Although combustible cigarettes (hereinafter referred to as cigarettes) continue to dominate the tobacco product market in the United States, the emergence and rapid growth of electronic cigarettes (e-cigarettes) in the past decade has led to a transformative change in the US tobacco market—a rapid increase in awareness and use of e-cigarettes among youth and adults that coincided with a decline in cigarette smoking.1–3 This transformation has been accelerated in recent years by the emergence of new generations of e-cigarettes, such as JUUL e-cigarettes (JUUL Labs).4,5 The exponential growth in e-cigarettes has prompted a renewed interest in the tobacco harm reduction approach, which aims to curb the smoking epidemic rapidly by encouraging smokers to switch to low-risk tobacco products such as e-cigarettes.6 The potential role that e-cigarettes may play in reducing the harm caused by tobacco is still the subject of heated debate.6,7
Although the long-term health effects of e-cigarettes are still unknown, growing evidence and consensus among scientists and researchers suggest that the short-term health risks of completely switching to e-cigarettes are substantially less than those of continued smoking for adults who are unable or unwilling to quit cigarette smoking. For example, a recent comprehensive review concluded that, for adult smokers, a complete switch to e-cigarettes would impose substantially less harm than continuing to smoke cigarettes,8 which remain the deadliest tobacco product.9 Despite the growing scientific evidence, whether the short-term relative health risks of using e-cigarettes compared with cigarette smoking have been accurately communicated to the public is unclear. Some researchers have voiced criticism that the dominant public health message in the United States still focuses on the absolute risks of using tobacco products rather than the relative health risks between low-risk products and cigarettes.10 Although the US Food and Drug Administration (FDA) has acknowledged that nicotine, which is highly addictive, is delivered through products that represent a continuum of risk,11 the FDA does not have active campaigns to communicate this message to the public. As such, the risk communication of different tobacco and nicotine products was largely left in the hands of tobacco industry, the e-cigarette industry, and the media.
Previous research has demonstrated that perception of risk plays a critical role in decisions to use tobacco.12 For example, studies have shown that concerns about the health risks are one of the most cited reasons to quit smoking among current and former smokers.13,14 Similarly, consumers’ risk perception about e-cigarettes and other new and emerging tobacco products may also play an important role in influencing how these products are used and who will use these products. For example, one of the common cited reasons for e-cigarette use is the belief that e-cigarettes are less harmful than cigarettes.15–17 A recent comprehensive review of consumers’ relative risk perceptions about different tobacco products found that, among e-cigarette users, most respondents perceived e-cigarettes as less harmful than cigarettes.18 In addition, studies have also shown that, in certain population groups, the perception of e-cigarettes as less harmful was associated with future use of e-cigarettes.19
Although research on the relative risk perception between e-cigarettes and cigarettes is growing, many studies tend to focus on perception at a specific point, in a specific geographic area, and among a specific subpopulation.18 Little is known about how the overall risk perception of e-cigarettes has evolved or changed over time. In addition, previous studies20 used different approaches to measure risk perception of e-cigarettes, making findings difficult to compare across studies and over time. In the present study, we examine whether and to what extent the perceived relative harm of e-cigarettes compared with cigarettes has changed during a 6-year period (2012-2017) in the United States. This study builds on previous research21 and uses data from 2 nationally representative surveys of noninstitutionalized US adults to examine the perceived relative harm of e-cigarettes compared with cigarettes and how the perception has evolved over time.