[1] Harbin Med Univ, Natl Hlth Commiss Key Lab Etiol & Epidemiol, Chinese Ctr Dis Control & Prevent, Inst Endem Fluorosis Control,Ctr Endem Dis Control, Harbin 150081, Peoples R China
[2] Harbin Med Univ, Educ Bur Heilongjiang Prov, Heilongjiang Prov Key Lab Trace Elements & Human H, Harbin 150081, Peoples R China
[3] Harbin Med Univ, Educ Bur Heilongjiang Prov, Key Lab Etiol & Epidemiol, Harbin 150081, Peoples R China
[4] Harbin Med Univ, Chinese Ctr Dis Control & Prevent, Inst Kashin Beck Dis Control & Prevent, Harbin 150081, Peoples R China