“…While others, specifically funded by the tobacco industry, have consistently reported few adverse respiratory health outcomes in smokers transitioning to e-cigarette use [33] , [40] , [41] . It is worth mentioning that the mass marketing of e-cigarettes has been available for only 15 years, and not enough time has been given to provide long-term studies on the safety of e-cigarettes [42] . Furthermore, several studies on e-cigarettes were performed in vitro, and may not be directly comparable to clinical and or in vivo studies.…”