1. Otorhinolaryngology Hospital, The First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan Road II, Guangzhou 510080, P.R. China
2. Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, P.R. China
3. Department of Medicine, The University of Hong Kong, Hong Kong, SAR, P.R. China