Median Urinary Iodine Concentration Of Children Research Articles

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

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.

Spatial-Temporal Analysis of Factors Influencing the Median Urine Iodine Concentration of 8-10-year-old Children in Xinjiang, China 25 Years after Implementation of the Salt Iodization Policy.

The iodine status of children has improved and stabilized since China implemented salt iodization measures 25years ago, but routine monitoring of iodine cannot reflect regional factors that influence the iodine level in children. Therefore, we conducted a regional spatial-temporal analysis of children's median urinary iodine concentration (MUIC) and searched for possible factors that might affect children's iodine levels by mining monitoring data. We analyzed data from Xinjiang collected as part of the "Iodine Deficiency Disease National Monitoring Program" from 2017 to 2020. The study population consisted of 76,268 children who participated in the study. We used global autocorrelation analysis to determine whether the MUIC of children was spatially clustered, local autocorrelation analysis to identify specific clustering areas, local cold and hot spot analysis to verify the reliability of the local autocorrelation results, and a spatial lag model to identify factors affecting the children's MUIC. The MUIC values were 217.70, 227.00, 230.67, and 230.67µg/L in 2017, 2018, 2019, and 2020, respectively. Global autocorrelation analysis showed that the MUIC of all children in the study was significantly related to region (Z scores all > 1.96, P values all < 0.05) from 2017 to 2020. Partial auto-correlation analysis showed that counties with clusters of high values were mostly concentrated in the southwestern region of Xinjiang, whereas counties with clusters of low values were located in the northern part of Xinjiang. Partial cold spot and hot spot analysis showed the same trend, and there are more overlapping districts and counties in 4years. Three-dimensional trend analysis indicated that children from the western part of Xinjiang had high levels of urinary iodine. According to spatial lag model, urine iodine concentration level is positively correlated with thyroid volume, average salary, and urbanization rate classification. The MUIC of 8-10-year-old children in Xinjiang was spatially clustered and related to geographic region. Our results show that spatial analysis of survey data combined with geographic technology and public health data can accurately identify areas with abnormal iodine concentrations in children. Additionally, understanding the factors that influence iodine levels in the human population is conducive to improving monitoring methods.

Iodized salt consumption and iodine deficiency status in China: a cross-sectional study

Abstract Objective: To monitor iodized salt consumption and evaluate iodine deficiency status in 2014 in China. Materials and Methods: In 2014, a nationwide cross-sectional survey was conducted in 31 provinces (in this study, provinces, autonomous regions and municipalities in Mainland China were named as provinces). Probability proportional to size sampling method was adopted to recruit children ages 8–10 and pregnant women. 47,467 children’s and 18,994 pregnant women’s urine samples were collected and 47,706 children’s thyroid volumes were examined. Iodine content in salt was determined with 46,900 edible salt samples from children’s households; urinary iodine concentration (UIC) was tested from children and pregnant women’s urine samples; thyroid volume of children was assessed by ultrasound. Results: The national coverage rate of iodized salt and consumption rate of qualified iodized salt were 96.3% and 91.5%, respectively. Median iodine content in iodized salt was 25.2 mg/kg. In 22 of 31 provinces, the provincial coverage rates of iodized salt were over 95%. And consumption rates of qualified iodized salt were more than 90% in 21 provinces. In this study, the national median urinary iodine concentration (MUIC) of children in China was 197.9 μg/L. At the provincial level, MUIC of children in 19 provinces was 100–199 μg/L, which in 12 provinces was 200–299 μg/L. The national MUIC of pregnant women in 2014 was 154.6 μg/L, slightly higher than the lower limit of the WHO criteria for adequate (150–249 μg/L). At the provincial level, MUIC of pregnant women in 18 provinces was 100–149 μg/L, which in 13 provinces was 150–249 μg/L. The national prevalence of goiter among children in 2014 was 2.6%, of which only Shandong province (5.6%) exceeded the national standard (5%). Conclusions: In China, iodine deficiency disorders (IDD) has been eliminated since 2005. And in 2014, the IDD-free status still remained.

Fortification of Bread with Iodized Salt Corrected Iodine Deficiency in School-Aged Children, But Not in Their Mothers: A National Cross-Sectional Survey in Belgium

In the years 1985-1998, it was noted that mild iodine deficiency (MID) was a public health problem in Belgium. Therefore, an agreement was signed in 2009 between the bakery sector and the Ministry of Health, to fortify bread with iodized salt. We tested the hypothesis that the iodine status of Belgian children improved after the introduction of bread fortified with iodized salt. Since the dietary habits of children and adults may differ, we also investigated whether the median urinary iodine concentration (UIC) among the children in this study reflected the iodine status of their mothers. The study was cross-sectional. In a van, equipped with an ultrasound device, the thyroid volumes (Tvol) of children were measured and household salt samples and urine samples were collected from the children and their mothers. From across Belgium, 60 schools were selected and 1541 children participated in the study. The median UIC in children was 113.1 and 84.4 μg/L among their mothers. The median UIC among children was substantially greater compared to more than 10 years ago (80 μg/L; p<0.001). The median UIC in school-aged children was lower in Wallonia than in Flanders (p<0.001) and was higher in boys than in girls (p<0.001). The percentage of children with goiter was 7.2%. Of the 904 salt samples received, 63.2% did not contain iodine. Fortification of bread with iodized salt corrected iodine deficiency in Belgian children, but not in their mothers. To provide these women with an adequate iodine intake, the use of both iodized salt in bread and iodized instead of noniodized household salt needs to increase. Our findings suggest that the median UIC in children may not be an adequate surrogate of adults' iodine status. Therefore, monitoring iodine status should not be limited to children, but should be extended to women of child-bearing age.