The vascular effects are very similar to prior research on cigarette smoke. It's precisely the same initial effects thought to lead to heart disease in smokers.

The vascular effects are very similar to prior research on cigarette smoke. It's precisely the same initial effects thought to lead to heart disease in smokers. edit: You my have edited your comment while I was relying. The second of two sentences under Background (first section) mentions that this was a nicotine free study unlike earlier ones.