Analysis of the results of the surveillance on iodine nutrition among key population in vegetable-processing areas in Tongxiang, Zhejiang

ObjectiveTo evaluate the iodine nutrition status among key population from vegetable-processing areas in Tongxiang, Zhejiang, providing evidence for determination of the epidemic trends in regard of iodine deficiency. MethodsA total of 2,307 edible salt samples were measured for iodine contents using direct titration assay in accordance with the national surveillance program on iodine deficiency. Ammonium persulfate digestion was conducted to analyze 582 samples for urinary iodine among pregnant women, women at child-bearing age, 0 to 2-year-old infants and children at school age, respectively. Thyroid stimulating hormone (TSH) levels were measured in heel blood samples for 22 246 neonatal subjects using time resolution fluorescence immunization assay (TRFIA). ResultsThe minimal iodized salt coverage (89.24%) and qualified iodized salt usage (85.76%) were noticed in 2004. The median urinary iodine was 68.79 g/L in pregnant women and 94.02 g/L in 0 to 2-year-old infants, respectively. As a result, the urinary iodine level in major vegetable-processing areas was below national standard despite gradual increment, and 5.79% subjects (1290/22 246) demonstrated the TSH value greater than 5 mIU/L, with a year-by-year decline. ConclusionImportance shall be attached to the improvement in qualified iodized salt coverage and surveillance on iodine nutritional status among key population in vegetable-processing areas in the ensuing universal salt iodization (USI) and iodine supplement program.