Iodine Nutrition in Children ≤2 years of Age in Norway.

BACKGROUND: As a component of the thyroid hormones (THs), iodine is vital for normal neurodevelopment during early life. However, both deficient and excess iodine may affect TH production, and data on iodine status in young children are scarce. OBJECTIVES: To describe iodine nutrition (iodine status and intake) in children ≤2 y of age in Innlandet County (Norway) and to describe the associations with maternal iodine nutrition. METHODS: A cross-sectional study was performed in a representative sample of mother-child pairs selected from 30 municipalities from November 2020 until October 2021. Iodine status [child urinary iodine concentration (UIC), maternal UIC, and breast milk iodine concentration (BMIC)] was measured. Child's iodine intake was estimated using 2 24-h dietary recalls (24-HR) and a food frequency questionnaire. The Multiple Source Method was used to estimate the usual iodine intake distributions from the 24-HR assessments. RESULTS: The median UIC in 333 children was 145 µg/L, indicating adequate iodine status according to the WHO cutoff (100 µg/L). The median usual iodine intake was 83 µg/d. Furthermore, 35% had suboptimal usual iodine intakes [below the proposed Estimated average requirement (72 µg/d)], whereas <1% had excessive usual iodine intakes [above the Upper intake level (200 µg/d)]. There was a positive correlation between children's iodine intake and BMIC (Spearman rank correlation coefficient r = 0.67, P < 0.001), and between children's UIC and BMIC (r = 0.43, P < 0.001), maternal UIC (r = 0.23, P = 0.001), and maternal iodine intake (r = 0.20, P = 0.004). CONCLUSION: Despite a median UIC above the cutoff for iodine sufficiency, more than a third of the children had suboptimal usual iodine intakes. Our findings suggest that many children will benefit from iodine fortification and that risk of iodine excess in this age group is low.

Trend analyses of persistent organic pollutants in human milk from first-time mothers in Norway between 2002 and 2021.

INTRODUCTION: Persistent organic pollutants (POPs) are stable compounds characterized by their resistance to degradation. From the 1960-70's organochlorine pesticides (OCPs), such as DDTs and polychlorinated biphenyls (PCBs) raised concerns regarding health and environmental impacts. This has led to the banning of POPs in the USA and Europe including Norway in 1980 and worldwide under the 2004 Stockholm Convention. The exposure of nursing infants to POPs has been a significant focus, prompting extensive research into the presence of these substances in human breast milk. In this study, we explored the temporal trends of POPs concentrations in breast milk sampled between 2002 and 2021 by comparing the concentration across the mother's year of birth. METHOD: Two Norwegian cohorts of lactating women were utilized (the HUMIS study and the "Iodine in Early Life"-Study). Concentrations of 15 different POPs, including PCBs, OCPs, and brominated diphenyl ethers (BDEs) were measured in 513 breast milk samples that had been collected over two decades in a subset of first-time mothers. RESULTS: Time trend analysis indicated a steady decrease in concentration levels when adjusted for maternal age. The largest reduction was observed in ß-HCH, age-adjusted (-17.1%, 95% CI -18.7, -15.4), followed by ∑6BDE (-9.1%, 95% CI -10.5, -7.7), ∑6PCBs (-7.1%, 95% CI -7.7, -6.5), and ∑2DDTs (-7.0%, 95% CI -8.0, -6.0). In contrast, an increasing trend was noted in the median concentrations of ß-HCH, ∑2DDTs, and ∑6BDE in the mothers born in 1990-1994 to 1995-2002. CONCLUSION: Our study demonstrates a decline of most POPs in breast milk, likely attributed to international regulatory efforts like the Stockholm Convention. Notably, an increase in the 95th percentile concentrations of ß-HCH, ∑2DDTs, and ∑6BDEs was noted in mothers born in 1990-1994 compared to those born in 1995-2002 suggests demographic shifts that may influence exposure levels. Further research is needed to explore and understand the underlying factors for the rise in median concentrations of ∑6BDEs.