This September 25, 2013 photo illustration taken in Washington, DC, shows a woman smoking an 'Blu' e-cigarette (electronical cigarette). The National Association of Attorneys General on September 24, issued a letter urging the US Food and Drug Administration to clamp down on the fast-growing e-cigarette market, saying manufacturers are enticing teenagers to smoke with cartoon characters, television ads and bubble-gum flavors. AFP PHOTO / Jim WATSON (Photo credit should read JIM WATSON/AFP/Getty Images)

The debate over e-cigarettes has been heating up. Are the smokeless, battery-powered, nicotine-dispensing devices a gateway to smoking for young people or a helpful way for smokers to quit? Public health experts can be found on both sides of the debate.

An article in the New York Times on Feb. 22 cited two leading figures, Dr. Michael Siegler from Boston University and Dr. Stanton A. Glantz from the University of California, San Francisco. Dr. Siegler maintains that e-cigarettes, "could be the end of smoking in America," while Dr. Glantz contends that not only could they lure children into smoking, but they also could keep adults hooked on the habit. One problem with this debate is that there has been insufficient evidence to confirm or deny either of these claims.

Evidence Lacking that E-Cigs Help Smokers Quit

That is beginning to change. One small study reported in JAMA Internal Medicine on March 24 found that e-cigarette use by smokers was not followed by greater rates of quitting or by reduction in cigarette consumption one year later. This finding appears to support Dr. Glantz's concern. Although the authors acknowledge several limitations to their study, they argue that, "regulations should prohibit advertising claiming or suggesting that e-cigarettes are effective smoking cessation devices until claims are supported by scientific evidence."

Risks of Liquid Nicotine

Even more troubling than the lack of significant evidence in support of opposing claims about the risks and benefits of e-cigarettes is the harm that can be caused by the liquid nicotine used in the device. Another article in the New York Times, which appeared on the same day the JAMA research was published, reported on accidental poisonings, especially among children, and cases involving harm to adults. In its liquid form, nicotine is a powerful neurotoxin that can be absorbed through the skin. The Times article cites toxicologists who warn that liquid nicotine poses a significant risk to public health.

What, if anything, should be done to minimize the risks of harm, especially to children? Would it be sufficient to require warning labels on the containers of liquid nicotine available for sale?

Some producers are already using such labels voluntarily, but apparently that has not been successful in protecting adults or children from the harmful accidents that have occurred. The FDA does not (yet) regulate e-cigarettes; the Times article says the agency plans to regulate but has not disclosed details. Given the many years that elapsed before the FDA began to regulate tobacco products in 2009, it may be some time before the agency has sufficient empirical evidence to justify its intrusion into the marketplace for these new products.

More Guidance Needed

At the very least, we need public health announcements about the dangers of liquid nicotine -- both when the product is inhaled and when it comes into contact with skin. One woman was admitted to the hospital with cardiac problems when her e-cigarette broke while she was in bed. To help in preventing inadvertent use by children, the childproof caps commonly used for all sorts of medications and household products are an easy fix. But beyond those initial steps, it remains unclear what else is warranted from a public health standpoint. Although commercial enterprises detest government regulation, the CEO of an e-cigarette company was quoted in the March 24 Times article as saying, "Honestly, we kind of welcome some kind of rules and regulations around this liquid."

A principle of public health ethics, known as the precautionary principle, holds that, "when an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically" (Staff, Science and Environmental Health Network, Jan. 26, 1998, Wingspread Conference on the Precautionary Principle). This rather formal way of saying "better safe than sorry" is a helpful warning, but fails to give clear guidance.

The options for a regulatory agency range from merely requiring warning labels to limiting what advertisements for a product can say to banning it altogether from the marketplace. Since the last option is highly unlikely in the case of liquid nicotine, we are left to ponder the best way to prevent harm to children and adult users.

It will be interesting to see where the FDA comes down on the issue. In the meantime, those who use e-cigarettes do so without sufficient scientifically-based guidance.