1. Department of Otolaryngology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
2. Department of Otolaryngology, Shunyi Women and Children’s Hospital of Beijing Children’s Hospital, Beijing, China
3. Department of Otolaryngology, Cangzhou Central Hospital, Cangzhou, China
4. Department of Otolaryngology, Aviation General Hospital, Beijing, China
5. Heidelberg Institute of Global Health (HIGH), Heidelberg University, Heidelberg, Germany