Assessing the impact of drinking water iodine concentrations on the iodine intake of Chinese pregnant women living in areas with restricted iodized salt supply



The supply of non-iodized salt and the water improvement project have been conducted to reduce the iodine concentration in drinking water in areas with elevated water iodine. We aimed to assess the impact of water iodine concentration (WIC) on the iodine intake of pregnant women in areas with restricted iodized salt supply, and determine the cutoff values of WIC in areas with non-iodized salt supply.


Overall, 534 pregnant women who attended routine antenatal outpatient visits in Zibo Maternal and Child Health Hospital in Gaoqing County were recruited. The 24-h urine iodine excretion (UIE) in 534 samples and the iodine concentration in 534 drinking water samples were estimated. Urinary iodine excretion, daily iodine intake, and daily iodine intake from drinking water (WII) were calculated. The relationship between WIC and daily iodine take was analyzed.


The median WIC, spot urine iodine concentration (UIC), and 24-h UIE were 17 (6, 226) μg/L, 145 (88, 267) μg/L, and 190 (110, 390) μg/day, respectively. A significant positive correlation was found between WIC and UIE (R2 = 0.265, p < 0.001) and UIC (R2 = 0.261, p < 0.001). The contribution rate of WII to total iodine intake increased from 3.0% in the group with WIC of < 10 μg/L to 45.7% in the group with WIC of 50–99 μg/L.


The iodine content in drinking water is the major iodine source in pregnant women living in high-water iodine areas where iodized salt supply is restricted. The contribution rate of daily iodine intake from drinking water increases with the increase in water iodine concentration.

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We thank the Center for Disease Control and Prevention of Gaoqing County for their support and help in field investigations. We appreciate the co-cooperation and participations of teachers, nurses, and pregnant women.


This work was supported by the National Natural Science Foundation of China (NSFC Grant no. 81920108031, 81330064 and 71774115) and Science Foundation of Tianjin Medical University (no. 2017KJ235).

Author information




ZW, CW, and TL were responsible for the study design. GM performed the field investigation, the data analysis, and writing of the manuscript. CY took part in the  field investigation and the data analysis. LL, PZ, GS, and SJ performed the laboratory detection of iodine. ZQ, ZY, DS, WW, and WG took part in the field investigation and laboratory detection. All authors read and approved the final version of the manuscript.

Corresponding author

Correspondence to W. Zhang.

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All authors and companies or organizations do not have any conflicts of interests.

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This study was approved by the Ethics Committee of Tianjin Medical University. All procedures performed in the studies were in accordance with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. All participants provided an informed consent after receiving a full explanation of the purpose and procedure of the study.

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Gao, M., Chen, W., Dong, S. et al. Assessing the impact of drinking water iodine concentrations on the iodine intake of Chinese pregnant women living in areas with restricted iodized salt supply. Eur J Nutr (2020).

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  • Drinking water iodine concentration
  • Urine iodine excretion
  • Water improvement project
  • Total iodine intake