According to a new study recently published in the online edition of the American Journal of Respiratory and Critical Care Medicine, the use of electronic cigarettes contributes to “the burden of chronic respiratory symptoms in youth.” However, after carefully examining the actual findings of this research, Dr. Michael Siegel, Professor in the Department of Community Health Sciences at Boston University School of Public Health, found the conclusions to be unfounded.
The study conducted by researchers at the University of Southern California involved a sample of 2,086 southern California 11th and 12th graders, interviewed in 2014, who were asked to report on bronchitis symptoms over a period of 12 months, via self-reported questionnaires. At baseline, the students were categorized according to their vaping habits: never users (had never used e-cigarettes), past users (used e-cigarettes but not in the past month), or current users (used e-cigarettes in the past month) of electronic cigarettes. Current users were further classified as infrequent users (had used e-cigarettes at least once in the past months) and frequent users (had used e-cigarettes at least twice in the last month).
In their analysis of the self-reported questionnaires examined the relationship between vaping and the presence of chronic bronchitis symptoms (chronic cough, phlegm or bronchitis) among youth. This relationship was then examined again after controlling for two variables: individual cigarette use and exposure to secondhand cigarette smoke in the home.
However on his website, Tobacco Analysis, Dr. Michael Siegel notes that the abstract of the study only features five conclusions:
1. There was a significant positive relationship between past e-cigarette use and bronchitis symptoms (not controlling for smoking or secondhand smoke exposure).
2. There was a significant positive relationship between current e-cigarette use and bronchitis symptoms (not controlling for smoking or secondhand smoke exposure).
3. The relationship between current e-cigarette use and bronchitis symptoms was significant for both infrequent and frequent users and was stronger for frequent users than infrequent users (not controlling for smoking or secondhand smoke exposure).
4. After controlling for smoking and secondhand smoke exposure or restricting the analysis to never smokers, there was still a significant positive relationship between past e-cigarette use and bronchitis symptoms.
5. After controlling for smoking and secondhand smoke exposure, there was no significant relationship between e-cigarette use (past or current) and asthma symptoms.
The abstract only mentions that “associations were attenuated by adjustment for lifetime number of cigarettes smoked and secondhand smoke exposure.” How convenient that they would neglect to share the results of their analysis after controlling for the two critical variables, right? They are however presented in the full study and Dr. Siegel was kind enough to share them on his blog:
1. After controlling for individual smoking and secondhand smoke exposure, there was no significant relationship between current e-cigarette use and bronchitis symptoms.
2. Among never smokers, there was no significant relationship between current e-cigarette use and bronchitis symptoms.
3. After controlling for individual smoking and secondhand smoke exposure, there was no significant relationship between either infrequent or frequent current e-cigarette use and bronchitis symptoms, and there was no significant trend.
The simple fact that they decided to focus solely on findings that create the appearance that there is a causal relationship between e-cigarette use and chronic bronchitis symptoms is proof of the deceptive nature of this study. And if that wasn’t enough, the press release issued by the American Thoracic Society (publisher of the American Journal of Respiratory and Critical Care Medicine) does the exact same thing – focus on the results prior to controlling for past cigarette smoking or exposure to second-hand smoke.
“The study found that when compared to those who never tried e-cigarettes, the risk of the respiratory symptoms was approximately 85 percent higher among past users, and double among current users,” the press release states. “These associations remained statistically significant for past users after being adjusted for smoking and secondhand tobacco smoke exposure and sociodemographic factors.”
However, Dr. Siegel emphasizes that “it is deceptive to state that the relationship between current e-cigarette use and bronchitis symptoms was “attenuated” after controlling for individual smoking and secondhand smoke exposure. Actually, the relationship was no longer statistically significant. In fact, in none of the many analyses conducted was there a significant relationship between current e-cigarette use and any adverse respiratory symptoms – bronchitic or asthmatic – after controlling for individual smoking and secondhand smoke exposure.”
The Boston University School of Public Health professor adds that without adjusting the findings for cigarette smoking and exposure to second-hand smoke, “one would actually expect to see an increase in respiratory symptoms in e-cigarette users (since we know e-cigarette use is highly correlated with smoking).” However, after taking into account the two very relevant variables, we are left with the conclusion that there was no association detected between e-cigarette use and chronic bronchitis or asthma symptoms.
So while we cannot say for certain that electronic cigarettes have no adverse effects on the human respiratory system, the fact remains that this particular study does not prove that there is any causal effect between vaping and chronic bronchitis symptoms in youth (not for lack of trying, though).
And Dr. Siegel isn’t the only reputed scientist with experience in electronic cigarette research to question the results of this controversial research. On his website, E-Cigarette Research, Dr. Konstantinos Farsalinos, a research fellow at the Onassis Cardiac Surgery Center in Athens, Greece, and a supporter of electronic cigarettes as a less dangerous alternative to tobacco smoking, also points out the flaws of the study.
Apart for the points made by Dr. Siegel, the Greek researcher also identified another major problem with this study. “When I first read the media stories I was puzzled because I thought chronic bronchitis is a rare condition at this young age,” Farsalinos writes. “So, I looked for the CDC data on the incidence of chronic obstructive lung disease (COPD = chronic bronchitis and emphysema). For the 3-year period of 2007-2009, the prevalence of COPD among US adults was 5.1%. Prevalence increased with age, with the highest observed in age groups 75-84 year. For age group 18-24 years, the prevalence was 2.5%. The study in South California found that the age group 16-18 years had an amazing 19.2% prevalence of “bronchitis”. This is an unbelievable number. So, is there an epidemic of COPD among South Californian adolescents? Should the local health authorities and the WHO be alerted? I don’t think so. In reality, the self-reported prevalence of symptoms has been just mispresented as lung disease, but its accuracy is close to zero.”
Dr. Michael Siegel and Dr. Konstantinos Farsalinos do a great job of telling the whole story behind this deceptive study, but unfortunately, their websites don’t have the reach of Big Media outlets, so the general public will be left with the flawed conclusion that e-cigarettes are linked to chronic bronchitis. Giants like the Mail Online or the New York Daily News have already published these purposely deceitful findings as legit scientific evidence, without so much as mentioning the points raised by Dr. Siegel and Dr. Farsalinos. Who knows how many e-cigarette users will give up vaping and return to smoking cigarettes, or how many smokers thinking about switching to e-cigs will give up on the idea because of this misinformation?