Iodine Deficiency in a Study Population of Norwegian Pregnant Women—Results from the Little in Norway Study (LiN)

Nutrients
Q1
Apr 2018
Citations:50
Influential Citations:4
Observational Studies (Human)
80
S2 IconPDF Icon

Enhanced Details

Methods
Cross-sectional population-based prospective cohort of pregnant Norwegian women (Little in Norway LiN); recruited from nine public health clinics across Norway; 16–34 weeks gestation; five data collection points up to age 18 months; 954 pregnant women included (age 17–43; median 30); data included spot urine samples and dietary data; study conducted 2011–2012.
Results
Median urinary iodine concentration (UIC) was 85 µg/L; 78.4% had UIC <150 µg/L; 23.2% ≤50 µg/L; 5.2% >250 µg/L. Frequent iodine supplement users had higher UIC (120 µg/L) than non-frequent users (75 µg/L). Milk/dairy intake of 4–9 portions/day yielded higher UIC (99 µg/L) than 0–1 portions/day (57 µg/L) or 2–3 portions/day (83 µg/L). Women in mid-Norway had the lowest UIC (72 µg/L). Conclusion: Diet alone did not secure a sufficient iodine intake in pregnancy; there is an urgent need for public health strategies to secure adequate iodine nutrition among pregnant women in Norway. Iodine supplementation and higher dairy intake are associated with better iodine status, underscoring a need for policy action (e.g., supplementation guidance and iodized salt considerations) to improve population-level iodine sufficiency.
Limitations
Not representative of the population’s socioeconomic background; most samples collected in the second trimester (limited first-trimester data); reliance on a single spot urine sample with day-to-day variability; potential misclassification when dichotomizing UIC and UI/Cr; seasonal/regional confounding; lack of national monitoring limits generalizability.

Abstract

Iodine sufficiency is particularly important in pregnancy, where median urinary iodine concentration (UIC) in the range of 150–250 µg/L indicates adequate iodine status. The aims of this study were to determine UIC and assess if dietary and maternal ...