Bad studies on e-cigarettes abound. Whether they are the result of questionable methodology or sometimes the result of genuine dishonesty on the part of the authors, major media outlets often use them to alert the public. One such study was published recently in the scientific journal Journal of Nuclear Medicine. The goal was to quantify a molecule (nitric oxide synthase) in order to “characterize oxidative stress and inflammation in the lungs of 15 participants”.
To do this, three groups were formed. The first had five members who had never smoked or e-cigarettes, the second had five smokers, and the last had five e-cigarette users.
In their findings, the authors said they found “preliminary evidence” that e-cigarette users “had more severe lung inflammation than smokers and controls. ”
Small sample size and ignoring smoking history
The results of the study reached Riccardo Polosa, a professor of medicine at the University of Catania and author of numerous studies on e-cigarettes.
After reading the complete analysis conducted by Wetherill et al, he sent a letter to the editor of the scientific journal that published the study. In his paper, he pointed out some inconsistencies and problems with the above study.
First, he warned that if more markers were found in the lungs of e-cigarette users than in the lungs of smokers, the study did not find any differences between the lungs of smokers and those of the participant group. The researchers noted, “The lack of differences between smokers and controls is not consistent, considering that smoking causes inflammatory responses and oxidative stress (……) .” This issue invalidates the interpretation of the study’s findings.
The size of the sample of participants used is also questioned. With only five participants in the three groups, “the likelihood of a chance finding is very high.”
In addition, the smoking history of the e-cigarette users was not indicated. In other words, the lung damage in this group of e-cigarette users could have been caused by potential past smokers. Since it is not possible to distinguish between damage caused by e-cigarettes and smoking in this case, the results of the study cannot be considered either.
As a reminder, Riccardo Polosa conducted a study in 20172 that examined the effects of e-cigarettes on the lungs of participants who had never smoked or had never smoked e-cigarettes in the past. After three and a half years of follow-up, he concluded that “there was no decrease in spirometry, no respiratory symptoms, no change in lung inflammatory markers in exhaled air, and no signs of lung injury.” Early.”
Riccardo Polosa is a member of the Center of Excellence for Accelerated Harm Reduction (CoEHAR), an organization funded in part by the Tobacco Free World Foundation, a division of tobacco company Philip Morris International.
1 Wetherill RR, Doot RK, Young AJ, Lee H, Schubert EK, Wiers CE, Leone FT, Mach RH, Kranzler HR, Dubroff JG. Molecular imaging of lung inflammation in e-cigarette and combustible cigarette users: a pilot study. Journal of Nuclear Medicine. 2023 May;64(5):797-802. doi: 10.2967/jnumed.122.264529. epub 2023 Jan 19. PMID: 36657981; PMCID: PMC10152129.
2 Ricardo Polosa, Fabio Sibella, Pasquale Carpenetto, Marilena Maria, Umberto Prospelini, Cristina Russo, Donald Tashkin. Health effects of e-cigarettes: a 3.5-year prospective study of daily users who have never smoked. Scientific Reports| 7:13825 | DOI: 10.1038/s41598-017-14043-2.