1 Population Health Sciences Institute, Newcastle University, Newcastle-upon-Tyne NE2 4AX, UK; Department of Otolaryngology-Head and Neck Surgery, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK. Electronic address: james.o'hara@newcastle.ac.uk.
2 Department of Otolaryngology-Head and Neck Surgery, Queen Elizabeth University Hospital, Glasgow, UK.
3 Department of Otolaryngology-Head and Neck Surgery, Newcastle-upon-Tyne Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK.
4 Population Health Sciences Institute, Newcastle University, Newcastle-upon-Tyne NE2 4AX, UK.