Footnotes

• Contributors We, the authors, declare hereby that all of us have substantially contributed to the conception and design, drafting this original article and reviewing it critically for important intellectual content. All the authors have also gone through the final version to be 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.

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