Effects of e-cigarettes, which youth are using more than ever before, unknown

So what is the latest on electronic cigarettes? The Federal Food and Drug Administration requested the National Academy of Sciences to engage in an extensive review of the scientific literature and issue a report about what the evidence shows regarding their use and health effects.

E-cigarettes have been available since 2006, so we are just really beginning to learn about them. It will take decades of e-cigarette use before we have a definitive idea about their long-term health effects on individuals and their broader effect on public health. It took decades to draw confident medical conclusions on the health effects of combusted tobacco. It will no different for e-cigarettes.

Millions of Americans use e-cigarettes and their use is especially escalating among youth. Their use in children and young adults now exceeds cigarette smoking. The prevalence rates in youth vary widely among studies; one study revealed that one-third of high school seniors have “ever-tried” e-cigarettes. Use is much greater among youth than for adults, and few adults begin using e-cigarettes who are not already using combustible tobacco.

The report determined that there is conclusive evidence that e-cigarettes contain nicotine and toxic substances that have the potential to adversely affect health. They also emit toxic compounds, particulate matter, and nicotine in indoor environments. The amount of exposure to the user and the amounts in the environment vary according to the particular device and e-liquid constituents. There is also conclusive evidence that completely substituting e-cigarettes for conventional cigarettes significantly reduces exposure to toxins and carcinogens.

There is substantial evidence that e-cigarette nicotine exposure can be comparable to cigarettes but possibly less addictive. There is also substantial evidence that e-cigarettes can induce acute injuries in the lining of arteries and more generally in other tissues but less so than conventional cigarettes.

Adolescents who use e-cigarettes are more prone to coughing and wheezing and exacerbations of asthma. E-cigarettes are capable of causing DNA damage that could lead to an increased risk of cancer with long-term use. It is generally felt that e-cigarettes cause less adverse short-term health effects and have the potential of causing less long-term adverse effects. But the long-term consequences are still unknown.

There is substantial evidence that e-cigarettes can lead youth and young adults to the use of combustible tobacco cigarettes. Conversely, there is only limited to moderate evidence that e-cigarettes are an effective cessation aid. Data on the comparative effectiveness to traditional FDA-approved cessation medications is insufficient.

There is limited evidence that e-cigarettes can improve lung function in asthmatic smokers and reduce execrations of COPD in smokers. There is no available evidence whether long-term e-cigarette use is associated with increased risk for respiratory illnesses, cardiovascular disease or cancer (either compared to combustible tobacco use or no tobacco use). There is insufficient evidence whether e-cigarettes affect fetal development and no evidence whether or they adversely affect pregnancy outcomes.

So, there is much we still don’t know, especially about the long-term health effects of e-cigarettes. Certainly, e-cigarettes will prove to be harmful, but probably less so than combustible tobacco. They appear to be a double-edged sword. If smokers transition to e-cigarettes, the benefit in reducing morbidity and mortality could be considerable. Yet if youth continues to embrace their use, we may find smoking-like behaviors normalized again; new generations addicted to nicotine, potentially at increased risk for chronic diseases and cancer and also prone to begin use of combustible tobacco products.

The net public health effect is unknown.