Americans are quitting smoking in higher numbers

The annual rate of people who quit smoking has hovered around 4.5 percent for years but in the 2014-15 Current Population Survey-Tobacco Use Supplement (CPS-TUS) survey the smoking cessation rate increased to 5.6. The 1.1 percentage point increase is statistically significant, representing approximately 350,000 additional smokers who quit in a 12-month period.

Shu-Hong Zhu, PhD, UC San Diego professor of Family Medicine and Public Health and director of the Center for Research and Intervention in Tobacco Control, and team published their findings in the British Medical Journal on July 26, 2017. Zhu attributes the increased cessation rate, in part, to national tobacco control media campaigns that began airing in 2012 and an increase in the popularity of e-cigarettes that spiked around 2014.

"Our analysis of the population survey data indicated that smokers who also used e-cigarettes were more likely to attempt to quit smoking, and more likely to succeed," said Zhu. "Use of e-cigarettes was associated both with a higher quit rate for individuals as well as at the population level; driving an increase in the overall number of people quitting."

Zhu and team examined the relationship between e-cigarette use and smoking cessation using data collected by the US Census CPS-TUS, a national survey of adults 18 years or older conducted to obtain information about changes in the country's use of tobacco products. It is based on the largest representative sample of smokers and e-cigarette users available, although it is not a randomized trial.

Survey participants were asked about their use of traditional cigarettes and e-cigarettes over a 12-month period. Researchers found that 65 percent of smokers who used e-cigarettes within the previous 12 months had attempted to quit smoking traditional cigarettes, compared to 40 percent of smokers who did not use e-cigarettes. Overall, 8.2 percent of smokers who used e-cigarettes successfully quit smoking traditional cigarettes, while 4.8 percent of smokers who did not use e-cigarettes were successful.

"The cessation rate among those who did not use e-cigarettes remained the same compared to previous years," said Zhu. "These data suggest that e-cigarettes play the role of a cessation tool."

Earlier studies have also looked at e-cigarettes as a cessation tool, and some have concluded that e-cigarette use did not aid smokers in quitting. A key finding in this analysis, said Zhu, is that in 2014-15 more people using e-cigarettes were doing so intensively. In fact, more than 70 percent of people who had successfully quit smoking recently were still using e-cigarettes daily, which may help prevent relapse, wrote researchers.

"People who use e-cigarettes are a self-selected group," said Zhu. "They may do better with e-cigarettes because they may already be motivated to quit. It is important to look at the entire population including users and nonusers to determine if the overall cessation rate went up or down."

This study did not address the long-term health effects of e-cigarette use. Rather, the study focused on whether e-cigarettes contributed to people's ability to quit smoking. The survey did not provide details about the type of e-cigarettes used nor if other smoking cessation tools, such as medications or pharmacotherapy, were simultaneously used. Clinical trials have shown that pharmacotherapy does help some individuals to quit smoking. However, in the years before e-cigarette use became widespread, the rates of smoking cessation among the entire population did not change significantly despite the promotion of pharmacotherapy, according to Zhu.

This study did not investigate if the use of e-cigarettes leads people to start smoking. However, the Centers for Disease Control and Prevention report recently reported that tobacco use among youth continues to decline rapidly while e-cigarette use increased during the same time period. The UC San Diego study focused on adults. It revealed that most e-cigarette users were already smoking cigarettes. Two percent of people who reported that they have never smoked cigarettes have tried e-cigarettes at some point.

"Other interventions that occurred concurrently, such as a national campaign showing evocative ads that highlight the serious health consequences of tobacco use and state tobacco control efforts, no doubt played a role," said Zhu. "But analysis of the CPS-TUS' most recent data presents a strong case that e-cigarette use contributed to an increase in smoking cessation at the population level."