[1] Peking Univ, Hlth Sci Ctr, Beijing, Peoples R China
[2] Harbin Med Univ, Harbin, Peoples R China
[3] Natl Hlth Commiss Peoples Republ China, Natl Inst Nutr, Chinese Ctr Dis Control & Prevent, Beijing, Peoples R China
[4] Natl Hlth Commiss Peoples Republ China, Hlth Key Lab Trace Element Nutr, Beijing, Peoples R China