Footnotes

• Twitter @cfcamm, @dr_chrisallen

• CFC and ZR contributed equally.

• Contributors FC and CA were involved in the development of the survey and acquisition of survey data. FC, ZR and CA developed the analysis plan. All authors were involved in the interpretation of data and results. All authors contributed to the preparation and critical review, and approved the final manuscript.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Provenance and peer review Commissioned; internally peer reviewed.