Cigarettes. Roll-your-own tobacco. Smokeless tobacco. Cigars. Cigarillos. Pipe tobacco. Electronic cigarettes. Gels. Water pipes. The evolution of nicotine delivery systems has raised as many new questions for public health as it has brought new products to market. But none is more controversial than e-cigarettes.

The ongoing debate over the public health implications of e-cigarette use is full of passion. Some argue that e-cigarettes could be the beginning of the end of smoking in the U.S. Others claim e-cigarettes may erase the hard-won progress achieved over the last half-century in reducing nicotine and tobacco addiction.

The Family Smoking Prevention and Tobacco Control Act (Tobacco Control Act) of 2009 gave the U.S. Food and Drug Administration the power to oversee the manufacture, distribution, and marketing of tobacco products. The FDA currently regulates cigarettes, cigarette tobacco, roll-your-own tobacco, and smokeless tobacco products, but the 2009 law enabled the FDA to further expand its oversight to additional tobacco products. It has been studying the issue for several years and issued a proposed rule in 2014.

The final rule issued today brings previously unregulated e-cigarettes, cigars, hookah tobacco, and pipe tobacco, under FDA authority. The rule prohibits retailers from selling these products to people under age 18, and allows the FDA to evaluate manufacturers’ claims, evaluate the design and ingredients, and communicate potential risks. Further, it also requires manufacturers to demonstrate that products that went on sale after February 15, 2007 meet public health standards and receive FDA marketing authorization. The backdating of the rule to 2007 for e-cigarettes and certain cigars faces a challenge in legislation now moving in the U.S. House.

To properly understand the public health debate over e-cigarettes, it’s important to understand exactly what e-cigarettes are. E-cigarettes are battery-powered devices that aerosolize nicotine and other additives such as flavors. Heat is used to turn the e-cigarette liquid into an aerosol that is then inhaled by users, an action known as vaping. E-cigarettes do not contain tobacco, which is associated with exposure to harmful carcinogens.

This is precisely why e-cigarette advocates claim that e-cigarettes are a safer alternative to cigarettes. Many e-cigarette supporters also say these devices are helping thousands of regular smokers quit. This cessation argument is compelling because after decades of research, there is high awareness in the U.S. and globally about the serious health risks associated with smoking.

Conflicting Reports On Safety

The Centers for Disease Control and Prevention reports cigarette smoking is responsible for approximately 480,000 deaths per year in the U.S., which works out to about 1,300 deaths per day. Vaping proponents argue this number could be reduced if smokers were using e-cigarettes instead. This argument gained additional momentum late last year when Public Health England, a government agency in Britain, released a report in August stating that vaping is substantially safer than tobacco. However, it was later shown there were potential conflicts of interest with the research funding and that several authors of the study were paid advisors for e-cigarette industry.

There also are studies that point to the potential danger and public health risks of e-cigarettes. A 2009 FDA study found diethylene glycol, a toxin found in antifreeze, in some e-cigarette brands. A more recent study by Harvard University researchers found diacetyl, a flavoring chemical linked to respiratory disease, was present in 39 of 51 e-cigarette flavors tested. Two more compounds that pose potential respiratory hazards, acetoin and 2,3-pentanedione, were also found in e-cigarette liquids.

While both sides stake claims to support their argument, the reality is that there are few definitive answers when it comes to the public health impact of e-cigarettes. There are hundreds of studies and decades of research on tobacco and combustible cigarettes. That’s why most U.S. citizens understand and acknowledge that smoking causes cancer, heart disease, and lung disease. By comparison, research on e-cigarettes is very much in its infancy. After all, e-cigarettes were invented in 2003 in China and only introduced to U.S. and European markets in 2007.

Another problem facing researchers is the abundance and variation of e-cigarette products. A 2014 study identified more than 460 brands and nearly 7,800 flavors of e-cigarettes, and found that 10 brands and approximately 240 flavors were being introduced each month. Different brands and flavors contain a wide range of chemical substances and nicotine levels in their aerosols, and these levels may not match what’s on the product labels. These variations complicate research and are an obstacle to definitively answering questions.

A further complicating factor noted by a 2014 study is the lack of uniform, validated analytical methods to measure the chemicals released by vaping. All of these points illustrate why there is currently a substantial hole in that needs to be filled related to e-cigarette research.

Acknowledging Uncertainties and Evaluating Risks

The knowledge gap surrounding e-cigarettes is both medical and behavioral. Are e­­-cigarettes indeed safer (i.e. healthier) than cigarettes? Is vaping a viable solution for those trying to quit smoking? What will be the health impact to an individual of inhaling e-cigarette aerosol for many years? What is the impact of second-hand e-cigarette smoke? Or, do e-cigarettes attract non-smokers and serve as a gateway to trying cigarettes or other tobacco products?
Unfortunately, the unsatisfying answer to all of these questions is the same — we don’t know yet.

What we do know is more research is needed to answer these questions definitively. We also know data shows e-cigarette use among middle and high school students has grown substantially, tripling from 2013-2014, according to data from the National Youth Tobacco Survey. Our history tells us that many long-time smokers started as adolescents and continued the habit later in life.

Given what we know today about cigarettes’ impact on public health, and the progress that’s been made reducing cigarette use among teens, it only makes sense to raise serious concerns over e-cigarettes. With so many unknowns about the long-term health implications of e-cigarettes, the question for today is simple: are we willing to risk enabling another generation of smokers (or vapers) before we know the real effect?

The FDA’s new regulatory authority will propel the research community farther and faster in our efforts to close the knowledge gap. For example, at non-profit Battelle, our Public Health Center for Tobacco Research just installed our first Research-Grade Electronic Cigarette (REC), a unique laboratory device that mimics the aerosol production of commercial e-cigarettes. For the first time, we hope to accurately control laboratory tests to understand how product design and operating conditions influence a vaper’s exposures to toxic chemicals.

A study published last year by a Battelle researcher demonstrates why we can’t afford to waste time. The researcher found that almost half of pregnant women surveyed did not think electronic cigarettes contain nicotine or know that the devices can be addictive. About half also believed e-cigarettes would be less harmful to their fetuses than traditional cigarettes, a fact that has never been determined.

Let’s close the gap. The FDA’s regulations will play an important role in shaping the e-cigarette conversation now and moving forward, but it’s up to all of us in the research and academic communities to propose and execute the necessary studies to provide answers to these questions.