Adequate Urinary Iodine Concentration among Infants in the Inland Area of Norway.

Kjersti Sletten Bakken,Sigrun Henjum,Synne Groufh-Jacobsen,Tor Arne Strand,Beate Stokke Solvik,Tonje Eiane Aarsland,Elin Lovise Folven Gjengedal

doi:10.3390/nu13061826

Abstract

Considering the importance of iodine to support optimal growth and neurological development of the brain and central nervous system, this study aimed to assess and evaluate iodine status in Norwegian infants. We collected data on dietary intake of iodine, iodine knowledge in mothers, and assessed iodine concentration in mother’s breast milk and in infant’s urine in a cross-sectional study at two public healthcare clinics in the inland area of Norway. In the 130 mother–infant pairs, the estimated infant 24-h median iodine intake was 50 (IQR 31, 78) µg/day. The median infant urinary iodine concentration (UIC) was 146 (IQR 93, 250) µg/L and within the recommended median defined by the World Health Organization for this age group. Weaned infants had a higher UIC [210 (IQR 130, 330) µg/L] than exclusively breastfed infants [130 (IQR 78, 210) µg/L] and partially breastfed infants [135 (IQR 89, 250) µg/L], which suggest that the dietary data obtained in this study did not capture the accurate iodine intake of the included infants. The iodine status of infants in the inland area of Norway seemed adequate. Weaned infants had higher UIC compared to breastfed infants, suggesting early access and consumption of other sources of iodine in addition to breast milk.

Highlights

Iodine is an essential mineral required for the synthesis of thyroid hormones (THs)
We found that the median urinary iodine concentration (UIC) (146 μg/L) was indicative of sufficient iodine status according to the current World Health Organization (WHO) median of 100 μg/L in children under two years of age [14]
We found that the median UIC (146 μg/L) was indicativeof sufficient iodine status according toto the current median of of μg/L

Summary

Introduction

Iodine is an essential mineral required for the synthesis of thyroid hormones (THs). In the first phases of life, optimal levels of THs are critical for normal growth and neurological development of the brain and central nervous system [1]. Iodine excess may result in thyroid dysfunction, but the evidence for health effects of excess is more limited than of deficiency [2]. A systematic review from 2013 on the effect of ID on mental development in children 5 years and younger showed that even mild ID could influence school performance, intellectual ability, and work capacity of children [4]. A recent review concluded that there is insufficient evidence to support recommendations for iodine supplementation in areas of mild- or moderate deficiency of iodine [5]. Despite the role of iodine in growth and development, we have little knowledge of infant’s iodine status in Norway

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Discussion

Conclusion