# A longitudinal study of cotinine in long-term daily users of e-cigarettes



## Andre (1/12/16)

https://www.ncbi.nlm.nih.gov/pubmed/26804899
*A longitudinal study of cotinine in long-term daily users of e-cigarettes.*
Etter JF1.
*Author information*

*Abstract*
*BACKGROUND:*
It is not clear whether, in established vapers, cotinine levels remain stable or change over time.

*METHODS:*
We enrolled 98 exclusive users of e-cigarettes on websites and forums dedicated to smoking cessation and to e-cigarettes. We collected saliva vials by mail in 2013-2014 (baseline), and collected a second saliva vial eight months later (follow-up) in the same participants. Participants had not used any tobacco or nicotine medications in the previous five days. Cotinine in saliva was analyzed with liquid chromatography-mass spectrometry. Use of e-cigarettes, tobacco and nicotine medications was self-reported.

*RESULTS:*
All participants were former smokers, and 99% were using e-cigarettes daily. They had already been using e-cigarettes for nine months on average at baseline. The median cotinine level was 252ng/mL at baseline (quartiles: 124-421ng/mL) and 307ng/mL at follow-up (114-466ng/mL, W=0.9, p=0.4 for change over time). The median concentration of nicotine in refill liquids was 11mg/mL at baseline (quartiles: 6-15mg/mL) and 6mg/mL at follow-up (5-12mg/mL) (Wilcoxon signed rank test: W=5.2, p<0.001 for change over time). The median volume of e-liquid used per month was 80mL at baseline (quartiles: 50-130mL) and 100mL at follow-up (60-157mL, W=3.3, p=0.001 for change over time).

*CONCLUSION:*
In experienced e-cigarette users enrolled online, cotinine levels were similar to levels usually observed in cigarette smokers. Over time, these users decreased the concentration of nicotine in their e-liquids, but increased their consumption of e-liquid in order to maintain their cotinine levels constant.

Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Reactions: Like 2 | Informative 9


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## Silver (24/12/16)

Thanks @Andre
Only saw this now

Very interesting. So does this mean that the natural tendency for vapers to reduce the strength of their juice doesn't have much effect? Since they are typically consuming more ?

Could one argue then with the long term impact of flavour inhalation unclear that its probably safer to get ones nicotine through lower volume usage at higher nic strength?

Reactions: Like 1 | Agree 3


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## Lord Vetinari (24/12/16)

Silver said:


> Thanks @Andre
> 
> 
> Could one argue then with the long term impact of flavour inhalation unclear that its probably safer to get ones nicotine through lower volume usage at higher nic strength?


Interesting thought and of course the lower volume needed for the drug fix the better. But then there are those of us who pretty much vape for the flavorings and do a lot of zero liquids. So a whole new risk class emerges, the flavor only vapers.

Reactions: Agree 2


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## Andre (24/12/16)

Silver said:


> Thanks @Andre
> Only saw this now
> 
> Very interesting. So does this mean that the natural tendency for vapers to reduce the strength of their juice doesn't have much effect? Since they are typically consuming more ?
> ...


That has been my sentiment all along. From what I have read higher power is also not good. So, yes, high nicotine consumed at low power sounds the most sensible imho. Fortunately, MTL is making a comeback!

Reactions: Like 1 | Agree 2


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## Silver (24/12/16)

Mustrum Ridcully said:


> Interesting thought and of course the lower volume needed for the drug fix the better. But then there are those of us who pretty much vape for the flavorings and do a lot of zero liquids. So a whole new risk class emerges, the flavor only vapers.



Agreed @Mustrum Ridcully 
I wonder how many vapers who used vaping to stop smoking have reduced their nic to zero mg versus staying on low nic.


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## PSySpin (24/12/16)

This is what I found for cotinine on wiki https://en.m.wikipedia.org/wiki/Cotinine

It seems to have some positive effects

Reactions: Agree 2


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## Silver (24/12/16)

Andre said:


> That has been my sentiment all along. From what I have read higher power is also not good. So, yes, high nicotine consumed at low power sounds the most sensible imho. Fortunately, MTL is making a comeback!



Interesting this @Andre

Whatever happened to Dr Farsalinos' temperature studies. @Alex, have you found anything on your radars to this effect?

As to MTL making a comeback, that would be super. I just wish there were more great quality MTL alternatives readily available.

Reactions: Like 1 | Agree 2


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## Alex (25/12/16)

Silver said:


> Interesting this @Andre
> 
> Whatever happened to Dr Farsalinos' temperature studies. @Alex, have you found anything on your radars to this effect?
> 
> As to MTL making a comeback, that would be super. I just wish there were more great quality MTL alternatives readily available.



@Silver there is nothing new that I can find with regard to this study.

Reactions: Thanks 1


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