It's complicated.
The first thing Dr Farsalinos will tell you (he's a cardiac specialist who has a lot of experience with
ecig research) is that one clinical trial doesn't really provide any evidence, it's something others must try to replicate.
The next thing is that studies can sometimes be susceptible to funder bias or other forms of biasing. Then it must be compared to other studies on the same issue (for example if 6 say yes and 6 say no, there is no agreement on the basic hypothesis). All the evidence for the proposed effect must be compared at the same time - one study by itself usually has no real value (unless you are talking about a milestone such as Doll, Peto etc.).
Finally, there is a data mountain from Swedish Snus consumption that can only be referred to as gigantic - plus their national health statistics. We are talking here about tens of thousands of people who consumed nicotine without smoke for multiple decades. The NRT data resource is minuscule by comparison - in fact, pharma companies use the Swedish data for their NRT licensing applications because it is so large, over so many decades, that the results are conclusive. The NRT data is so small in comparison that it is regarded as exploratory. Little greater than the ecig data resource in some ways.
Does the Swedish data repeat the conclusion/s reached by this study/studies? I don't think so - Snus consumption has no clinical significance, the health effects are so small. But to be certain you would need to ask Dr Farsalinos, since being a cardiac specialist this is his field; or Prof Rodu, an expert on the pathology of
tobacco consumption, who would know how to place this study.
At this time all I can tell you is that many studies have shown that nicotine is the very devil - but they are all - and that's all - proven baseless, eventually. Sweden has unique national health stats and >20% of the population use Snus (some for decades), which often delivers more nicotine than cigarettes. These issues are not evident in Sweden and that means each of these (all are on different topics so it's hard to be specific) could be just another nicotine study that will be shown to be flawed or not applicable to humans in the real world (like many/most of the animal studies of nicotine, and the in vitro studies of nicotine, for example).
If you find a problem in Sweden then it's worth worrying about. There aren't any.
There is always something new to be discovered, but when it comes to nicotine you have to ask, "If I could find an isolated population where tens of thousands of people have consumed large quantities of
tobacco/nicotine without smoke for decades, and been intensively studied, with hundreds of clinical studies, using very large cohorts (however measured), and the national health statistics are unique as a result, and we had all the data we could possibly need - would it help me answer this question?"
We do - it's Swedish men - and multi-decade
ad lib consumption of nicotine has no clinical significance. In fact it's so hard to reliably identify any effect that professors of public health are happy to state the following:
"The difference in health outcomes between smokers who quit totally and smokers who switch to Snus is close to invisible. A Snus consumer is a non-smoker in health terms." - Rodu, Phillips (paraphrased).
I don't think they would be saying that if nicotine had any significant issues (outside of abuse).
However if you want to specifically examine the long-term effects of nicotine gum, and you find a clinically-significant effect: then you know it is specific to nicotine gum and little or nothing else. The Swedish data tells us that long-term consumption of oral nicotine without gum has no clinically significant effect, and this has been measured with data from tens of thousands over decades.
-------------
It's not really anything to do with this - but the Swedish data resource is so vast that we now know the principle factors for mouth cancer (oropharyngeal cancers, technically) are:
1. Smoking (by far the greatest risk)
2. Drinking (a significant risk)
3. HPV (human papilloma virus) - a type of cancer/wart transferred during oral sex
Swedish Snus is not even measurable on this scale (if the scale is 1 to 100, and smoking is at 100, then Snus is below 1).
Be clear: we are talking about the Swedish product, produced in Sweden, consumed there by Swedes - not any other product as we don't have the data.
-------------
