Maternal iodine status during lactation and infant weight and length in Henan Province, China

Jin Yang,Zhe Wang,Heming Zheng,Yang Liu,Zongyu Hao,Lin Zhu,Xiaofeng Li

doi:10.1186/s12884-017-1569-0

Abstract

BackgroundInfants are very sensitive to iodine deficiency. Breastfed infants are dependent on maternal iodine intake. The aim of this study was to evaluate the relationship between maternal iodine status during lactation and infant weight and length.MethodsA cross-sectional survey was conducted to investigate maternal iodine status and infant anthropometric measures in Henan Province, China. Only exclusive breastfeeding mothers and their infants < 6 months of age (n = 747) were included in our final analysis. Urine samples were collected from all the mothers and infants. Infant weight and length were measured and converted into weight-for-age Z-score (WAZ) and height-for-age Z-score (HAZ) using the World Health Organization (WHO) AnthroPlus software.ResultsThe median urinary iodine concentration (UIC) in lactating women was significant lower than that in their infants (177.4 vs 261.1 μg/L, P < 0.001). A positive correlation was found between maternal and infant urinary iodine concentration (r = 0.203, P < 0.01). The mean HAZ and WAZ values were lowest in the infants whose mothers had UIC below 50 μg/L (n = 41). Infant WAZ with maternal UIC below 50 μg/L was significantly lower than those with maternal UIC of 50 μg/L or above (P = 0.043). After adjusting for confounding factors, there were significant differences in infant WAZ between maternal UIC groups.ConclusionsThe present study suggests that maternal iodine status during lactation may be related to their infant anthropometric index. Appropriate iodine intake of lactating women is beneficial for their infants.

Highlights

Infants are very sensitive to iodine deficiency
The objective of the present study was to assess the relationship between maternal iodine status and infant anthropometric index
Some studies found that the median urinary iodine concentration (UIC) in lactating women might be less than that in pregnant women, which was partly due to the iodine loss into breast milk and the normalization of thyroid hormone production [22,23,24,25,26]

Summary

Introduction

Infants are very sensitive to iodine deficiency. Breastfed infants are dependent on maternal iodine intake. The aim of this study was to evaluate the relationship between maternal iodine status during lactation and infant weight and length. Infants are very sensitive to iodine deficiency because of their high demands and low storages of iodine [1, 2]. The first 2 years of age is a crucial time for neurological development and growth. Even mild iodine deficiency may lead to irreversible damage during this period, such as low intelligence, neonatal hypothyroidism, short stature, skeleton disorders, and other growth retardation [2, 3]. It is well known that iodine is an essential material in synthesis of thyroid hormones (TH) [1, 3].

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Conclusion