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