Received: 17 July 2020
Accepted: 4 January 2021
First Online: 11 February 2021
Ethics approval and consent to participate
: This study is conducted under the project approved in the UK Data Service (Project id: 180005) and all data were anonymised. HES were annually reviewed and approved by NHS Multi-Centre Research Ethics Committee and SHeS by Research Committee for Wales. Written informed consent have been collected from all participants in the relevant health surveys.
: Not Applicable.
: All authors have completed the ICMJE uniform disclosure form at ExternalRef removed and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.