Footnotes

• Contributors All authors took an active role in the manuscript. LRM, MLG and AL conceptualised and designed the study. LRM collected the data. LRM and AG analysed and interpreted the data. LRM drafted the initial manuscript. LRM, AG, SS, MLG, MKP and AL revised the manuscript for important intellectual content. SS, MLG and AL obtained funding for this study, and AL is responsible for the overall content. All authors approved the final manuscript submitted.

• Funding Research reported in this publication was supported by National Cancer Institute and FDA Center for Tobacco Products (CTP) Awards (NCI/FDA Grants #U54CA180905 and #U54CA228110).

• Disclaimer The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH or the Food and Drug Administration.

• Competing interests MLG received a research grant from Pfizer and served as a member of a scientific advisory board to Johnson & Johnson. All other authors have no competing interests to declare.

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

• Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.