More evidence that e-cigs inhibit quitting conventional cigs in the real world

Ling and Popova recently published "Alternative Tobacco Product Use and Smoking Cessation: A National Study" in American Journal of Public Health that , like earlier research, found  that an important reason that adults tried e-cigarettes (as well as smokeless products) was because they through they would help them quit smoking conventional cigarettes.

Ever use of e-cigarettes was not associated with being a successful quitter (OR 1.09; 95% CI 0.72-1.65) but was associated with being an unsuccessful quitter (OR=1.78, 95% CI 1.25-2.53) compared to people who had never tried to quit.

This evidence is from a cross-sectional study (i.e., a snapshot in time) rather than following the same people over time (a longitudinal study), so by itself does not allow making causal conclusions.  Taken with the two published longitudinal studies, one of which found that e-cig use had no effect on quitting and the other of which showed lower quit rates for e-cig users, it does add to the case that the loudly made claims that e-cigs help smokers quit are wrong.


Skewed Opinion?

Considering the first study quotes "


Awareness of ENDS is high, especially in
countries where they are legal (i.e., the U.S. and UK). Because trial
was associated with nondaily smoking and a desire to quit smoking, ENDS
may have the potential to serve as a cessation aid.


and the second study you cite says only 51% of the ecig users used them to actually quit tobacco then you are kind of skewing the results in your headline.

Yes some people dual use ecigs with tobacco, but is this hardly a revelation of any significance. The fact is if they use 'less' tobacco whilst using ecigs or not.

Now that would be a study with some credibility rather than trying to prove a point that has no relevance to "the real world"



Why real word population studies are better

Both studies measure the effects of e-cigs on quitting in the real world. 

There are two ways in which e-cigs could affect quitting:

    1.  The availability of e-cigarettes could increase or decrease quit attempts.
    2.  E-cigarettes could make an individual quit attempt  more or less likely to succeed.

Clinical trials of e-cigs on quitting success among people trying to quit only consider item 2, but both effects are important in the real world.  What the population-based studies show is that the net effect of the availability of e-cigarettes either has no nte effect on quitting or a negative effect on quitting.

Because these studies look at the overall behavior they do not provide any information on how they affect items 1 or 2 separately.

The "first study" (the ITC study) found that most adults using e-cigs were using them to try and quit smoking, which is what led them to the conclusion that they might work as a cessation aid.

If you carefully read the study carefully you will see that what the study found was that there was no significant difference in actual quitting (p=0.516).

Since the paper did not reprot the actual quit rates,  I wrote the authors and asked for what the magnitude of the effect of e-cig use was on quitting.  The odds of quitting conventional cigarettes among e-cigarette users was 0.811 (95% CI: 0.431-1.526) compared to people not using e-cigarettes.  While not anywhere near statistically significant (the fact that the confidence interval is wide and nearly centered on 1.0 shows this, which contains information equivalent to the p value), the point estimat is below 1.0.  The fact that the odds ratio is less than one shows that ecig users quit cigarettes less often than nonusers (although this difference is within sampling variability).


Toxic e cigarrettes

They need to make more studies for people like me with chronic bronchitis. My husband doesn't have any respirwtory problems so it doesnt affect him. My sons room is under mine so I even smell when he uses the marijuana in it. I smell the toxic burned oil.more like I taste it. It is affecting my bronchious really bed and I get headaches. The e cigarretes are horrible.