Institute of Iodine Deficiency Disorders;
Center for Endemic Disease Control;
Chinese Center for Disease Control and Prevention;
Harbin Medical University;
Harbin 150081;
Heilongiiang;
China;
Jiangsu Center for Disease Control and Prevention;
Nanjing 210009;
Jiangsu;
China;
Qiqihar Medical University;
Qiqihar 161000;
Heilongjiang;
China;