The association of urine markers of iodine intake with development and growth among children in rural Uganda: a secondary analysis of a randomised education trial.

OBJECTIVE: We examined associations of urine iodide excretion, proxy for iodine intake, with child development and growth. DESIGN: This is a secondary analysis of a 1:1 cluster-randomised trial with a 6-month nutrition/stimulation/hygiene education intervention among mothers of children aged 6-8 months to improve child development and growth. Development was assessed using Bayley Scales of Infant and Toddler Development-III (BSID-III) and Ages and Stages Questionnaire (ASQ), whereas anthropometry was used to assess growth. Urine iodide concentration (UIC) and urine iodide/creatinine ratio (ICR) were measured. SETTING: The current study was conducted in southern Uganda. PARTICIPANTS: We randomly selected 155 children from the 511 enrolled into the original trial and analysed data when they were aged 20-24 and 36 months. RESULTS: Median UIC for both study groups at 20-24 and 36 months were similar (P > 0·05) and within the normal range of 100-199 µg/l (0·79-1·60 µmol/l), whereas the intervention group had significantly higher ICR at 20-24 months. The BSID-III cognitive score was positively associated (P = 0·028) with ICR at 20-24 months in the intervention group. The ASQ gross motor score was negatively associated (P = 0·020) with ICR at 20-24 months among the controls. ICR was not significantly associated with anthropometry in the two study groups at either time-point. CONCLUSIONS: Following the intervention, a positive association was noted between ICR and child's cognitive score at 20-24 months, whereas no positive association with ICR and growth was detected. Iodine sufficiency may be important for child's cognitive development in this setting.