Received: 16 July 2018
Accepted: 25 February 2019
First Online: 15 May 2019
Ethics approval and consent to participate
: The data used in this study was obtained from a cross-sectional nationwide survey and data were anonymised. Ethical approval was included in Welsh Health Survey, and a local ethics committee ruled that participants were not required to be additionally consented for this study.
: Not applicable.
: The authors declare that they have no competing interests.
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