The Effects of Iodized Salt on Cognitive Development in Ethiopia
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|ClinicalTrials.gov Identifier: NCT01349634|
Recruitment Status : Completed
First Posted : May 6, 2011
Last Update Posted : June 9, 2016
|Condition or disease||Intervention/treatment||Phase|
|Iodine Deficiency Goiter Cretinism||Other: Iodized salt||Not Applicable|
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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.
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||5704 participants|
|Intervention Model:||Parallel Assignment|
|Masking:||None (Open Label)|
|Official Title:||A Study to Measure the Effect of Switching the Salt Supply From Non-iodized to Iodized on Cognitive Development in Ethiopia|
|Study Start Date :||October 2011|
|Actual Primary Completion Date :||May 2014|
|Actual Study Completion Date :||May 2014|
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.
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.
- 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
- 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
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01349634
|Montreal, Quebec, Canada, H3A 2T5|
|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|