[1] Tufts Univ, Eliot Pearson Dept Child & Human Dev, Medford, MA 02155 USA
[2] Wayne State Univ, Sch Med, Carman & Ann Adams Dept Pediat Prevent Res Ctr, Detroit, MI 48201 USA
[3] Beijing Normal Univ, Inst Dev Psychol, Beijing 100875, Peoples R China
[4] Vanderbilt Inst Global Hlth, Div Epidemiol, Nashville, TN USA
[5] Ctr Dis Control & Prevent, Guangxi, Peoples R China