Serum Iodine Is Correlated with Iodine Intake and Thyroid Function in School-Age Children from a Sufficient-to-Excessive Iodine Intake Area

ABSTRACT Background An alternative feasible and convenient method of assessing iodine intake is needed. Objective The aim of this study was to examine the utility of serum iodine for assessing iodine intake in children. Methods One blood sample and 2 repeated 24-h urine samples (1-mo interval) were collected from school-age children in Shandong, China. Serum free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), thyroglobulin (Tg), total iodine (StI), and non-protein-bound iodine (SnbI) concentrations and urine iodine (UIC) and creatinine (UCr) concentrations were measured. Iodine intake was estimated based on two 24-h urine iodine excretions (24-h UIE). Associations between serum iodine and other factors were analyzed using the Spearman rank correlation test. Receiver operating characteristic (ROC) curves were used to illustrate diagnostic ability of StI and SnbI. Results In total, 1686 children aged 7–14 y were enrolled. The median 24-h UIC for the 2 collections was 385 and 399 μg/L, respectively. The median iodine intake was estimated to be 299 μg/d and was significantly higher in boys than in girls (316 μg/d compared with 283 μg/d; P < 0.001). StI and SnbI were both positively correlated with FT4 (ρ = 0.30, P < 0.001; and ρ = 0.21, P < 0.001), Tg (ρ = 0.21, P < 0.001; and ρ = 0.19, P < 0.001), 24-h UIC (ρ = 0.56, P < 0.001; and ρ = 0.47, P < 0.001), 24-h UIE (ρ = 0.46, P < 0.001; and ρ = 0.49, P < 0.001), urine iodine-to-creatinine ratio (ρ = 0.58, P < 0.001; and ρ = 0.62, P < 0.001), and iodine intake (ρ = 0.49, P < 0.001; and ρ = 0.53, P < 0.001). The areas under the ROC curves for StI and SnbI for the diagnosis of excessive iodine intake in children were 0.76 and 0.77, respectively. The optimal StI and SnbI threshold values for defining iodine excess in children were 101 and 56.2 μg/L, respectively. Conclusions Serum iodine was positively correlated with iodine intake and the serum FT4 concentration in children. It is a potential biomarker for diagnosing excessive iodine intake in children. This trial was registered at clinicaltrials.gov as NCT02915536.

Download Full-text

Assessment of Dietary Iodine Intake in School Age Children: The Cross-Sectional ANIVA Study

Nutrients ◽

10.3390/nu10121884 ◽

2018 ◽

Vol 10 (12) ◽

pp. 1884 ◽

Cited By ~ 1

Author(s):

María Morales-Suárez-Varela ◽

Isabel Peraita-Costa ◽

Agustín Llopis-Morales ◽

Agustín Llopis-Gonzalez

Keyword(s):

Thyroid Hormones ◽

Iodine Deficiency ◽

Dairy Products ◽

Iodine Intake ◽

School Age Children ◽

School Age ◽

Nutritional Adequacy ◽

Cross Sectional ◽

The World ◽

Important Health

Iodine deficiency is one of the most important health problems in the world. It intervenes in the synthesis of thyroid hormones, which carry out important functions, so that a deficit of this mineral causes alterations of different kinds such as those related to growth. The objective of the present study was to know the prevalence of iodine deficit in the diet of Valencian children from 6 to 8 years old and their relationship with anthropometry. The analysis of the dietary intake was carried out through questionnaires. Thirteen schools participated in the study. The sample studied consists of 661 school children belonging to the Valencian Community, between 6 and 8 years of age: 298 boys and 363 girls. 79.12% of the children did not meet recommended daily iodine intakes. When comparing the groups of girls and boys with an inadequate intake, in general, girls show worse nutritional adequacy. When comparing the groups of girls and boys with sufficient iodine intake, no statistically significant differences were observed. No immediate effects of iodine deficiency on children’s anthropometry were observed. Intake of dairy products, fish and iodized salt is recommended, since they can contribute to the diet the iodine required to avoid a deficiency.

Download Full-text

Influence of excessive iodine intake on the thyroid function and spectrum of thyroid abnormalities in population of Turinsk, Sverdlovsk Region, of Russia

Clinical and experimental thyroidology ◽

10.14341/ket2015143-49 ◽

2015 ◽

Vol 11 (1) ◽

pp. 43 ◽

Cited By ~ 2

Author(s):

Aleksey Vasil'evich Kiyaev ◽

Nadezhda Mikhailovna Platonova ◽

Fatima Magomedovna Abdulhabirova ◽

Ekaterina Anatolyevna Troshina ◽

Grigoriy Anatol'evich Gerasimov

Keyword(s):

Thyroid Function ◽

Iodine Intake ◽

Excessive Iodine ◽

Thyroid Abnormalities ◽

Excessive Iodine Intake

Download Full-text

Excessive Iodine Intake and Subclinical Hypothyroidism in Children and Adolescents Aged 6–19 Years: Results of the Sixth Korean National Health and Nutrition Examination Survey, 2013–2015

Thyroid ◽

10.1089/thy.2017.0507 ◽

2018 ◽

Vol 28 (6) ◽

pp. 773-779 ◽

Cited By ~ 8

Author(s):

Min Jae Kang ◽

Il Tae Hwang ◽

Hye Rim Chung

Keyword(s):

Children And Adolescents ◽

National Health ◽

Subclinical Hypothyroidism ◽

Iodine Intake ◽

Nutrition Examination Survey ◽

Health And Nutrition ◽

Excessive Iodine ◽

Excessive Iodine Intake

Download Full-text

Study on the Urine Iodine Detection Results of School-age Children and Pregnant Women in Wudu District of Longnan City

10.47939/mh.v2i9.313 ◽

2021 ◽

Keyword(s):

Pregnant Women ◽

School Age Children ◽

School Age ◽

Urine Iodine

Download Full-text

#5 Excessive iodine intake during late pregnancy

Reproductive Toxicology ◽

10.1016/j.reprotox.2019.05.016 ◽

2019 ◽

Vol 88 ◽

pp. 134-135 ◽

Cited By ~ 1

Author(s):

Maria Ellfolk ◽

Maija-Riitta Orden ◽

Ulla Sankilampi ◽

Heli Malm

Keyword(s):

Late Pregnancy ◽

Iodine Intake ◽

Excessive Iodine ◽

Excessive Iodine Intake

Download Full-text

Chronic iodine excess does not increase the incidence of hyperthyroidism: a prospective community-based epidemiological survey in China

Acta Endocrinologica ◽

10.1530/eje-06-0651 ◽

2007 ◽

Vol 156 (4) ◽

pp. 403-408 ◽

Cited By ~ 27

Author(s):

Fan Yang ◽

Zhongyan Shan ◽

Xiaochun Teng ◽

Yushu Li ◽

Haixia Guan ◽

...

Keyword(s):

Urinary Iodine ◽

Iodine Intake ◽

Urinary Iodine Excretion ◽

Thyroid Peroxidase ◽

Community Based ◽

Iodine Excess ◽

Iodine Supplementation ◽

Excessive Iodine ◽

Iodine Excretion ◽

Excessive Iodine Intake

Objective: An increasing incidence of hyperthyroidism has been observed when iodine supplementation has been introduced to an iodine-deficient population. Moreover, the influence of chronic more than adequate or excessive iodine intake on the epidemiological features of hyperthyroidism has not been widely and thoroughly described. To investigate the influences of different iodine intake levels on the incidence of hyperthyroidism, we conducted a prospective community-based survey in three communities with mild-deficient, more than adequate (previously mild deficient iodine intake), and excessive iodine intake. Subjects and methods: In three rural Chinese communities, a total of 3761 unselected inhabitants aged above 13 years participated in the original investigation and 3018 of them received identical examinations after 5 years. Thyroid function, levels of thyroid peroxidase antibody (TPOAb), thyroglobulin antibody and urinary iodine excretion were measured and thyroid ultrasound examination was also performed. Results: In three communities, median urinary iodine excretion was 88, 214, and 634 μg/l (P<0.05) respectively. The cumulative incidence of hyperthyroidism was 1.4, 0.9, and 0.8% (P>0.05) respectively. Autoimmune hyperthyroidism was predominant in thyroid hyperfunction in all the three cohorts. Either positive TPOAb (>50 U/ml) or goiter in original healthy participants was associated with the occurrence of unsuspected hyperthyroidism in 5 years (logistic regression, OR=4.2 (95% CI 1.7–8.8) for positive TPOAb, OR=3.1 (95% CI 1.4–6.8) for goiter). Conclusion: Iodine supplementation may not induce an increase in hyperthyroidism in a previously mildly iodine-deficient population. Chronic iodine excess does not apparently increase the risk of autoimmune hyperthyroidism, suggesting that excessive iodine intake may not be an environmental factor involved in the occurrence of autoimmune hyperthyroidism.

Download Full-text