Iodine supplementation of lactating women and assessment of infant visual information processing and maternal and infant thyroid function: A randomized trial.

Tafere Gebreegziabher,David G Thomas,Tay S Kennedy,Barbara J Stoecker,Tesfaye Woltamo,Seth Adu-Afarwuah

doi:10.1371/journal.pone.0223348

Tafere Gebreegziabher, David G Thomas + Show 4 more

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https://doi.org/10.1371/journal.pone.0223348

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Abstract

Iodine deficiency is one of the major causes of brain damage in childhood. However, iodine supplementation during early pregnancy and lactation can prevent the ill effects of iodine deficiency. This study evaluated maternal and infant thyroid function and infant visual information processing (VIP) in the context of maternal iodine supplementation. A community-based, randomized, supplementation trial was conducted. Mother infant dyads (n = 106) were enrolled within the first 10 days after delivery to participate in this study. Mothers were randomly assigned either to receive a potassium iodide capsule (225 μg iodine) daily for 26 weeks or iodized salt weekly for 26 weeks. Maternal thyroxine (T4), triiodothyronine (T3), thyroid stimulating hormone (TSH), thyroglobulin (Tg), urinary iodine concentration (UIC), breast milk iodine concentration (BMIC) and infant T4, TSH, UIC and VIP were measured as outcome variables. At baseline, neither mothers nor infants in the two groups were significantly different in any of the biomarkers or anthropometric measurements. Maternal TSH and goiter prevalence significantly decreased following iodine supplementation. The percentage of infants who preferentially remembered the familiar face was 26% in the capsule and 51% in the I-salt groups. Infant sex, length for age Z score, BMIC, maternal education and household food security were strong predictors of novelty quotient. In conclusion supplementation daily for six months with an iodine capsule or the use of appropriately iodized salt for an equivalent time was sufficient to reduce goiter and TSH in lactating women. Higher BMIC and LAZ as well as better household food security, maternal education, and male sex predicted higher novelty quotient scores in the VIP paradigm.

Highlights

Iodine is essential for the synthesis of thyroid hormones that regulate the metabolic processes of most cells and play important roles in human growth and development [1]
In places where iodized salt is not accessible, the recommendation from WHO/UNICEF/ICCIDD has been a daily dose of 250 μg iodine supplement for pregnant and lactating women or a single annual dose of 400 mg iodine as an iodized oil supplement [4]
Three mother-infant pairs were lost from the capsule group because of moving to other places and two mother-infant pairs were lost from the iodized salt (I-salt) group because of problems during testing

Summary

Introduction

Iodine is essential for the synthesis of thyroid hormones that regulate the metabolic processes of most cells and play important roles in human growth and development [1]. Iodine deficiency disorders (IDDs) are a major global public health problem and one of the most severe causes of preventable brain damage in childhood [2]. Iodized salt is a safe, cost effective and sustainable strategy to ensure sufficient intake of iodine by all individuals and to improve maternal and infant health [3,4,5,6]. In places where iodized salt is not accessible, the recommendation from WHO/UNICEF/ICCIDD has been a daily dose of 250 μg iodine supplement for pregnant and lactating women or a single annual dose of 400 mg iodine as an iodized oil supplement [4]. For children below 2 years of age, the recommendation is a daily dose of 90 μg iodine or a single annual dose of 200 mg iodine as an iodized oil supplement [4]. For infants 0 to 6 months of age, because a significant amount of iodine is secreted into breast milk, iodine should be available through breast milk, provided that the lactating mother is receiving sufficient iodine and her child is exclusively breastfed [9]

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