Evaluation of the effects of iodized salt on the mental development of preschool‐aged children: a cluster randomized trial in northern Ethiopia
Bibliographic record
Abstract
A cluster randomized effectiveness trial was used to examine the effects on mental development of introducing iodized salt to children 4 to 6 years of age in Ethiopia, where there were reportedly high levels of iodine deficiency. Sixty district clusters were randomized to receive iodized salt early at their markets with assistance from regular salt distributors or later as introduced by market forces. At pre- and post-iodization, 1602 children were given cognitive/language tests (namely School Readiness, WPPSI verbal reasoning, WPPSI Matrix reasoning), and mothers were interviewed concerning demographics, nutrition and health. Children's weight, height, urine and a blood sample were taken. Analyses of covariance, adjusting for clustering and baseline levels were conducted. Urinary iodine concentrations were significantly higher at endline in the intervention children than controls though both medians were above threshold. Overall, less than 5% were anemic. There were no significant main effect differences between groups on the cognitive/language tests, but there were effect modifiers, namely mother's education, child's sex and diet. For example, the intervention group performed better on the school readiness test than controls if their mothers had attended school, but not otherwise. In conclusion, the data are consistent with negative findings from studies where children 6 to 12 years were supplemented with an iodine capsule, indicating that the benefits of iodine, in salt or capsule form, for brain development may be restricted to children under 3 years. Yet, benefits may be tied to those with more educational resources or may compensate for conditions of disadvantage.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".