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Table 3 Characteristics and summary of findings of studies (n = 5) investigating associations between maternal dietary iodine intakes and child cognitive outcomes

From: Associations between maternal urinary iodine assessment, dietary iodine intakes and neurodevelopmental outcomes in the child: a systematic review

Author Country Design N Gestational age at dietary assessment Child age at testing Cognitive tests conducted Dietary measurement Association to cognitive outcomes Quality check
Abel, M.H. et al., 2017 [22] Norway Prospective cohort 77,164 mother child pairs at 22 weeks 9.9 (median) ADHD Rating Scale FFQ Median 121 μg/d *contributed to by Milk, yoghurt, eggs, fish. Iodine intake < 200 μg/d, associated with higher child ADHD symptom scores (p < 0.001). 9
Abel, M.H. et al., 2018 [23] Norway Prospective cohort 39,471 mother child pairs 0–22 8 CCCS; Vineland Adaptive Behaviour Scale; Performance tests for reading, writing and maths. FFQ: Median intake from food 122 μg/d Milk/Yoghurt (47%) Lean fish (14%), Egg (4%), Fatty fish (4%), Other foods (17%) and drinking water (2%) Low dietary iodine intake associated with poorer language(p = 0.013), reading (p = 0.019), and writing skills (p = 0.004). Increased likelihood of special needs education (p = 0.042)-all in non-supplement users 9
Murcia, M. et al., 2018 [24] Spain Prospective cohort 2644 women recruited and 1803 children. 10–13 and 28–32 4.8 MSCA FFQ: 161 μg/d (mean iodine intake) Milk, yoghurt, cheese.
45.8% consumed iodized salt and 34.2% a supplement containing iodine.
Dietary iodine was inversely associated with motor scores and milk, but not other dairy products or seafood consumption (beta: −1.36; 95%CI −2.12 to −0.61; per one daily milk serving). 9
Zhou, S.J. et al., 2018 [25] Australia Prospective cohort 699 mother child pairs < 20 and 28 19.5 months BSID-III IFFQ mean total iodine intake 309 μg/d and 150 μg/d when supplements were excluded. Fortified bread, accidental supplement use and iodized salt. Maternal iodine intake in the lowest (< 220 μg/day) or highest (≥391 μg/day) quartile was associated with lower cognitive, language, and motor scores OR’s 2.7 (95% CI: 1.3, 5.6) to 2.8 (95% CI: 1.3, 5.7)) 9
Van Mil, N.H. et al., 2012 [21] Netherlands Prospective cohort 1156 mothers and 692 children 13.2 (median) 4 BRIEF-P FFQ consumption of bread [b = 0.61 (95% CI: 0.27, 0.95), P < 0.001] and eggs (b = 1.87 (95% CI: 0.13, 3.62), P = 0.04] was associated with higher urinary iodine. NS 9
  1. ADHD Attention-Deficit Hyperactivity Disorder, NS No significance, FFQ Food Frequency Questionnaire, CCCS The Children’s Communication Checklist-short, CI Confidence Intervals, MSCA McCarthy Scales of Children’s Abilities, BSID-III Bayley’s Scale of Infant Development, BRIEF-P Behavior Rating Inventory of Executive Function