Footnotes

• Twitter @OlgaKoksh

• Contributors All authors substantially contributed to the conception of this work, drafting, proofreading and preparing this manuscript for the review. The data was collected and analysed by OK who also led the work on the 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 Not commissioned; externally peer reviewed.