Footnotes

• Twitter @selmavalente

• Contributors All authors contributed to the conception, acquisition and/or interpretation of data, drafting the work or revising it critically for important intellectual content, and approval of the version published.

• 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.