Beijing Municipal Health Bureau;
Beijing;
100053;
China;
Beijing Municipal Centers for Disease Control and Prevention;
Beijing 100013;
China;
School of Public Health;
Peking University Health Science Center;
Beijing 100083;
China;
School of Public Health;
Capital University of Medical Sciences;
Beijing 100069;
China;
Department of Epidemiology;
Chinese Academy of Medical Sciences & Peking Union Medical College;
Beijing 100005;
China;