That hasn't been unequivocably established. For example, a 2016 review article "Cardiovascular Toxicity of Nicotine: Implications for Electronic Cigarette Use" published in Trends in Cardiovascular Medicine (http://sci-hub.cc/10.1016/j.tcm.2016.03.001) concluded:
> Studies of the pharmacology and toxicology of nicotine in animals and
some epidemiologic studies in people support the biological
plausibility that nicotine contributes to acute cardiovascular events
in smokers with underlying CVD, and exerts pharmacologic effects that
could contribute to accelerated atherogenesis. Short-term nicotine
use, such as nicotine medication to aid smoking cessation, appears to
pose little cardiovascular risk, even to patients with known
CVD. Longer term nicotine use, such as in ST users, appears not
accelerate atherogenesis, but may contribute to acute cardiovascular
events in the presence of CVD.
"may contribute to acute cardiovascular events in the presence of CVD" is a far cry from being the sole (or even principle) cause of smoking-related cardiovascular disease.
That's much higher than I'd assumed, and bad news for those who want to claim that e-cigarettes are essentially safe.
EDIT: DanBC points out below[1] that it's wrong to assume the cardiovascular disease is caused primarily by nicotine, which is how I came to think it was about 1/3. So I retract this interpretation, but leave it up for posterity :)
I couldn't find that evidence anywhere in your link. A report by Public Health England estimated e-cigarettes to be at least 95% less harmful than combustible tobacco.
The report you linked does not explain the 95% number, and following their citations bottomed out in articles that don't contain that number either. I'd need to spend more time looking through those before I'd feel comfortable saying that no existence for the 95% harm reduction claim can be found in the tree of citations spinning out from the PHE report, but please be aware that as of now you have not provided evidence for that claim. I'd be pleased if you would, since it would probably save me a lot of time later.
Thanks, this is more clear and straightforward about where they got that number, though the relevant citation ends up being the same as in the longer document.
The evidence cited in that summary is the study 'Estimating the Harms of Nicotine-Containing Products Using the MCDA Approach'[1]. If you read that paper, I guarantee you will find yourself much less confident in the 95% harm reduction claim. Briefly, here's the method they employed:
* Convene a panel of "international experts" in a two day workshop.
* Ask each participant to separately rate how harmful they believe each type of nicotine-containing product is, on a scale of 0 (no harm) - 100 (cigarettes).
* Weight/average the scores and publish the results
In case anyone is inclined to think that counts as "evidence", be aware that the authors of that study don't:
"A limitation of this study is the lack of hard evidence for the harms of most products on most of the criteria"
They fail to mention in particular the lack of long-term evidence for some of the products, which have not been available long enough to properly measure.
In any case, I am aware that vaping nicotine is much safer than combusting tobacco (though I think the latter is a lot yummier). However, I found this to be an interesting case study in how a report can pull out precise and scientific-looking numbers like 95% and trust that people for the most part will take that at face value without looking into the scientific validity of the claim.
Which part of your link, or the large surgeon general's report, say that "about 1/3 of smoking related deaths are due more to the nicotine than the smoke"?
Out of 480,317 deaths attributed to cigarette smoking, 160K were due to cardiovascular diseases and metabolic diseases. 160/480 = .3333
This calculation makes the charitable assumption that none of the deaths categorized as Cancer were due to the nicotine itself. The categories are Cancer, Cardiovascular Diseases and Metabolic Diseases, Respiratory Diseases, Perinatal Conditions, Residential Fires, Secondhand Smoke.
Why are you assuming all the cardiovascular disease was caused by nicotine? That doesn't seem to be what the full report is saying, although maybe I missed it.
Why are you assuming the nicotine is solely to blame, and not for example the carbon monoxide?
Page 419:
> The 2010 Surgeon General’s report reviewed in great detail the mechanisms by which cigarette smoking leads to CHD; Figure 8.3 provides an overview of the mechanisms considered (Benowitz 2003). In addition to supporting the findings of previous reports, the 2010 report concluded that smoking produces insulin resistance that, together with chronic inflammation, can accelerate the development of both macrovascular and microvascular complications, including nephropathy, and the use of nicotine replacement and medications to aid smoking cessation in smokers with CHD produces far less risk than continued smoking.
Page 420:
> Nicotine is a sympathomimetic agent that increases heart rate and cardiac contractility, transiently increasing blood pressure and constricting coronary arteries (see Chapter 5). Nicotine may also contribute to endothelial dysfunction, insulin resistance, and lipid abnormalities. However, international epidemiologic evidence, and data from clinical trials of nicotine patches, suggests that chemical components in smoke other than nicotine are more important in elevating the risk of death from MI and stroke
> Why are you assuming the nicotine is solely to blame, and not for example the carbon monoxide?
Good point, thanks.
I will relax my assumption to "some of the cardiovascular disease is caused by nicotine," and admit that I don't have enough information to know what percentage of smoking deaths are attributable to just the nicotine.
Do you happen to know if they've figured this out?
Nicotine is one of my favorite drugs, which is why I personally keep a safe distance from it. E-cigarettes may be worse for you than a glass of water, but I am pretty happy about all the lives they're saving as they replace regular cigarettes.
