Footnotes

• Contributors AS: design and writing. EKO: supervision. MTO: data curation. MYO: editing of 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.

• Patient consent for publication Parental/guardian consent obtained.

• Provenance and peer review Not commissioned; internally peer reviewed.