May 30, 2018

Stanton A. Glantz, PhD

First evidence linking e-cigs to COPD in the population

The biological and clinical evidence that e-cigarettes are really bad for lungs has been rapidly piling up;  now the first evidence linking e-cigarette use with chronic obstructive pulmonary disease (COPD) has been presented.  At the American Thoracic Society meeting in May 2018, Mario Perez and colleagues presented an analysis of the NIDA/FDA PATH study and found a strong link between e-cigarette use and COPD.

They compared having been told they were diagnosed with COPD (including COPD, chronic bronchitis, or emphysema) among current (some day or every day) with people who did not use e-cigarettes.  They controlled for other tobacco product usage and secondhand smoke exposure using a technique called propensity score matching.  Accounting for matched propensities, there were 1321 e-cigarette users and 1321 nonusers. E-cigarette users were about twice as likely to have COPD (odds ratio, 1.86; 95% CI, 1.22-2.83).

Like our earlier paper that showed that daily e-cigarette users are about twice as likely to have had a heart attack, Perez and colleagues’ result is based on a cross-sectional analysis, a snapshot in time, that finds an association between e-cigarette use and COPD.  PATH is a longitudinal study, so, over time, it will become possible to test for a longitudinal association.  But that will likely take years for the necessary new cases to accumulate. 

The important thing to do is to interpret this cross-sectional COPD association in the context of all the biological and clinical evidence that would lead you to expect such a link.  Since we reviewed the evidence that e-cigarettes trigger inflammatory processes and depress immune function in lungs and are associated with kids having chronic bronchitis, the biological evidence has rapidly accumulated.  Two recent animal and human studies (Reinikovaite et al, and Garcia-Arcos et al) have shown that exposure to e-cigarettes produces COPD-like changes to the alveoli (air sacs).  You don’t have to be a molecular biologist to understand this damage.  Just look at the pictures in these papers.  There is also evidence of genetic changes in nonsmokers who never used an e-cigarette in one session that explain these effects (Staudt et al).  These genetic changes include suppression of the p53 tumor suppressor gene, that suggests that, despite delivering lower levels of carcinogens, e-cigarettes could be increasing the risk of lung cancer.

Viewed from this perspective, Perez’ epidemiological findings are exactly what one would expect based on the biology.

In addition, nicotine is directly implicated as causing some of these changes and directly damages lungs.  It is time for FDA and e-cigarette enthusiasts to stop ignoring the evidence that nicotine itself has adverse biological effects beyond its addictive properties. 

The more we learn about e-cigs the more dangerous they look.

Here is the full citation:  Perez MF, Atuegwu N, Mead E, Oncken C, Mortensen EM. E-cigarette use is associated with emphysema, chronic bronchitis and COPD. Presented at: American Thoracic Society 2018 International Conference; May 18-23, 2018; San Diego, CA. Poster 402.  The abstract is available here.

Comments

Comment: 

Was there an accounting for the fact that the vast majority of E-Cigarette users are or were combustible tobacco users, in some cases for decades?

Would we not need to study e-cigarette users who never used combustible tobacco product to rule out a tainted subject pool?

Comment: 

As noted in the blog post, the authors controlled for smoking and secondhand smoke exposure.   Our analysis of e-cigs and heart attacks (cited in the blog post) shows that the effects or e-cigs and conventional cigarettes are independent and compoud.

Comment: 

There is so much wrong with this study I’m not even going to bother dissecting it. Just the fact that most e-cigarette users were once long term smokers severely skews the results and more importantly no other study by credible researchers has shown that nicotine damages lung tissue. It’s easy to see what your agenda is and real researches will see this for exactly what it is.

Comment: 

The studies cited at the end of the blog post show direct effects of nicotine on lung tissues. All you need to do is look at the pictures to see the destruction of the air sacs.

Comment: 

Has this study been peer reviewed? And what were the controls used? Because this study appears to have several flaws

Comment: 

Abstracts presented at the American Thoracic Society meeting are peer reviewed.

Comment: 

Doesn't COPD have an extremely large latency period? How can this cross sectional survey even come close to showing causation? You can "control for smoking and second hand smoke exposure" all you want, but if the only examples are from people who were smokers you are a long way from showing vaping causes COPD.

Comment: 

The experimental studies cited in the blog post show that the adverse effects of e-cigarette use start to appear relatively quickly.  Cross-sectional studies show associations not causality, but the fact that the associations in the cross-sectional study are exactly what one would expect based on the biology increases confidence in the fact that they are finding something real.

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