New UCSF Smoking Cessation and Vaping Study
Statistics on smoking cessation coming out of UCSF and the Glantz blog have consistently foundered over the definition of "quitting", the value of "dual use", and the question of what level of efficacy "counts". Glantz has insisted that anything less than total cessation is not neutral but a block to cessation, and that there is no health benefit to smoking 4 cigarettes a day as opposed to 20. The new UCSF review of scientific literature in the AHA journal, to which Glantz has put his name along with Neal Benowitz and Rachel Grana, seems to soften that hard line.
Commenting on a study by Adkison, the UCSF literature review notes that reduction in smoking behavior was significant among vapers, but total cessation was not. The analysis of a study a small contingent of quitline callers by Vickerman reports that the rate of total cessation was lower among e-cig users than among those who used all other methods combined ("non [e-cig] users"), and this is interpreted to mean that e-cig use has no efficacy, rather than some efficacy. It would seem that vaping has to outperform everything else taken together in order to be seen as having any value.
Grana's own study found e-cig use to be "nonsignificant" as a predictor of quitting success, which does not mean that vaping did not help some smokers quit, but merely that it does not assure success.
A study by Choi and Forster found that 11% of participants who vaped turned out to be successful quitters, while 17% of non-vapers (i.e., smokers who used any other method, including cold turkey) managed to quit successfully. This is interpreted to mean that vaping is "not a significant predictor of having quit at follow up." Of course it could with equal justification be interpreted as an 11% success rate. The analysis of a study by Popova and Ling concludes that "adult smokers who ever used e-cigarettes were significantly less likely to be former smokers compared to those who never used e-cigarettes," which basically means that more former smokers have not vaped than have. It has nothing to do with the question of whether vaping can help some people quit. Essentially the claim is that vaping must outperform all other smoking cessation methods put together or it may not be considered at all helpful. No existing quit method could pass this test.
The Polosa smoking cessation study is discussed, although the numbers were small: of 23 vapers who smoked at baseline, 5 quit, and of the 18 who continued to smoke, 11 cut down to 4 smokes a day. It is hard to imagine that this could be considered anything but a better than 20% success rate. The second Caponnetto study found a 26% success rate (4%, 9%, and 13% for users of placebo e-cigs, low-nicotine, and high-nicotine respectively), but the control was seen as inadequate.
The well-publicized New Zealand study conducted by Bullen and colleagues, comparing vaping to the nicotine patch, found no significant difference between the two, although there was a consistent marginal superiority of e-cigs, which goes unmentioned here. Also, it is not explained why performance "only as good as the patch" is seen as a failure. Is the patch a failure because it is "only [almost] as good as an e-cig"?
The authors state that vaping products were not found to have efficacy "beyond what is seen in unassisted or low-assistance studies of smokers using NRT to quit." In other words, they are not proven better (or worse) than existing, approved therapies. It is not made clear why this is interpreted to mean that they have no value as a quit method, while the other methods with the same success rates are not thereby impugned. "In determining the effectiveness of smoking cessation therapy, active drug is considered efficacious when it outperforms placebo; therefore, the evidence to date from clinical trials does not demonstrate that e-cigarettes are efficacious for cessation." It would seem that the placebo value is all other methods put together, an unrealistically high bar.
But by far the most startling passage in this article is the following, under the heading "What to tell patients about e-cigarettes". "If a patient has failed initial treatment, has been intolerant of or refuses to use conventional smoking cessation medication, and wishes to use e-cigarettes to aid quitting, it is reasonable to support the attempt." This amounts to a stunning reversal of the stance associated with Professor Glantz, and the fact that he was willing to put his name on this text (as third author) could be seen as earth-shaking news.
The paragraph continues with instructions to warn the patient about the lack of regulation, the presence of some levels of toxicity, the lack of proof of efficacy as a cessation method, to counsel them not to vape indoors or around children, to phase out cigarettes entirely as soon as possible, and to set a quit date for e-cig use as well.
Nonetheless, this position by a scientist who has been a staunch, rigid, and absolute opponent is nothing short of amazing.