Study on the Applicability of WHO Serum Iodine Standards for Normal Individuals in the Chinese Population—A Cross-sectional Study from Six Provinces in China - Mengxue Du; Yang Du; Yanhong He; Yun Chen; Fengfeng Zhang; Weidong Li; Ling Zhang; Zhihui Chen; Xiaofeng Wang; Liangjing Shi; Hongmei Shen; Lixiang Liu (Biological Trace Element Research, 2025)