[1] Kunming Med Univ, Sch Publ Hlth, Dept Epidemiol, Kunming 650500, Yunnan, Peoples R China
[2] Ningbo Univ, Sch Med, Dept Epidemiol, Zhejiang Prov Key Lab Pathophysiol, Ningbo 315200, Zhejiang, Peoples R China
[3] Indiana Univ, Sch Med, Dept Pediat, 410 W,10th St,HS 1001, Indianapolis, IN 46202 USA
[4] Univ Malaya, Fac Med, Ctr Epidemiol & Evidence Based Practice, Dept Social & Prevent Med, Kuala Lumpur 50603, Malaysia
[5] Jinan Univ, Sch Med, Dept Epidemiol, Guangzhou 510632, Peoples R China