Wednesday, November 04, 2015

New Population-Based Study Shows that Adult E-Cigarette Use Has an Overall Benefit for the Public's Health

A new study published in the journal Nicotine & Tobacco Research is the first population-based study to comprehensively examine the pattern of electronic cigarette use among U.S. adults and demonstrates that the use of these products is having a strong net benefit for the public's health.

(See: Delnevo CD, et al. Patterns of electronic cigarette use among adults in the United States. Nicotine & Tobacco Research, 2015, 1-5; doi: 10.1093/ntr/ntv237.)

The study reports data from the 2014 National Health Interview Survey (NHIS), a nationally representative survey of the non-institutionalized, civilian population. This was the first time that the NHIS inquired about electronic cigarette use. The paper reports the breakdown of adults in the population on the basis of smoking status (current smoker, former smoker, and never-smoker) and for each category, the percentage of persons who reported using e-cigarettes ever, some days, and every day.

The former smokers are further broken down into recent quitters (those who quit within the past year), former smokers who quit 2 to 3 years ago, and former smokers who quit 4 or more years ago.

Using these data, I was able to estimate the overall proportion of daily electronic cigarette users in each of the smoking status groups. The public health implications of electronic cigarette users in each of the groups is as follows:

Daily and some day smokers (current smokers): POSITIVE - The more smokers can switch to electronic cigarettes, the better. While some anti-tobacco advocates have claimed that e-cigarettes impede smoking cessation, the scientific evidence support the opposite conclusion. Moreover, smokers who use e-cigarettes are not likely to have quit in the absence of e-cigarettes.

Recent quitters (quit within past year): POSITIVE - These are most likely former smokers who were able to quit by using electronic cigarettes.

Former smokers, quit 2 to 3 years ago: NEUTRAL - It is not clear whether these represent smokers who quit because of e-cigarettes or former smokers who started vaping.

Former smokers, quit 4 or more years ago: NEGATIVE - These likely represent former smokers who started vaping. However, it should be noted that the public health implications of this group are not necessarily negative, as it is possible that in the absence of e-cigarettes, these former smokers would have relapsed to smoking.

Never-smokers: NEGATIVE - Obviously, it is not beneficial for never-smokers to initiate nicotine use.

The Rest of the Story

Based on the reported NHIS data, the proportion of electronic cigarette smokers in each of the smoking status categories is as follows:

Current smokers: 49.9% (POSITIVE)
Recent quitters: 32.4% (POSITIVE)
Former smokers, quit 2 to 3 years ago: 9.5% (NEUTRAL)
Former smokers, quit 4 or more years ago: 3.0% (NEGATIVE)
Never-smokers: 5.2% (NEGATIVE)

Based on this analysis, of all adults who are every day vapers, 82.3% are using these products with a health benefit, 8.2% are using them with a health risk, and for 9.5% we don't have enough information to determine whether they are benefiting or being harmed. It seems quite clear that overall, the use of electronic cigarettes among the adult population is having a strong net public health benefit. Moreover, the proportion of daily vapers who appear to be former smokers who quit by using e-cigarettes is substantial, representing nearly one-third of all daily vapers.

In future surveys, it would be helpful to add questions inquiring whether former smokers had quit using e-cigarettes or whether they had relapsed back to nicotine use.

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