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Absence of at least one appropriate control

Posted by pearsek on 09 Feb 2015 at 20:57 GMT

While this study makes for interesting reading and provides valuable information, I find myself very disappointed to see that it has not used the most basic of 'e-liquid' available.

While I do understand that there are many forms of ecigarette in respect of the hardware available for vaping, and an even greater number of eliquid concentrations, there is a fundamental and flavourless liquid at the base of most of them that provides the one single definitive solution through which an experiment can provide results regarding e-cigarettes generally. That liquid consists of propylene glycol and/or vegetable glycerine, water, and medicinal grade nicotine.

Surely results regarding levels of free radicals might (or might not) be significantly different according to the chemical constitution of the flavourings added to this fundamental eliquid solution, and as such the results demonstrated in this paper would exist on a far more solid grounding had this been taken into account? Surely it is not possible to make any form of definitive statement on the potential health impacts of ecigarettes unless the most fundamental form of eliquid is used as a control against the results from any other eliquid.

I remain entirely open to the findings of this study, and indeed, the possibility of harmful effects as a result of vaping, but in common with all other studies in this area, I find it troubling that a study such as this comments on gaping in general while not being predicated upon that which is vaping at it's most fundamental principles/constituents.

Competing interests declared: current tobacco smoker (however, not an electronic cigarette user)

RE: Absence of at least one appropriate control

tsussan1 replied to pearsek on 10 Feb 2015 at 17:58 GMT

This is a very valid point, and this is a limitation of our current study. We used a "cigalike" rather than a vaping device, which limited our ability to customize the eliquid. As a result, we cannot say what ingredient(s) in the e-cig are responsible for effects that were observed. We did a couple experiments with both traditional flavor and menthol flavor, and observed comparable results. So whatever is responsible is shared by both e-cigs. My guess is that nicotine is a significant contributor to the altered immune response, but there could be other components as well.

No competing interests declared.