Relationship of iodine excess with thyroid function in 6-year-old children living in an iodine-replete area

Lee, Yun Jeong; Cho, Sun Wook; Lim, Youn‐Hee; Kim, Bung-Nyun; Kim, Johanna Inhyang; Hong, Yun-Chul; Park, Young Joo; Shin, Choong Ho; Lee, Young Ah

doi:10.3389/fendo.2023.1099824

Cited by 4 publications

(2 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Urine iodine concentration (UIC, μg/L) and urinary creatinine (Cr) levels were measured from spot morning urine samples collected within 3 days prior to thyroid US examination. Detailed methods of UIC and Cr measurements have been previously described ( 11 ). Iodine status was categorized as follows: iodine deficient (UIC: <100 μg/L), adequate (UIC: 100–299 μg/L), and excess (UIC: ≥ 300 μg/L) ( 15 ).…”

Section: Methodsmentioning

confidence: 99%

“…South Korea is an iodine-sufficient area ( 9 ), and a recent nationwide study reported an association between excess iodine and thyroid dysfunction in adolescents ( 10 ). In our previous study, we reported the effects of excess iodine on thyroid hormone levels in 6-year-old children ( 11 ). However, there is lack of evidence regarding the relationship between iodine status and thyroid US findings in healthy Korean children.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of iodine status on thyroid volume and goiter in children living in an iodine-replete area

Lee,

Choi,

Lim

et al. 2023

European Thyroid Journal

View full text Add to dashboard Cite

Objective Adequate iodine intake is essential for growing children, and thyroid volume (Tvol) is considered as an indicator of iodine status. We investigated Tvol and goiter using ultrasonography (US) and their association with iodine status in 228 6-year-old children living in Korea. Methods Iodine status was assessed using urine iodine concentration (UIC) and categorized as deficient (<100 μg/L), adequate (100–299 μg/L), mild excess (300–499 μg/L), moderate excess (500–999 μg/L), and severe excess (≥1000 μg/L). Tvol was measured using US, and a goiter on the US (goiter-US) was defined as Tvol greater than 97th percentile value by age- and body surface area (BSA)-specific international references. Results The median Tvol was 2.4 mL, larger than the international reference value (1.6 mL). The age- and BSA-specific goiter-US rates were 25.9% (n = 59) and 34.6% (n = 79), respectively. The prevalence of excess iodine was 73.7% (n = 168). As iodine status increased from adequate to severe excess, the goiter-US rate significantly increased (P for trend <0.05). The moderate and severe iodine excess groups showed higher risk of goiter-US (adjusted odds ratio (aOR) = 3.1 (95% CI: 1.1–9.2) and aOR = 3.1 (95% CI: 1.2–8.3), respectively; age-specific criteria) than the iodine-adequate group. Conclusions Excess iodine was prevalent in Korean children, and their Tvol was higher than the international reference values. Goiter rate was associated with iodine excess, which significantly increased in the moderate and severe iodine excess groups. Further studies are warranted to define optimal iodine intake in children.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of iodine status on thyroid volume and goiter in children living in an iodine-replete area

Lee,

Choi,

Lim

et al. 2023

European Thyroid Journal

View full text Add to dashboard Cite

show abstract

Pregnant women at risk for iodine deficiency but adequate iodine intake in school-aged children of Zhejiang Province, China

Zheng,

Yin,

Zhan

et al. 2024

Environ Geochem Health

View full text Add to dashboard Cite

The median urinary iodine concentration (UIC) of school-aged children has been commonly used as a surrogate to assess iodine status of a population including pregnant women. However, pregnant women have higher iodine requirements than children due to increased production of thyroid hormones. The aim of the study was to evaluate the iodine status of pregnant women and children as well as their household salt iodine concentration (SIC) in Quzhou, Zhejiang Province, China. Eligible pregnant women and children from all six counties of Quzhou in 2021 were recruited into the study. They were asked to complete a socio-demographic questionnaire and provide both a spot urine and a household table salt sample for the determination of UIC and SIC. A total of 629 pregnant women (mean age and gestation weeks of 29.6 years and 21.6 weeks, respectively) and 1273 school-aged children (mean age of 9 years and 49.8% of them were females) were included in the study. The overall median UIC of pregnant women and children in our sample was 127 (82, 193) μg/L and 222 (147, 327) μg/L, respectively, indicating sufficient iodine status in children but a risk of mild-to-moderate iodine deficiency in pregnant women. Distribution of iodine nutrition in children varied significantly according to their sex and age (P < 0.05). The rate of adequately household iodised salt samples (18–33 mg/kg) provided by pregnant women and children was 92.4% and 90.6%, respectively. In conclusion, our results indicated a risk of insufficient iodine status in pregnant population of China, but iodine sufficiency in school-aged children. Our data also suggested that median UIC of children may not be used as a surrogate to assess iodine status in pregnant women.

show abstract

Risks of Iodine Excess

Sohn,

Inoue,

Rhee

et al. 2024

Endocrine Reviews

View full text Add to dashboard Cite

Iodine is a micronutrient that is required for thyroid hormone synthesis. The iodide cycle in thyroid hormone synthesis consists of a series of transport, oxidation, organification, and binding/coupling steps in thyroid follicular cells. Common sources of iodine include the consumption of an iodine-rich diet or iodine-fortified foods, the administration of amiodarone, iodine-containing supplements, or iodinated contrast media, and other miscellaneous sources. Methods to assess population iodine status include the measurement of urinary iodine concentrations, blood thyroglobulin levels, prevalence of elevated neonatal thyrotropin levels, and thyroid volume. Although excessive iodine intake or exposure is generally well tolerated, an acute iodine load may result in thyroid dysfunction (hypothyroidism or hyperthyroidism) in certain susceptible individuals due to the failure to escape from the Wolff–Chaikoff effect and to the Jod–Basedow phenomenon, respectively. In this review, we discuss the associations between excessive iodine intake or exposure, with particular focus on iodinated contrast media as a common source of excess iodine in health care settings, and risks of incident thyroid dysfunction. We also summarize the risks of iodine excess in vulnerable populations and review current guidelines regarding the screening and monitoring of iodinated contrast–induced thyroid dysfunction. Finally, we discuss the long-term potential nonthyroidal health risks associated with iodine excess and suggest the need for more data to define safe upper limits for iodine intake, particularly in high-risk populations.

show abstract

Relationship of iodine excess with thyroid function in 6-year-old children living in an iodine-replete area

Cited by 4 publications

References 37 publications

Effects of iodine status on thyroid volume and goiter in children living in an iodine-replete area

Effects of iodine status on thyroid volume and goiter in children living in an iodine-replete area

Pregnant women at risk for iodine deficiency but adequate iodine intake in school-aged children of Zhejiang Province, China

Risks of Iodine Excess

Contact Info

Product

Resources

About