Iodine status of teenage girls on the island of Ireland

Karen Mullan*, Lesley Hamill, Katy Doolan, Ian Young, Peter Smyth, Albert Flynn, Janette Walton, Andrew A. Meharg, Manus Carey, Claire McKernan, Marcia Bell, Neil Black, Una Graham, David McCance, Cathy McHugh, Paul McMullan, Siobhan McQuaid, Aonghus O’Loughlin, Antoinette Tuthill, Sarah C. BathMargaret Rayman, Jayne V. Woodside

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)
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Purpose: The trace element iodine is a vital constituent of thyroid hormones. Iodine requirements increase during pregnancy, when even mild deficiency may affect the neurocognitive development of the offspring. Urinary iodine concentration (UIC) is the means of assessing iodine status in population surveys; a median UIC of 100–199 µg/L is deemed sufficient in a non-pregnant population. Milk is the main dietary source of iodine in the UK and Ireland. Methods: We surveyed the iodine status of 903 girls aged 14–15 years in seven sites across the island of Ireland. Urine iodine concentration was measured in spot-urine samples collected between March 2014 and October 2015. Food group intake was estimated from iodine-specific food-frequency questionnaire. Milk-iodine concentration was measured at each site in summer and winter. Results: The median UIC overall was 111 µg/L. Galway was the only site in the deficient range (median UIC 98 µg/L). All five of the Republic of Ireland sites had UIC ≤ 105 µg/L. In the two sites surveyed twice, UIC was lower in summer vs winter months [117 µg/L (IQR 76–165) vs 130 µg/L (IQR 91–194) (p < 0.01)]. Milk samples collected from Galway and Roscommon had a lower mean iodine concentration than those from Derry/Londonderry (p < 0.05). Milk intake was positively associated with UIC (p < 0.001). Conclusions: This is the largest survey of its kind on the island of Ireland, which currently has no iodine-fortification programme. Overall, the results suggest that this young female population sits at the low end of sufficiency, which has implications if, in future, they enter pregnancy with borderline status.

Original languageEnglish
Number of pages9
JournalEuropean Journal of Nutrition
Early online date18 Jul 2019
Publication statusEarly online date - 18 Jul 2019


  • Iodine
  • Ireland
  • Nutrition
  • Teenagers

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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