Competing interests: The BMJ has judged that there are no disqualifying financial ties to commercial companies. The author declares the following other interests: Within the past five years I have received grant funding from the US National Cancer Institute, National Institutes of Health, the California Tobacco-Related Disease Research Program (research funds derived from the state tax on cigarettes), and the California Tobacco Control Program. I own one share of stock in each of three tobacco companies, including PMI, for research and advocacy purposes. Since 1997, I have been a faculty employee of the University of California, San Francisco. I am semi-retired and receive a pension from the university. Further details of The BMJ policy on financial interests are here: https://www.bmj.com/sites/default/files/attachments/resources/2016/03/16-current-bmj-education-coi-form.pdf. Provenance and peer review: Commissioned; not externally peer reviewed.