scholarly journals Letter to the Editor: “Association of Maternal Iodine Status With Child IQ: A Meta-Analysis of Individual-Participant Data”

2019 ◽  
Vol 104 (12) ◽  
pp. 6116-6117
Author(s):  
Shoshana Sztal-Mazer
Keyword(s):  
Meta Analysis ◽  
Individual Participant Data ◽  
Iodine Status ◽  
Letter To The Editor ◽  
Individual Participant

scholarly journals Response to Letter to the Editor: “Association of Maternal Iodine Status With Child IQ: A Meta-Analysis of Individual Participant Data”

2020 ◽  
Vol 105 (9) ◽  
pp. e3505-e3506
Author(s):  
Deborah Levie ◽  
Sarah C Bath ◽  
Mariana Dineva ◽  
Henning Tiemeier ◽  
Margaret P Rayman ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Individual Participant Data ◽  
Iodine Status ◽  
Letter To The Editor ◽  
Individual Participant

scholarly journals Association of Maternal Iodine Status With Child IQ: A Meta-Analysis of Individual Participant Data

2019 ◽  
Vol 104 (12) ◽  
pp. 5957-5967 ◽  
Author(s):  
Deborah Levie ◽  
Tim I M Korevaar ◽  
Sarah C Bath ◽  
Mario Murcia ◽  
Mariana Dineva ◽  
...  
Keyword(s):  
Iodine Deficiency ◽  
Meta Analysis ◽  
Urinary Iodine ◽  
First Trimester ◽  
Individual Participant Data ◽  
Verbal Iq ◽  
Iodine Status ◽  
Child Neurodevelopment ◽  
Individual Participant ◽  
In Pregnancy

Abstract Context Although the consequences of severe iodine deficiency are beyond doubt, the effects of mild to moderate iodine deficiency in pregnancy on child neurodevelopment are less well established. Objective To study the association between maternal iodine status during pregnancy and child IQ and identify vulnerable time windows of exposure to suboptimal iodine availability. Design Meta-analysis of individual participant data from three prospective population-based birth cohorts: Generation R (Netherlands), INMA (Spain), and ALSPAC (United Kingdom); pregnant women were enrolled between 2002 and 2006, 2003 and 2008, and 1990 and 1992, respectively. Setting General community. Participants 6180 mother-child pairs with measures of urinary iodine and creatinine concentrations in pregnancy and child IQ. Exclusion criteria were multiple pregnancies, fertility treatment, medication affecting the thyroid, and preexisting thyroid disease. Main Outcome Measure Child nonverbal and verbal IQ assessed at 1.5 to 8 years of age. Results There was a positive curvilinear association of urinary iodine/creatinine ratio (UI/Creat) with mean verbal IQ only. UI/Creat <150 µg/g was not associated with lower nonverbal IQ (−0.6 point; 95% CI: −1.7 to 0.4 points; P = 0.246) or lower verbal IQ (−0.6 point; 95% CI: −1.3 to 0.1 points; P = 0.082). Stratified analyses showed that the association of UI/Creat with verbal IQ was only present up to 14 weeks of gestation. Conclusions Fetal brain development is vulnerable to mild to moderate iodine deficiency, particularly in the first trimester. Our results show that potential randomized controlled trials investigating the effect of iodine supplementation in women with mild to moderate iodine deficiency on child neurodevelopment should begin supplementation not later than the first trimester.

scholarly journals Thyroid Function in Early Pregnancy, Child IQ, and Autistic Traits: A Meta-Analysis of Individual Participant Data

2018 ◽  
Vol 103 (8) ◽  
pp. 2967-2979 ◽  
Author(s):  
Deborah Levie ◽  
Tim I M Korevaar ◽  
Sarah C Bath ◽  
Albert Dalmau-Bueno ◽  
Mario Murcia ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Early Pregnancy ◽  
Meta Analysis ◽  
Autistic Traits ◽  
Individual Participant Data ◽  
Thyroid State ◽  
Verbal Iq ◽  
Iodine Status ◽  
Child Neurodevelopment ◽  
Individual Participant

Abstract Context Low maternal free T4 (FT4) has been associated with poor child neurodevelopment in some single-center studies. Evidence remains scarce for the potential adverse effects of high FT4 and whether associations differ in countries with different iodine status. Objective To assess the association of maternal thyroid function in early pregnancy with child neurodevelopment in countries with a different iodine status. Design, Setting, and Participants Meta-analysis of individual participant data from 9036 mother–child pairs from three prospective population-based birth cohorts: INMA [Infancia y Medio Ambiente (Environment and Childhood project) (Spain)], Generation R (Netherlands), and ALSPAC (Avon Longitudinal Study of Parents and Children, United Kingdom). The exclusion criteria were multiple pregnancies, fertility treatments, thyroid-interfering medication usage, and known thyroid disease. Main Outcomes Child nonverbal IQ at 5 to 8 years of age, verbal IQ at 1.5 to 8 years of age, and autistic traits within the clinical range at 5 to 8 years of age. Results FT4 &lt;2.5th percentile was associated with a 3.9-point (95% CI, −5.7 to −2.2) lower nonverbal IQ and a 2.1-point (95% CI, −4.0 to −0.1) lower verbal IQ. A suggestive association of hypothyroxinemia with a greater risk of autistic traits was observed. FT4 &gt;97.5th percentile was associated with a 1.9-fold (95% CI, 1.0 to 3.4) greater risk of autistic traits. No independent associations were found with TSH. Conclusions Low maternal FT4 was consistently associated with a lower IQ across the cohorts. Further studies are needed to replicate the findings of autistic traits and investigate the potential modifying role of maternal iodine status. FT4 seems a reliable marker of fetal thyroid state in early pregnancy, regardless of the type of immunoassay.

scholarly journals Association of maternal iodine status with child IQ: a meta-analysis of individual-participant data

2019 ◽  
Author(s):  
Levie D ◽  
Korevaar TIM ◽  
Bath SC ◽  
Murcia M ◽  
Dineva M ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Individual Participant Data ◽  
Iodine Status ◽  
Individual Participant
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