Footnotes

• Contributors MA-B conceptualised and designed the study. MA-B contributed in the writing of the first draft of the manuscript, reviewed the revisions and approved the final manuscript as submitted.

• 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; internally peer reviewed.