Iodine excess or not: analysis on the necessity of reducing the iodine content in edible salt based on the national monitoring results.

Using national monitoring data collected between 1995 and 2009, this paper describes the change in trend with regard to the coverage of qualified iodized household salt and iodine status of the population in China since the implementation of universal salt iodization. The review indicates that the iodine content in edible salt increased from 16.2 mg/kg in 1995 to 42.3 mg/kg in 1999, then declined to 30.8 mg/kg in 2005 and has retained this level through the most recent data collection cycle, which is considered sufficient to achieve optimal iodine status. However, the median urinary iodine excretion level for children aged 8-10 at the national level has been consistently classified as "excessive iodine intake" since 1997, suggesting that although three adjustments on the standard of iodine content in edible salt have been made, the current content of salt iodization is still on the high side. The iodine content in edible salt could be lowered, and possibly adapted to local specific conditions such as water iodine content and the average daily intake of salt among the population in order to achieve a balance between preventing deficiency and reducing the risk of excessive intake.