A Comparative Study of Iodized Salt Programs: Shanghai and Switzerland
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Both Shanghai and Switzerland are developed regions with long-standing salt iodization programs and periodic monitoring. However, the two regions have their own approach to the implementation of the iodized salt policy. In Shanghai, monitoring was carried out every few years, using probability-proportional-to-size sampling technique to select 30 sampling units. Each unit consisted of more than 12 pregnant women and one randomly selected primary school. Urine samples were then taken from the chosen pregnant women and randomly recruited students of that school for iodine test. Data of Switzerland used in this comparative study was extracted from published researches. In Shanghai, the median urinary iodine concentration (UIC) in 2014 was 20% lower than in 1999 (P < 0.05). The median UIC of pregnant women in 2014 was 9.5% lower than that in 2011 (P < 0.05). In terms of iodized salt concentration, opposite to the increasing in Switzerland, it has exhibited a downward trend in Shanghai (P < 0.05). For the years monitored, the iodized salt concentration in Shanghai was significantly (P < 0.05) higher than in Switzerland. Though the UIC of children exhibited a downward trend in Shanghai (P < 0.05), it was still significantly (P < 0.05) higher than in Switzerland over the same monitoring period. However, the UIC in pregnant women was a totally different story, which was significantly (P < 0.05) lower in Shanghai than in Switzerland. Iodized salt is very important for maintaining sufficient iodine level in the population. Appropriate concentration of iodine in fortified salt needs to be decided according to local conditions. Special attention should be paid to the iodine level of pregnant women in Shanghai, and more education about iodine is necessary for the public health.
KeywordsSalt Iodine Shanghai Switzerland Children Pregnancy
We thank all the children and pregnant women who participated in this study, the healthcare professionals from the Centers for Disease Control and Prevention of the 17 districts in Shanghai.
Conceived and designed the experiments: Shoujun Liu, Xiaohui Su and Peng Liu; Performed the experiments: Shurong Zou, Jun Song and Zhengyuan Wang; Urine iodine and salt iodine test: Jun Song and Zhengyuan Wang; Analyzed the data: Zhengyuan Wang; Wrote the paper: Zhengyuan Wang and Shoujun Liu. All authors read and approved the final version of the manuscript.
The current study was supported by the National Nature Science Foundation of China (No. 81602851), Excellent Young Talents of Health System in Shanghai (No. 2017YQ043), the Fourth three year public health program (NO.GWIV-27.1), and Key Disciplines (No.15GWZK0801). None of the above funders played a role in the study design, data analysis or manuscript writing.
Compliance with Ethical Standards
The authors have no conflicts of interest relevant to this study.
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