Footnotes

• Contributors IS developed the idea, analysed the data and led the writing of the manuscript. AP helped write programming code and edited the manuscript. RJS helped write programming code, supervised the analyses and edited the manuscript. All authors contributed to the design, analysis and writing 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 IS is the consulting medical director for Cirque du Soleil but was not paid for the work related to this manuscript.

• Patient consent Not required.

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

• Data sharing statement We will make summary data available but do not have the authority to release raw data because it is owned by a private company, and it might allow someone to identify individual participants.