Recent research shows that e-cigarettes may pose an increased risk of heart attack. A new study in the Journal of the American College of Cardiology has found that the substance used to flavor e-cigarettes can threaten the survival and proper functioning of human cells. The study’s author says the research refutes the common perception of vaping as a safe alternative to smoking regular cigarettes. The Food and Drug Administration said last year that vaping had increased nearly 80% among high schoolers and 50% among middle schoolers over the previous year.