We don't know yet. But besides the nicotine addiction, there are other components in the vapor which we have no long-term data on, because it's just so new. But we know that there are components in the vapor that are harmful to your health, and nicotine itself is cardiotoxic, so there's that [1].
We do however have studies showing that vaping can be implicated in lung cancer [2].
I can only answer anecdotally from my personal experience but: frequent coughing while not vaping, chest pain, very obviously reduced cardiovascular capacity and increased fatigue during my workouts.
Your body has no mechanism for purging oil residue from your lungs. The frequency at which vape users would be flooding their lungs with those vaporized oils was akin to someone starting out as a pack a day heavy smoker.
Tar as I understand it does break down very slowly over time but many smoke at a greater rate than it can be broken down and smoke itself is a worse irritant than oil vapor.
