Abstract: Received: 14 April 2022 | Accepted: 7 June 2022 DOI: 10.1002/cdt3.38 BRIEF REPORT Association of cannabis with chronic obstructive pulmonary disease and COVID‐19 infection Steven Lehrer1 | Peter H. Rheinstein2 1 Department of Radiation Oncology, Icahn School of Medicine at Mount Sinai, New York, New York, USA 2 Severn Health Solutions, Severna Park, Maryland, USA Correspondence: Steven Lehrer, Mt Sinai Medical Center, Box 1236 Radiation Oncology, 1 Gustave L. Levy Pl, New York, NY 10029, USA. Email: stevenlehrer@hotmail.com Edited by: Yi Cui Funding information Office of Research Infrastructure of the National Institutes of Health, Grant/Award Number: S10OD018522, S10OD026880 K E Y W O R DS cannabis, COPD, COVID‐19, lungs, tobacco In a 2012 study, occasional and low cumulative cannabis use was not associated with adverse effects on pulmonary function.1 With tobacco, the more used, the more loss of air flow rate and lung volume. The same was not true with cannabis use. Air flow rate increased rather than decreased with increased exposure to cannabis up to a certain level. An important factor that helped explain the difference in effects from tobacco and cannabis was the amount of each that was smoked. Tobacco users typically smoked 10–20 cigarettes daily, some even more. Cannabis smokers, on average, smoked only two to three times a month, so the average exposure to cannabis was much lower than for tobacco. People experiment with cannabis in their late teens and 20s, and some consume relatively low levels for years. Although heavy exposure to cannabis might damage the lungs, reliable estimates of the effects of heavy use were not available in the 2012 study, as heavy users were relatively rare in the study population. In the current analysis, we used data from UK Biobank (UKB) to assess the effect of cannabis on coronavirus disease (COVID‐19) infection and to determine whether cannabis lung damage might facilitate COVID‐19 infection in formerly heavy users. The UKB is a large prospective observational study comprising about 500,000 men and women (N = 229,134 men, N = 273,402 women), more than 90% White, aged 40–69 years at enrollment. Participants were recruited from across 22 centers located throughout England, Wales, and Scotland, between 2006 and 2010, and continue to be longitudinally followed for capture of subsequent health events.2 This methodology is like that of the Framingham Heart Study,3 with the exception that the UKB program collects postmortem samples, which Framingham did not. Our UKB application was approved as UKB project 57,245 (S.L. and P.H.R.). Doctor‐diagnosed chronic obstructive pulmonary disease (COPD) is from UKB data field 22,130. At enrollment, the subject was asked on a touchscreen, “Has a doctor ever told you that you have had any of the conditions below?” COPD (Chronic Obstructive Pulmonary Disease) was one of the options listed. The subject was asked, “Have you taken cannabis (marijuana, grass, hash, ganja, blow, draw, skunk, weed, spliff, dope), even if it was a long time ago?” If the answer was “yes,” cannabis use was recorded in the UKB data field 20,454, maximum frequency of taking cannabis, question asked: “Considering when you were taking cannabis most regularly, how often did you take it?” Answers were 1 = Less than once a month, 2 = Once a month or more, but not every week, 3 = Once a week or more, but not every day, and 4 = Every day. Subject was then asked (UKB data field 20455) “About how old..