Footnotes

• Contributors JY and JK collected and analysed BAT’s marketing activities under the supervision of SL. JY prepared the first draft of the manuscript. JK and SL reviewed all of the drafts and helped to prepare the final 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.

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