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

Lead Poisoning Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02346188
• Other study ID #: H.22.00.07.06B
• Status: Completed
• Phase: N/A
• First received: January 20, 2015
• Last updated: January 23, 2015
• Start date: January 2000
• Est. completion date: December 2001

Study information

• Verified date: January 2015
• Source: Johns Hopkins Bloomberg School of Public Health
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Institutional Review Board
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 602
• Est. completion date: December 2001
• Est. primary completion date: December 2001
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 6 Years to 8 Years

Eligibility

Inclusion Criteria:

• 1st grade child

Exclusion Criteria:

• Blood lead concentration =>45 ug/dL

• Hemoglobin concentration < 9 g/dL

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Factorial Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Treatment

Related Conditions & MeSH terms

• Lead Poisoning

Intervention

Dietary Supplement:
• Ferrous fumarate
Tablet formulated from 30 mg ferrous fumarate.
• Zinc oxide
Tablet formulated from 30 mg zinc oxide
• Placebo

Locations

Country	Name	City	State
United States	Johns Hopkins Bloomberg School of Public Health	Baltimore	Maryland

Sponsors (3)

Lead Sponsor	Collaborator
Johns Hopkins Bloomberg School of Public Health	National Institute of Medical Sciences and Nutrition, Salvador Zubiran, National Polytechnic Institute, Mexico

Country where clinical trial is conducted

United States, 

References & Publications (9)

Kordas K, Canfield RL, López P, Rosado JL, Vargas GG, Cebrián ME, Rico JA, Ronquillo D, Stoltzfus RJ. Deficits in cognitive function and achievement in Mexican first-graders with low blood lead concentrations. Environ Res. 2006 Mar;100(3):371-86. Epub 200 — View Citation

Kordas K, Casavantes KM, Mendoza C, Lopez P, Ronquillo D, Rosado JL, Vargas GG, Stoltzfus RJ. The association between lead and micronutrient status, and children's sleep, classroom behavior, and activity. Arch Environ Occup Health. 2007 Summer;62(2):105-1 — View Citation

Kordas K, Lopez P, Rosado JL, García Vargas G, Alatorre Rico J, Ronquillo D, Cebrián ME, Stoltzfus RJ. Blood lead, anemia, and short stature are independently associated with cognitive performance in Mexican school children. J Nutr. 2004 Feb;134(2):363-71 — View Citation

Kordas K, Stoltzfus RJ, López P, Rico JA, Rosado JL. 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. — View Citation

Moodie S, Ialongo N, López P, Rosado J, García-Vargas G, Ronquillo D, Kordas K. The conjoint influence of home enriched environment and lead exposure on children's cognition and behaviour in a Mexican lead smelter community. Neurotoxicology. 2013 Jan;34:3 — View Citation

Rico JA, Kordas K, López P, Rosado JL, Vargas GG, Ronquillo D, Stoltzfus RJ. Efficacy of iron and/or zinc supplementation on cognitive performance of lead-exposed Mexican schoolchildren: a randomized, placebo-controlled trial. Pediatrics. 2006 Mar;117(3): — View Citation

Rosado JL, López P, Kordas K, García-Vargas G, Ronquillo D, Alatorre J, Stoltzfus RJ. Iron and/or zinc supplementation did not reduce blood lead concentrations in children in a randomized, placebo-controlled trial. J Nutr. 2006 Sep;136(9):2378-83. — View Citation

Rosado JL, Ronquillo D, Kordas K, Rojas O, Alatorre J, Lopez P, Garcia-Vargas G, Del Carmen Caamaño M, Cebrián ME, Stoltzfus RJ. Arsenic exposure and cognitive performance in Mexican schoolchildren. Environ Health Perspect. 2007 Sep;115(9):1371-5. — View Citation

Roy A, Kordas K, Lopez P, Rosado JL, Cebrian ME, Vargas GG, Ronquillo D, Stoltzfus RJ. Association between arsenic exposure and behavior among first-graders from Torreón, Mexico. Environ Res. 2011 Jul;111(5):670-6. doi: 10.1016/j.envres.2011.03.003. Epub — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Arsenic exposure	total urinary arsenic, inorganic arsenic, monomethylarsonic acid, dimethylarsinic acid	6-12 months	No
Primary	Blood lead concentration		6-12 months	No
Secondary	Anthropometric composite	Height, weight	6-12 months	No
Secondary	Serum ferritin concentration		6-12 months	No
Secondary	Serum zinc concentration		6-12 months	No
Secondary	Hemoglobin concentration		6-12 months	No
Secondary	Conners Behavior Rating Scales for parents and teachers		6-12 months	No
Secondary	Peabody Picture Vocabulary Test, Math achievement test, tests of attention and memory		6-12 months	No