The Standard, Intervention Measures and Health Risk for High Water Iodine Areas

Liu, Peng; Liu, Lixiang; Shen, Hongmei; Jia, Qi; Wang, Jinbiao; Zheng, Heming; Ma, Jing; Zhou, Dan; Liu, Shoujun; Su, Xiaohui

doi:10.1371/journal.pone.0089608

Cited by 24 publications

(13 citation statements)

References 12 publications

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“…High iodine contents in drinking water (higher than 100 μg/L) have been found to be scattered across Shanxi and Jiangsu [24][25][26]. These abovementioned studies have shown that the median UIC in the population is positively correlated with the iodine content in drinking water under the current USI program [29,30]. The median UIC for pregnant women increased from 197.7 μg/ L to 221.9 μg/L and to 452.1 μg/L when the iodine content in drinking water gradually increased from 3.0 μg/L to 57.5 μg/L and to 464.0 μg/L, respectively.…”

Section: Discussionmentioning

confidence: 92%

Geographical influences on the iodine status in pregnant women, neonates, and school-age children in China

Lou

Mao

Zhu

et al. 2020

Nutr J

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Background: Pregnant women, neonates, and school-age children are vulnerable to iodine deficiency. The iodine contents in the environment (drinking water and household salt for cooking) vary by geographical location in China. The aim of this study was to assess the iodine status in vulnerable groups from different geographical zones and analyze the iodine content in household salt and drinking water from these zones. Methods: In coastal and inland regions of Zhejiang Province, China, samples of spot urine, drinking water, and household salt for cooking from both pregnant women and school-age children were determined for iodine concentration between 2017 and 2018. Thyroid-stimulating hormone (TSH) levels from neonates born between 2014 and 2015 were acquired from the Newborns Screening Information System. The iodine status of the vulnerable populations was assessed according to the criteria recommended by the World Health Organization. Results: The median UIC of pregnant women was significantly lower in the coastal region (113.0 μg/L) than the inland region (134.9 μg/L; p < 0.001). The median UICs of pregnant women from these two regions were below the lower optimal iodine cutoff level of 150 μg/L. The percentage of neonates with elevated TSH (> 5 mIU/L) was significantly higher in the coastal region (15.8%) than the inland region (10.5%; p < 0.001). The percentage of neonates with elevated TSH from each region decreased within the range of mild iodine deficiency of 3-19.9%. The median UIC of the coastal school-age children was 156.0 μg/L, and the median UIC of inland children was 181.5 μg/ L. Both medians fell within the recommended optimal iodine range of 100-299 μg/L. The iodine concentrations in drinking water varied from 1.0 μg/L in the inland region to 2.0 μg/L in the coastal region. The proportion of households that consumed iodized salt was lower in the coastal region (nearly 65%) than the inland region (approximately 95%). Conclusions: In these two regions with low iodine contents in drinking water, both pregnant women and neonates were iodine-deficient, although school-age children were iodine-sufficient. Urgent efforts are needed to improve the iodine status of pregnant women and neonates.

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Section: Discussionmentioning

confidence: 92%

Geographical influences on the iodine status in pregnant women, neonates, and school-age children in China

Lou

Mao

Zhu

et al. 2020

Nutr J

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“…Since the implementation of mandatory universal salt iodization in 1996, China has eliminated iodine deficiency and become an iodine-sufficient country ( 24 ). Epidemiological studies also found that the resident's average serum TSH level has risen due to the effects of increased iodine intake ( 25 ). A similar epidemiological survey reported by Korea showed that there was high iodine intake in Korea, resulting in serum TSH exhibiting a right-shifted distribution in that population ( 26 ).…”

Section: Discussionmentioning

confidence: 99%

Gestational TSH and FT4 Reference Intervals in Chinese Women: A Systematic Review and Meta-Analysis

Gao

et al. 2018

Front. Endocrinol.

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Background: Serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) change dynamically during pregnancy. Differences in geographic regions, populations, and manufacturer's methodologies can affect the reference intervals for thyroid function tests. The 2017 guidelines of the American Thyroid Association (ATA) recommended 4.0 mU/L as the cut-off point for the upper limit of serum TSH in early pregnancy. A systematic review is called for to establish practical, gestational-specific TSH and FT4 reference intervals for pregnant Chinese women and to explore whether the criteria are suitable for China.Methods: English and Chinese articles published from inception to Aug 2017 were searched in the PubMed, EMBASE, and SCIE English-language databases and the CNKI, WanFang, and CQVIP Chinese databases. The relative descent or ascent rates of serum TSH and FT4 were calculated, after which Comprehensive Meta-Analysis V2.0 software was used to analyze the data.Results: Eleven studies (6 in English and 5 in Chinese), five kits and 11,629 Chinese women from nine cities were considered in this meta-analysis. Compared with the reference ranges provided by manufacturers, serum TSH decreased in the first trimester, with the upper limit declining by 21.7% (5.0–36.6%), to a value close to 4.0 mU/L, and the lower limit declining by 85.7% (73.5–97.1%). It continued decreasing in the second trimester, with the upper limit declining by 24.0% (6.4–40.9%) and the lower limit declining by 40.7% (9.0–85.7%). For FT4, the upper limit fluctuated slightly, and the lower limit increased by 6.8% (1.0–14.6%) in the first trimester. Serum FT4 dropped gradually, with the upper limit declining by 21.8% (2.5–31.8%) and the lower limit declining by 12.7% (2.6–19.6%) in the second trimester. During the third trimester, the upper limit decreased by 25.1% (12.7–35.0%), while the lower limit decreased by 20.9% (14.8–27.3%).Conclusions: Various regions, kits and test methods affect the gestational TSH and FT4 levels. The non-pregnant serum TSH upper limit minus 22% is very close to 4.0 mU/L, which can be used as a sub-optimal approach to represent the cut-off value for pregnant Chinese women in the first trimester.

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“…Meanwhile, previous studies suggest a goitrogenic effect of excess iodine in school-age children and adults [62] – [67] . In areas with high iodine content in the drinking water, school-age children had elevated median UIC and endemic goiter, suggesting that, in addition to adjusting the iodine content of salt, improving water quality is also necessary [62] , [63] . In a prospective study, 10 normal men accepted daily oral intake of excess iodine for 1 month.…”

Section: Discussionmentioning

confidence: 99%

Prevalence of Goiter and Thyroid Nodules before and after Implementation of the Universal Salt Iodization Program in Mainland China from 1985 to 2014: A Systematic Review and Meta-Analysis

et al. 2014

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ObjectivesWe comprehensively estimated the prevalence of goiter and thyroid nodules (TNs) before and after the implementation of the Universal Salt Iodization (USI) program in mainland China and provided information for creating effective health policies.MethodsPubMed, Google Scholar, CNKI, Chinese Wanfang and Chongqing VIP databases were searched for relevant studies from Jan 1985 to Feb 2014. Data from eligible citations were extracted by two independent reviewers. All analyses were performed with Stata 11.0 and SPSS 17.0.ResultsEligible articles (N = 31; 4 in English and 27 in Chinese) included 52 studies (15 about goiter rates made before 1996 and 14 afterwards, and 23 about TNs). Our meta-analysis suggests a pooled prevalence for goiter before and after 1996 and for TNs of 22.8% (95% CI: 15.3%, 30.3%), 12.6% (95% CI: 9.4%, 15.8%) and 22.7% (95% CI: 18.3%, 27.0%), respectively. Egger's test of three independent categories revealed no evidence of publication bias (p = 0.101, 0.148 and 0.113, respectively).ConclusionsThe prevalence of goiter was reduced by almost half after 1996 in mainland China, so the USI program was considered beneficial. However, subgroup analysis suggests that both insufficient and excess iodine may be associated with goiter. The prevalence of goiter and TNs increased significantly after 2002, suggesting a risk of excessive iodine intake. Thus, salt iodization standardizations should be set according to local conditions.

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The Standard, Intervention Measures and Health Risk for High Water Iodine Areas

Cited by 24 publications

References 12 publications

Geographical influences on the iodine status in pregnant women, neonates, and school-age children in China

Geographical influences on the iodine status in pregnant women, neonates, and school-age children in China

Gestational TSH and FT4 Reference Intervals in Chinese Women: A Systematic Review and Meta-Analysis

Prevalence of Goiter and Thyroid Nodules before and after Implementation of the Universal Salt Iodization Program in Mainland China from 1985 to 2014: A Systematic Review and Meta-Analysis

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