Covid 19: How harm reduction advocates and the tobacco industry capitalised on the pandemic to promote nicotine

Dear Editor

In their recent article in the BMJ “Covid 19: How harm reduction advocates and the tobacco industry capitalised on the pandemic to promote nicotine[1] Horel and Keyzer totally confuse the issue regarding smoking and COVID-19 by failing to distinguish two separate main questions. “Does smoking affect the probability of being infected?” and “Among those who get infected does smoking affect the probability of death?” Thus they present evidence from the Open Safely dataset and other studies on increased mortality in smokers as an attempt to “roundly disprove” a hypothesis “that smoking protects against COVID-19”, when that evidence does not actually address that hypothesis.

As regards the first question, Farsalinos, as pointed out in the article, observed that the prevalence of smoking among patients hospitalized with COVID-19 was substantially lower than that expected from national statistics. While this could well be due partly to the incompleteness of smoking data in hospital records in a number of the studies, better and quite clear evidence supporting a reduced risk of COVID-19 positivity in current smokers comes from studies of those tested for COVID-19 (e.g. [2-6]). Although the overall evidence relating to positivity is perhaps less clear from studies of other populations or using other designs, there is little or no suggestion in the epidemiological evidence that I have studied that smokers are more likely to get the virus.

In relation to the second question, the evidence on mortality among patients with COVID-19 does indeed suggest that smoking is associated with a clearly increased risk of death in unadjusted analyses. However, this increase seems to disappear when adjustment is made for comorbidities (e.g. [4-7]). In other words a smoker and a non-smoker with equivalent medical history pre-pandemic seem to have a very similar risk of mortality if they get COVID-19.

Horel and Keyzer also strongly imply that tobacco industry consultants only work so as to promote a view of the evidence that is favourable to the industry. As a consultant to the tobacco industry for over 30 years that is not at all my experience. When I started work as a consultant to one of the major tobacco companies I was told that they wanted my unbiased assessment of what the evidence showed. As a past national champion at both chess and bridge whose main interest in life is in accurate problem solving, I have always attempted to give the true picture and have published widely in the literature, including major reviews underlining the extremely strong relationship between smoking and major diseases (e.g. [8 9]).

Horel and Keyzer seem far too concerned with undisclosed financial links to the industry, and in implying that any results emanating from the industry are not to be trusted. They should spend more time actually looking at the evidence on smoking and COVID-19, which they misleadingly present.

Please note that this response was not financially supported by the tobacco industry.

Peter N. Lee
P.N. Lee Statistics and Computing Ltd.
17 Cedar Road
Sutton, Surrey, SM2 5DA
United Kingdom

References

1. Horel S, Keyzer T. Covid 19: How harm reduction advocates and the tobacco industry capitalised on the pandemic to promote nicotine. BMJ 2021;373:n1303.
2. Adorni F, Prinelli F, Bianchi F, Giacomelli A, Pagani G, Bernacchia D, et al. Self-reported symptoms of SARS-CoV-2 infection in a nonhospitalized population in Italy: Cross-sectional study of the EPICOVID19 web-based survey. JMIR Public Health Surveill 2020;6(3):e21866.
3. Chadeau-Hyam M, Bodinier B, Elliott J, Whitaker MD, Tzoulaki I, Vermeulen R, et al. Risk factors for positive and negative COVID-19 tests: a cautious and in-depth analysis of UK Biobank data. Int J Epidemiol 2020;49(5):1454-67.
4. Ioannou GN, Locke E, Green P, Berry K, O'Hare AM, Shah JA, et al. Risk factors for hospitalization, mechanical ventilation, or death among 10 131 US veterans with SARS-CoV-2 infection. JAMA Netw Open 2020;3(9):e2022310.
5. Israelsen SB, Kristiansen KT, Hindsberger B, Ulrik CS, Andersen O, Jensen M, et al. Characteristics of patients with COVID-19 pneumonia at Hvidovre Hospital, March-April 2020. Dan Med J 2020;67(6).
6. Petrilli CM, Jones SA, Yang J, Rajagopalan H, O'Donnell L, Chernyak Y, et al. Factors associated with hospital admission and critical illness among 5279 people with coronavirus disease 2019 in New York City: prospective cohort study. BMJ 2020;369:m1966.
7. Jackson BR, Gold JAW, Natarajan P, Rossow J, Neblett Fanfair R, da Silva J, et al. Predictors at admission of mechanical ventilation and death in an observational cohort of adults hospitalized with COVID-19. Clin Infect Dis 2020;Published online ahead of print Sep 24, 2020 (doi: 10.1093/cid/ciaa1459).
8. Lee PN, Forey BA, Coombs KJ. Systematic review with meta-analysis of the epidemiological evidence in the 1900s relating smoking to lung cancer. BMC Cancer 2012;12:385.
9. Forey BA, Thornton AJ, Lee PN. Systematic review with meta-analysis of the epidemiological evidence relating smoking to COPD, chronic bronchitis and emphysema. BMC Pulm Med 2011;11:36.