My commentary on the conclusions and implications of the National Academy of Sciences report on electronic cigarettes was just accepted as an op-ed piece in U.S. News & World Report. I expect it to be published tomorrow. For this reason, I have had to take down the original commentary. However, below I have posted the parts of the original blog post that had to be cut from the op-ed because of length concerns. Also, I will post a link to the op-ed as soon as it appears.
The key findings of the report are:
1. "There is
substantial evidence that except for nicotine, under typical conditions
of use, exposure to potentially toxic substances from e-cigarettes is
significantly lower compared with combustible tobacco cigarettes."
"There is conclusive evidence that completely substituting e-cigarettes
for combustible tobacco cigarettes reduces users’ exposure to numerous
toxicants and carcinogens present in combustible tobacco cigarettes."
"There is moderate evidence that risk and severity of dependence are
lower for e-cigarettes than combustible tobacco cigarettes."
"There is moderate evidence that second-hand exposure to nicotine and
particulates is lower from e-cigarettes compared with combustible
5. "There is no available
evidence whether or not e-cigarette use is associated with clinical
cardiovascular outcomes (coronary heart disease, stroke, and peripheral
artery disease) and subclinical atherosclerosis (carotid intima
media-thickness and coronary artery calcification)."
"There is insufficient evidence that e-cigarette use is associated with
long-term changes in heart rate, blood pressure, and cardiac geometry
7. "There is no available evidence
whether or not e-cigarette use is associated with intermediate cancer
endpoints in humans. This holds true for comparisons of e-cigarette use
compared with combustible tobacco cigarettes and e-cigarette use
compared with no use of tobacco products."
8. "There is no available evidence whether or not e-cigarettes cause respiratory diseases in humans."
"There is limited evidence for improvement in lung function and
respiratory symptoms among adult smokers with asthma who switch to
e-cigarettes completely or in part (dual use)."
"There is limited evidence for reduction of chronic obstructive
pulmonary disease (COPD) exacerbations among adult smokers with COPD who
switch to e-cigarettes completely or in part (dual use)."
"While the overall evidence from observational trials is mixed, there
is moderate evidence from observational studies that more frequent use
of e-cigarettes is associated with increased likelihood of cessation."
"There is substantial evidence that e-cigarette use increases risk of
ever using combustible tobacco cigarettes among youth and young adults."
"There is conclusive evidence that, other than nicotine, the number,
quantity, and characteristics of potentially toxic substances emitted
from e-cigarettes is highly variable and depends on product
characteristics (including device and e-liquid characteristics) and how
the device is operated."
The Rest of the Story
I agree with all of the above conclusions, other than #12, which is not wrong on its face but needs careful interpretation.
Therefore, let me say a few
words about conclusion #12 above ("There is substantial evidence that
e-cigarette use increases risk of
ever using combustible tobacco cigarettes among youth and young
adults"). It is true that youth who experiment with e-cigarettes are
more likely to also experiment with tobacco cigarettes and therefore, to
become smokers. It would be shocking if this were not the case because
we know that youth who experiment with one risky behavior are more
likely to experiment with other risky behaviors. But this doesn't
necessarily mean that the experimentation with e-cigarettes is causing
the youth to start smoking.
For example, there probably
are not many kids who use heroin who have never taken a sip of alcohol.
If you did a study, you would find that alcohol use is associated with
later use of heroin. But this doesn't support the conclusion that
experimenting with alcohol causes kids to become heroin junkies. It
simply reflects the fact that kids who take huge health risks are more
likely to already have taken smaller health risks. A youth is not going
to decide to rebel one day by injecting a drug into their veins. The
rebellion process would likely start with a less hazardous behavior,
such as taking a toke on a cigarette and then for a very small number of
kids, they would end up progressing to hard drug use.
the important question is not whether youth who experiment with
e-cigarettes are more likely to end up smoking (of course they are!),
but instead, whether youth who experiment with e-cigarettes are more
likely to become addicted to vaping and then be led to smoking
addiction, such that without having become addicted to vaping, they
unlikely would have become smokers. So far, the evidence suggests that
this is not the case: very few youth have been identified who started as
nonsmokers, became regular vapers, and then progressed to smoking.