Low urinary iodine excretion during early pregnancy is associated with alterations in executive functioning in children.
The rare but deleterious effects of severe iodine deficiency during pregnancy on cognitive functioning of children are well known. Reports on possible associations between mild-to-moderate maternal iodine deficiency and child development, however, are scarce. In a population-based cohort we examined the association between maternal urinary iodine during early pregnancy and executive functioning in children at 4 y of age. In addition, we investigated the modification of this association by maternal diet and thyroid function. During pregnancy, we measured urinary iodine and thyroid hormone concentrations in 1156 women. In 692 of their children impairment of executive functioning was assessed by the Behavior Rating Inventory of Executive Function. Five hundred mothers of Dutch national origin completed an FFQ. Analyses were performed by using regression models. The children of mothers with low urinary iodine showed higher scores on the problem scales of inhibition [β = 0.05 (95% CI: 0.01, 0.10), P = 0.03] and working memory [β = 0.07 (95% CI: 0.02, 0.12), P = 0.003]. Although maternal dietary intake and thyroid hormone concentration did not significantly modify these associations, the associations between urinary iodine and problems of inhibition were attenuated after adjustment for maternal psychological symptoms. In addition, the consumption of bread [β = 0.61 (95% CI: 0.27, 0.95), P < 0.001] and eggs (β = 1.87 (95% CI: 0.13, 3.62), P = 0.04] was associated with higher urinary iodine. Thus, low maternal urinary iodine during pregnancy is associated with impaired executive functioning in children. Because these symptoms were subclinical and occurred at an early age, future studies are needed to show whether these children are more vulnerable to develop later clinical disorders.
The Generation R Study Group, Erasmus MC, University Medical Centre, Rotterdam, The Netherlands.
Nina H
NH
van Mil
Henning
H
Tiemeier
Jacoba J
JJ
Bongers-Schokking
Akhgar
A
Ghassabian
Albert
A
Hofman
Herbert
H
Hooijkaas
Vincent W V
VW
Jaddoe
Sabine M
SM
de Muinck Keizer-Schrama
Eric A P
EA
Steegers
Theo J
TJ
Visser
Willy
W
Visser
H Alec
HA
Ross
Frank C
FC
Verhulst
Yolanda B
YB
de Rijke
Régine P M
RP
Steegers-Theunissen
D000328:Adult; D002675:Child, Preschool; D056344:Executive Function; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007455:Iodine / Q000008:administration & dosage / Q000172:deficiency / Q000652:urine*; D008297:Male; D011247:Pregnancy / Q000652:urine*
D007455:Iodine