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The Effects of Iodized Salt on Cognitive Development in Ethiopia

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT01349634
First Posted: May 6, 2011
Last Update Posted: June 9, 2016
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Collaborators:
Micronutrient Initiative
Ethiopian Health and Nutrition Research Institute
Information provided by (Responsible Party):
Grace S. Marquis, McGill University
April 20, 2011
May 6, 2011
June 9, 2016
October 2011
May 2014   (Final data collection date for primary outcome measure)
  • cognitive development at 6 mo [ Time Frame: 6 months ]
    Bayley Scales of Infant and Toddler Development III cognitive, language, and fine motor scales
  • Cognitive development at 18 mo [ Time Frame: 18 months ]
    Bayley Scales of Infant and Toddler Development III cognitive, language, and fine motor scales
  • cognitive development at 60 mo [ Time Frame: 60 months ]
    two Wechsler Preschool and Primary School Intelligence subscales plus a School Readiness test
  • cognitive development at 6 mo [ Time Frame: 6 months ]
    Bayley cognitive, language, and fine motor scales
  • Cognitive development at 18 mo [ Time Frame: 18 months ]
    Bayley cognitive, language, and fine motor scales
  • cognitive development at 60 mo [ Time Frame: 60 months ]
    two WPPSI subscales plus a School Readiness test
Complete list of historical versions of study NCT01349634 on ClinicalTrials.gov Archive Site
  • nutritional status at 6 mo [ Time Frame: 6 months ]
    weight, length/height, iodine and iron status
  • nutritional status at 18 mo [ Time Frame: 18 months ]
    weight, length/height, iodine and iron status
  • nutritional status at 60 mo [ Time Frame: 60 months ]
    weight, length/height, iodine and iron status
Same as current
Not Provided
Not Provided
 
The Effects of Iodized Salt on Cognitive Development in Ethiopia
A Study to Measure the Effect of Switching the Salt Supply From Non-iodized to Iodized on Cognitive Development in Ethiopia
Many school children in Ethiopia and their mothers are known to be iodine deficient. Prevalence in the Amhara region is around 29%. Micronutrient Initiative, a development organization based in Ottawa, plans to help iodize the salt by providing iodization machines and iodine to the salt producers in Lake Afdira where salt is produced and distributed to the population of Ethiopia. Although it is generally assumed that iodine is important for cognitive development, very few studies examining the effects of iodized salt have been conducted. Studies using a single dose of iodine capsules with children 6 to 12 years showed mixed outcomes with approximately 25% yielding positive outcomes for the intervention children. Sixty districts in Amhara will be randomly selected and randomly assigned so that half receive early delivery of iodized salt. Approximately 6200 mothers and their children 6-, 18-, or 60-months old will be recruited from 1-2 villages in each of the 60 districts, with the help of government-paid Health Extension Workers, for a 12-mo longitudinal study starting in May 2011, prior to the introduction of iodized salt. These same mothers and children will be visited 12 months later for repeated measures. Measures include nutritional status such as height and hemoglobin, along with iodine sufficiency (e.g., goitre, urinary iodine, thyroglobulin), and child development (Bayley Scales of Infant and Toddler Development III, Wechsler Preschool and Primary School Intelligence test for older children). Comparisons will be made within and between groups to determine whether iodized salt has an effect on children's mental development.

MATERIALS AND METHODS Sample size was estimated on the basis of the Bayley Scales of Infant and Toddler Development III (Bayley) where the mean is 100 and the standard deviation is 15. Using an effect size of 0.20 standard deviation, a beta of .05 and power of .80, and accommodating for clustering within villages and attrition, the investigators require a sample size of 800 for each group (intervention and control). Severely anemic children (< 8 mg/L) will be referred for treatment and not included in the study.

In this longitudinal study the investigators will recruit 3200 6-mo old infants and 1600 children from each of two other age groups: 18-, and 60-months (inclusion criteria) and their mothers. The exclusion criteria: severe anemia (hemoglobin < 8g/dL). If children are too disabled to take a cognitive test, this will be noted but no cognitive testing administered.

From six zones around Bahir Dar, the investigators will randomly select 60 districts. Half will be assigned randomly to start receiving iodized salt in July 2011; the other half will receive iodized salt as it becomes available in the market. From each district, 1-2 villages will be randomly selected for recruiting 30 children from each age group. It is assumed that with a pregnancy rate of 3.7%, approximately 166 children are born every year in a village of 4500, and 13 are born every month. So within 3 months, starting in May 2011, 30 children of each age could be recruited.

With the help of Health Extension Workers, trained field workers will identify the participants : children of eligible age. Mothers will provide written consent for themselves and their children to participate.

Mothers will be interviewed at baseline and endline concerning the family's economic and demographic information, child's health and diet, and opportunities for stimulation of children (Home Observation for Measurement of the Environment Inventory; Center for Epidemiologic Studies Depression Scale symptom scores). Children's nutritional status will be measured with a food frequency questionnaire, length/height, weight, blood indicators for thyroid function (thyroglobulin, thyroxin, triiodothyronine) and iron status (hemoglobin, ferritin, soluble transferrin receptor), and inflammation (C-reactive protein), goiter, and urinary iodine. A maximum of 10 mL will be collected for blood by venipuncture. Finally, trained assistants will administer the Bayley Scales of Infant and Toddler Development III (cognitive, language, and fine motor scales) to children under-3 years and two Wechsler Preschool and Primary School Intelligence test subscales and School Readiness test for 60-month olds. Salt will be collected at various places of purchase and in households to test for iodine content (first qualitatively, then quantitatively if iodized) at baseline and at the end of the study. All data collection will be done at home or a convenient site in the village.

Conversion of diet into iodine content will be done based on food composition table. Anthropometric data will be converted to standardized scores using the new World Health Organization reference curves, using World Health Organization's software Anthro v. 2 for children up to 60 months of age.

Analyses will compare the nutritional and developmental outcomes of two groups who differ in iodized salt exposure, covarying confounders such as mother's education, family assets, child's sex, and adjusting for clustering. Developmental scores will be derived for the Bayley subtests, and the Wechsler Preschool and Primary School Intelligence test. These tests typically assign 1 point for every correct answer and 0 points for incorrect answers; the summed continuous scores are then used for analysis. Potential confounds include the Home Observation for Measurement of the Environment Inventory and Center for Epidemiologic Studies Depression Scale symptom scores, which also are calculated as the sum of individual item points. Laboratory analyses will be conducted to determine hemoglobin, ferritin, soluble transferrin receptor, thyroglobulin, thyroxin, and triiodothyronine from blood samples, and iodine excretion from urine samples. Analyses of salt will also indicate whether salt consumed by participants in the intervention districts has the required ppm of iodine and more than salt consumed in control districts. If households in the control sites have higher than expected levels of iodine, this will be recorded and included in the analyses.

Interventional
Not Provided
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Prevention
  • Iodine Deficiency
  • Goiter
  • Cretinism
Other: Iodized salt
salt for human consumption is fortified at the national level with iodine. The experimental group will receive iodized salt early. the comparison group will receive it by market forces. presently there is only enough iodized salt to meet 10% of the countries needs, and is targeted mainly to urban areas.
  • No Intervention: Comparison group
    This arm will use the salt that is on the open market, which is primarily non-iodized salt. Iodized salt may enter in these communities through the normal trade route. No active interference with salt trade will occur in these communities.
  • Experimental: Early delivery of iodized salt
    Iodized salt that is produced nationally for the open market (which meets only about 10% of national needs) will be directed to these communities through the normal trade system or by direct delivery to the communities.
    Intervention: Other: Iodized salt
Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
5704
May 2014
May 2014   (Final data collection date for primary outcome measure)

Inclusion Criteria:

  • children within 15 days of 6, 18, and 60 months

Exclusion Criteria:

  • severe cognitive impairment so child cannot respond to Bayley Scales of Infant and Toddler Development III test
Sexes Eligible for Study: All
5 Months to 61 Months   (Child)
Yes
Contact information is only displayed when the study is recruiting subjects
Canada
 
 
NCT01349634
10-1152-MCGUNI-01
No
Not Provided
Not Provided
Grace S. Marquis, McGill University
McGill University
  • Micronutrient Initiative
  • Ethiopian Health and Nutrition Research Institute
Principal Investigator: Grace S Marquis, PhD McGill University
Principal Investigator: Frances Aboud, PhD McGill University
Principal Investigator: Aregash Samuel, MSc Ethiopian Health and Nutrition Research Institute
McGill University
June 2016

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP