous fumarate, 30 mg. Given once daily for 6 months. | Dietary Supplement: Ferrous fumarate<br>* Tablet formulated from 30 mg ferrous fumarate.<br>|
| Experimental: Zinc oxide<br>Tablet formulated as zinc oxide, 30 mg. Given once daily by mouth for 6 months. | Dietary Supplement: Zinc oxide<br>* Tablet formulated from 30 mg zinc oxide<br>|
| Experimental: Ferrous fumarate and zinc oxide<br>Tablet, formulated as ferrous fumarate 30 mg plus zinc oxide 30 mg. Given once daily by mouth for 6 months. | Dietary Supplement: Ferrous fumarate<br>* Tablet formulated from 30 mg ferrous fumarate.<br>Dietary Supplement: Zinc oxide<br>* Tablet formulated from 30 mg zinc oxide<br>|
| Placebo Comparator: Placebo<br>Sugar tablet formulated to look like the experimental arms of the study. Given daily by mouth for 6 months. | Dietary Supplement: Placebo<br> <br> |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood lead concentration |  | 6-12 months | 

Secondary Outcome Measures

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

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
blood lead, iron, zinc, child, cognition, behavior, Mexico