Can electronic cigarettes help smokers quit? Research is mixed, complicated by the fact that researchers have largely ignored a possible cause-and-effect relationship between e-cigarette and cigarette smoking.
But taking causality into account, e-cig use increases the probability that a smoker will try to quit, and e-cigs may help people quit over time, according to National Bureau of Economic Research’s Henry Saffer, Bentley University’s Dhaval Dave, City University of New York’s Michael Grossman, and CUNY PhD candidate Daniel Dench.
E-cigs are battery-powered smoking devices designed to look and feel like cigarettes. Because these cigarette alternatives don’t burn tobacco, people using them take in no tar or carbon monoxide, as they would smoking cigarettes. But e-cigs still transmit a vapor containing nicotine and other unhealthy chemicals.
Although e-cigs cannot be marketed as cessation aids, the adult use of e-cigs increased tenfold over six years, to 3 percent of all adults in 2016—during a decade in which adult smoking declined by almost a third, to 15 percent, in 2015. Yet it’s not clear whether this increase in e-cigs caused the decline in cigarettes. Researchers at the University of California at San Diego find that people using e-cigs were able to quit smoking at a higher rate than those who didn’t. However, researchers at the University of California at San Francisco reviewed 38 studies and argue that e-cig use was found to be associated with significantly less cessation among smokers.
Part of the problem is that causality can be hard to determine, write Saffer, Dench, Dave, and Grossman. They point out that causality could work in both directions, with e-cig and cigarette use mutually affecting each other. Or, some underlying, unobserved factor could be driving changes in demand for both products.
The researchers took on this issue by delving into data on e-cig and cigarette use from the July 2014, January 2015, and May 2015 waves of the Tobacco Use Supplement to the Current Population Survey (TUS), a data set sponsored by the National Cancer Institute and based on US Census Bureau surveys. In addition, they used price information from the Nielsen Retail Scanner data set, obtained from Chicago Booth’s Kilts Center for Marketing.
Saffer, Dench, Dave, and Grossman began with the choices and outcomes available to smokers. It’s up to a smoker to decide whether or not to attempt to quit, an action that could result in success or failure. Regardless of what the smoker decides, she could also wind up smoking less, the same, or more.
The researchers analyzed the data to determine how e-cig use affected each scenario. Causality between e-cig use and cigarette quit rates can go in either direction, or both may be determined by an unobserved third factor, but because e-cig prices and e-cig use are related (as prices rise, use falls), the researchers used e-cig prices as a logical stand-in for e-cig use, resulting in a cleaner estimate.
With this approach, the researchers find that e-cig use raised the probability that a smoker would try to quit, although most attempts still ended in failure. It also reduced the amount of smoking by those who failed to quit and those who didn’t try. Although the researchers find no conclusive evidence that e-cigs increased the likelihood of successfully quitting smoking, the results suggest that using them may “create a path toward cessation” over a longer period of time.
Saffer says that their study does find that more people who used e-cigs successfully quit smoking cigarettes than those who did not use e-cigs. However, the success rates weren’t significant enough to be conclusive—largely because the TUS data series spanned 2014–15, while quitting can take two or more years. That said, the results are still encouraging for people trying to kick a cigarette habit.
“In the worst case scenario,” the researchers conclude, “e-cig use reduces smoking by adults,” who cut down on cigarettes while using e-cigs.