Monday, October 20, 2014

New Cohort Survey Study Shows that Intensive E-Cigarette Use Greatly Increases Chances of Quitting Smoking; Also Shows Need for a Clinical Study

A new study, just published online ahead of print in the journal Nicotine & Tobacco Research, reports the results of a population-based survey of smokers followed up after two years to determine whether e-cigarette use was associated with higher or lower rates of smoking cessation.

(See: Biener L, Hargraves JL. A longitudinal study of electronic cigarette use in a population-based sample of adult smokers: association with smoking cessation and motivation to quit. Nicotine & Tobacco Research, 2014; doi:10.1093/ntr/ntru200.)

A baseline survey conducted in the Dallas and Indianapolis metropolitan areas in 2011/2012 identified 1,374 smokers who agreed to be re-contacted. Of these, 695 were successfully re-contacted in 2014. At the baseline interview, all respondents were current smokers and their use of electronic cigarettes was assessed. At the follow-up interview, smoking cessation was defined as abstinence from cigarettes for at least one month.

Smoking cessation rates were compared between intensive e-cigarettes users at baseline (daily use for at least one month), intermittent users (use more than once or twice but not daily for a month or more); and non-users (use no more than once or twice).

The chief finding was as follows: "Logistic regression controlling for demographics and tobacco dependence indicated that intensive users of e-cigarettes were 6 times as likely as non-users/triers to report that they quit smoking (O.R. 6.07, 95% C.I. 1.11, 33.2). No such relationship was seen for intermittent users."

The Rest of the Story

This is very important research, because it demonstrates that the intensive use of electronic cigarettes is associated with greatly increased rates of smoking cessation, even among a sample of dual users (i.e., all users were smokers at baseline).

However, the study also shows that for a number of reasons, many smokers do not become intensive e-cigarette users, and these individuals do not appear to gain any benefit from e-cigarettes in terms of smoking cessation. Trying to identify the factors that impede progression to more intensive electronic cigarette use could help to discover ways to make e-cigarettes more appealing and more likely to lead to more regular and sustained use. This would in turn increase the value of these products for smoking cessation.

One difficulty in interpreting the results of the study is that different levels of use may correspond with different levels of motivation to quit. For example, it may be that intensive users are more likely to be using e-cigarettes as part of an explicit quit attempt, while intermittent users are more or less experimenting with the products or using them for some other reason. This means that the results of any survey study must be interpreted strictly with respect to the nature of the use of the product in that specific sample.

This problem explains why two previous survey studies have found that e-cigarette users had lower chances of quitting. In those studies, many of the users were likely those who were not highly motivated to quit and who were not even making a quit attempt.

This is one major reason why a clinical study of the effects of e-cigarettes on smoking behavior is so critical. There is simply no other way to equalize the levels of motivation to quit and reasons for wanting to use an alternative product.

Interestingly, this study did not find a consistent relationship between electronic cigarette use and motivation to quit. Thus, even when one measures motivation to quit explicitly, it is not clear that controlling for this variable is adequate to account for differences between groups.

What does this all mean? It means that while survey research continues to be valuable, especially when it carefully defines and compares different subsets of e-cigarette users and attempts to focus on users who are explicitly making quit attempts, there are still major limitations with this methodology that cannot be overcome. We no doubt need many more survey studies to help elucidate the complex behavioral effects of  electronic cigarettes on smoking behavior. However, we also need a clinical study in which smokers at exactly the same level of motivation to quit are compared - that is, we need a randomized study in which the behavioral effects on smoking with e-cigarettes are identified and compared with another product such as NRT.

Disclosure: I have not received any funding or compensation from the tobacco, electronic cigarette, or pharmaceutical industries. However, I am seeking funding from several electronic cigarette companies to conduct a behavioral study on the effects of electronic cigarettes on smoking behavior.

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