I would be curious to compare this to smoking an actual cigarette to see if there is any difference. Inhaling any vapor/smoke that isn't meant for your lungs is going to cause damage and it would be neat to see a comparison between the two.
Anecdotal story time:
My grandfather who is currently 81, has been smoking since he was 12. He grew up in a very small town, and had 6 people in his graduating class other than himself.
Around January of this year, during a visit he seemed inquisitive as to the vaping device I was using. He still at this time was smoking 1.5-2 packs a day of roll-your-own cigarettes.
The reason he still was smoking so much is he has severe health issues from being legally blind from diabetes, and having extreme back pain since he returned from the service. In his hold age the only place he can sit and relax is this very old chair that sits on his porch that for whatever reason the angle on it relieves his back pain. He sits on that porch, smoking I would say 85% of his time, and the habit of playing with cigarettes while sitting there was the biggest factor.
After inquiring about my device and having me explain it to him he wanted to buy one right away and get on the e-cig bandwagon. I was skeptical as he has a whole multitude of health issues and if I were to switch him without consultation and something were to happen the guilt would be very great and I could not live with that.
I went with him to one of his visits to the V.A. and he brought up the subject of e-cigs to his doctor. We all had a conversation that pretty much came to the conclusion that continuing to smoke cigarettes wouldn't be any better than e-cigs, and there is always a chance that the e-cig could be worse but there was nothing definitive.
I was able to get him to transition to smoking 0% nicotine juice, with a higher PV/VG ratio (from what I've gathered online in smoker forums high VG juice tends to inflame those with asthma more than the PG). He did use nicotine patches for two weeks when he came off the cigarettes.
He slipped up and did smoke about 3 cigarettes during this transition, but starting the beginning of February he has been nicotine free and smoking the e-cig.
He recently had a lung test or something where they measure your 02 etc. He had said when he was smoking his 2 packs a day that his 02 was at 65% or so, and that it had gotten up to 78% at his last test.
Now I'm not a doctor and there are probably a billion variables that are unaccounted for, however he said that his breathing is much easier and doesn't have a hard time sleeping when it is hot and humid out as much as before. For him the switch seems to be working with regards to his lungs/breathing.
As far as other issues becoming more exacerbated because of this, only time will tell I guess.
He does want to quite completely, I suggested switching to sugar free candies or something to keep his oral fixation at bay while he sits in his chair. He seemed open to the idea, but like most smokers it really is a mental game and trying to get him to change his ways is pretty tough as he is a stubborn old man.