Just putting it here:
https://www.mirror.co.uk/news/health/worlds-first-study-reveals-truth-34719574
We really don't know the full long term effects yet. It takes even cigarettes decades to kill, but they eventually do. 15 years is not that long, let's see in another 15 years.
But all of this is irrelevant to me - I choke and cough uncontrollably when exposed to that crap, and get lung, throat, and nose irritation for a day or two if exposed to a lot of it. Smoke is a lot worse of course, but with smoke you can at least escape it usually. I'm sure I'm not the ony one - many of my friends cough a lot after a night out - they just don't realize it's because of what they've been second-hand breathing.