Iodine nutritional status of 8-10 year-old school-age children after the implementation of new salt iodine standard in Suzhou / 公共卫生与预防医学

ABSTRACT

Objective To explore the iodine nutritional status among school-age children within 5 years of implementation of the new salt iodine standard in Suzhou, and to provide a basis for dynamically adjusting the salt iodization strategy. Methods The observation period (2012-2019) was divided into two sub-periods the adjustment transition period (2012-2014) and the adjustment completion period (2015-2019). According to the “Jiangsu Iodine Deficiency Disease Surveillance Program”, household salt samples and urine samples of school-age children aged 8 to 10 years were collected to detect the content of salt iodine and urine iodine. The coverage rate of iodized salt, qualified iodized salt consumption rate, and the median urinary iodine were determined. Results Totally 2 893 and 9 132 salt samples were collected in the adjustment transition and adjustment completion periods, with the median salt iodine content being 26.50 and 23.20 mg/kg, respectively. The iodized salt coverage rates were 97.03% (2 807/2 893) and 91.01% (2 633/2 893), and the consumption rates of qualified iodized salt were 97.25% (8 881/9 132) and 93.93% (8 578/9 132), respectively, in the two periods. The differences between the coverage rate of iodized salt and the consumption rate of qualified iodized salt between the two periods were statistically significant (χ2=38.465, P2 trend= 17.528, P<0.01). During the adjustment transition period, the median urinary iodine content of school-age children in Suzhou was 215.61 μg/L , and the proportion of urine iodine value <50 μg/L was 1.5%, while during the adjustment completion period the median urinary iodine and proportion of urine iodine value <50 μg/L were 192.60 μg/L and 2.40%, respectively. The difference in urine iodine between the two periods was statistically significant (Z=-9.918, P<0.01); Conclusions Five years after the implementation of the new salt iodization standard, the iodine nutritional level of school-age children in Suzhou was generally at an appropriate level. However, there was no significant changes in iodine nutritional levels in some areas after the adjustment of the new standard, suggesting that surveillance on iodine nutrition should be continuously consolidated in the future.