Hou Christy, Jack Michelle, Hobbs Annabelle, Ambler Geoffrey, Cho Yoon Hi
Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
Faculty of Health Sciences and Medicine, Bond University, Queensland, Australia.
Thyroid Res. 2025 Aug 7;18(1):40. doi: 10.1186/s13044-025-00256-5.
Iodine is essential to thyroid hormone production, and both excess and deficiency can cause thyroid dysfunction in infants. While urinary iodine concentration (UIC) is used to assess population iodine status, there is no gold standard for determining iodine status in individual infants. Our study aimed to examine the clinical use of UIC in the investigation of thyroid dysfunction in hospitalised infants.
We examined hospital records of infants (age < 24 months) admitted to The Children's Hospital at Westmead who had UIC collected in the context of thyroid dysfunction between 2007-2009 and 2017-2021, two time periods separated by changes in public health measures for iodine nutrition and local clinical practice.
Of 152 infants, 13.8% had UIC in iodine deficient range (WHO population-based definition: UIC < 100 µg/L) and 53.9% in iodine excess range (UIC ≥ 300 µg/L). Highest quartile UIC (> 1432 µg/L) was significantly associated with pre-test clinician suspicion of iodine excess, identification of source of iodine exposure, higher percentage of premature babies, and those with cardiac anomalies or who required surgery. Median free thyroxine (fT4) level was significantly lower in the highest UIC quartile group compared to the lower three quartiles (9.4pmol/L [interquartile range 7.8-vs 13.7] vs. 12.7 pmol/L [10.3-15.6]; p = 0.004). While median TSH was elevated in all UIC quartiles in this group, there were no significant differences in the levels between the UIC quartile groups.
Extremely high random UIC can be helpful to confirm clinical suspicion of iodine excess in hospital-based infants, taken in the context of thyroid dysfunction in critical illness. The degree of thyroid dysfunction associated with high UIC in this clinically complex and often premature patient population may be better measured by the fT4 level rather than the degree of TSH elevation.
碘对于甲状腺激素的产生至关重要，碘摄入过量和不足均可导致婴儿甲状腺功能障碍。虽然尿碘浓度（UIC）用于评估人群碘营养状况，但目前尚无确定个体婴儿碘营养状况的金标准。我们的研究旨在探讨UIC在住院婴儿甲状腺功能障碍调查中的临床应用价值。
我们查阅了悉尼韦斯特米德儿童医院2007 - 2009年及2017 - 2021年期间因甲状腺功能障碍而采集UIC的婴儿（年龄<24个月）的住院记录，这两个时间段因碘营养公共卫生措施及当地临床实践的变化而分隔。
在152例婴儿中，13.8%的婴儿UIC处于碘缺乏范围（世界卫生组织基于人群的定义：UIC<100μg/L），53.9%处于碘过量范围（UIC≥300μg/L）。UIC最高四分位数组（>1432μg/L）与临床医生在检测前怀疑碘过量、确定碘暴露源、早产婴儿比例较高以及患有心脏异常或需要手术的婴儿显著相关。最高UIC四分位数组的游离甲状腺素（fT4）中位数水平显著低于较低的三个四分位数组（9.4pmol/L[四分位间距7.8 - 13.7]vs.12.7pmol/L[10.3 - 15.6]；p = 0.004）。虽然该组所有UIC四分位数组的促甲状腺激素（TSH）中位数均升高，但各UIC四分位数组之间的水平无显著差异。
在危重症甲状腺功能障碍的背景下，极高的随机UIC有助于确诊住院婴儿碘过量的临床怀疑。在这个临床情况复杂且通常为早产的患者群体中，与高UIC相关的甲状腺功能障碍程度可能通过fT4水平而非TSH升高程度来更好地衡量。
