Electronic cigarettes: the road ahead.

Electronic cigarettes (e-cig) are proliferating in the world's lucrative nicotine delivery market at an alarmingly fast pace. E-cig are aggressively marketed as an alternative to conventional tobacco cigarettes, although very little is known about the health consequences of e-cig use. Chemical analysis of e-cig vapor/liquid has shown that many toxicants and carcinogens present in cigarette smoke are also found, albeit generally in lower concentrations, in a wide range of e-cig products. Notwithstanding the presence of toxicants and carcinogens in e-cig products, the biological effects of exposure to these contaminants have not been determined in e-cig users. The ongoing research and future investigations on e-cig initiation, use, perceptions, dependence, and toxicity are expected to provide empirical evidence that can be used to inform the general public, scientific community, and regulatory authorities of the health risks/benefits associated with e-cig use. This information will help stimulate scientists in the field of tobacco research, as well as assist the regulatory agencies in making scientifically based decisions on the development and evaluation of regulations on tobacco products to protect the public's health. Finding the scientific underpinnings for the health risks/benefits of e-cig use can impact millions of people who are increasingly turning to e-cig as a replacement for or complement to conventional tobacco cigarettes.