There's no proof of that. In fact there's still no proof to my knowledge that nicotine itself is harmful - to the contrary, it may have neuroprotective properties.
Nicotine itself is a deadly poison. MSDS: https://fscimage.fishersci.com/msds/96314.htm
"May be fatal if absorbed through the skin"
https://www.fishersci.com/shop/msdsproxy?productName=O172850...
...also for reference caffeine seems to be more than an order of magnitude more toxic than pure ethyl alcohol by weight.