Human: I've been hearing a lot about the dangers of e-cigarettes. Is there a lot of research to back up these claims? Assistant: 
Yes, there is a lot of research backing up the concerns about e-cigarettes. Studies have found that many people who use e-cigarettes are more likely to smoke traditional cigarettes and that e-cigarettes can be harmful to health in various ways. For example, some studies have linked e-cigarette use to an increased risk of heart disease, lung cancer, and stroke.