Table 1 reports awareness, ever use, and current use of ENDS and other novel and alternative tobacco products overall and by cigarette smoking status. Table 2 reports ever and current use of ENDS and current smoking by demography. Table 3 reports the adjusted associations between cigarette smoking status, other combustible tobacco use, and other non-combustible tobacco use with ENDS use. A detailed summary of the sample and reference population demographics and ENDS use by demography for emerging adults (18–24 years) and adults over 25 years old can be found in the supplemental document.
Awareness and use of electronic nicotine delivery systems (ENDS)
Overall, 91.9 % of USA adults had heard of ENDS. Our study estimated 14.9 % of USA adults have ever used ENDS and 4.9 % were current users. Use was substantially higher among current cigarette smokers compared to former and never smokers. Among current cigarette smokers, the odds of ever (OR = 21.4, 95 % CI = 16.5, 27.8) and current use (OR = 29.7, 95 % CI = 17.3, 51.0) of ENDS were substantially higher than for never smokers. Of those who have ever tried ENDS, 57.7 % (95 % CI = 53.7, 61.5) were current cigarette smokers, 25.3 % (95 % CI = 22.0, 28.9) were former smokers, and 17.0 % (95 % CI = 14.0, 20.6) were never smokers.
Ever and current use of ENDS is highest among young adults, particularly 25–34 year olds; those with some college education; those with less than a high school educational attainment; those with only fair or poor perceived health; and those with a non-heterosexual orientation. Young adults (25–34 years old) were more likely (OR = 1.7, 95 % CI = 1.0, 2.9) and those with a college degree were less likely (OR = 0.5, 95 % CI = 0.3, 0.7) to be current ENDS users. Adults with incomes between $40,000 and $60,000, $60,000 and $85,000, and greater than $100,000 had lower odds of current ENDS use (ORs = 0.3–0.6). Current ENDS use was less likely among those reporting good or better perceived physical health (OR = 0.5, 95 % CI = 0.3, 0.6), although this association was non-significant when controlling for cigarette smoking (AOR = 0.72, 95 % CI = 0.49, 1.05). Sex, race/ethnicity, presence of children in the home, and USA Census region were not associated with ENDS use in bivariate analyses. Sexual orientation was not associated with current ENDS use, though an association was observed for ever use. Non-heterosexual adults had higher odds (OR = 1.9, 95 % CI = 1.4, 2.6) of ever using ENDS. This association remained significant when controlling for smoking status (AOR = 1.8, 95 % CI = 1.2, 2.6).
Awareness and use of other tobacco products
In 2014, an estimated 16.6 % (95 % CI = 15.6, 17.6) of USA adults were current cigarette smokers and 27.6 % (95 % CI = 26.3, 28.9) were former cigarette smokers. We observed high awareness of other combustible tobacco products (Table 1), and nearly two-thirds (62.3 %, 95 % CI = 60.9, 63.8) of USA adults were ever users and 21.6 % (95 % CI = 20.4, 22.8) were current users of any combustible tobacco product. Use of these other combustible products varied by cigarette smoking status. Nearly one-third of all respondents reported ever using LCCs. Ever use of LCCs was more likely among current or former cigarette smokers, and current users were more likely to be current cigarette smokers. More than one in ten respondents has ever used hookahs, with use being higher among current and former cigarette smokers. Few adults reported current hookah use (1.2 %). Approximately one-quarter of respondents have ever smoked large cigars, with ever use being more common among former cigarette smokers. Current use of large cigars was reported by few adults (1.8 %). Whereas USA adults reported very high awareness of traditional smokeless tobacco (93.8 %), their awareness of snus and dissolvables was comparatively low (59.7 and 40.6 %, respectively). Nearly one-fifth of USA adults (17.9 %) have ever used traditional smokeless tobacco, and 2.1 % are current users. Snus use was less prevalent, with 4.0 % reporting ever use and only 0.3 % reporting current use. Dissolvables were the least prevalent non-combustible tobacco product examined in this study; only 1.1 % of USA adults reported ever using the product. Current use of dissolvables was too low to obtain reliable estimates with our sample. Non-combustible tobacco use was more prevalent among current and former cigarette smokers compared to never smokers. Current cigarette smokers (OR = 2.9, 95 % CI = 2.3, 3.5) and former smokers (OR = 3.2, 95 % CI = 2.7, 3.8) were more likely to ever use traditional smokeless tobacco than never smokers. Current smokeless tobacco use was greater among current cigarette smokers (OR = 2.5, 95 % CI = 1.5, 4.2) and former smokers (OR = 1.7, 95 % CI = 1.0, 2.9). Regarding snus, ever use was several times greater among current cigarette smokers (OR = 9.0, 95 % CI = 5.9, 13.8) and former smokers (OR = 3.9, 95 % CI = 2.5, 6.2) than never smokers. Similar associations with smoking status were observed for current use of snus use and ever use of dissolvables.
Associations between ENDS use and other tobacco use
Adjusting for other tobacco use, current smokers had nearly 18 times greater odds of ever use of ENDS and nearly 23 times the odds of current use of ENDS than did never smokers (Table 3, Model 1). Former smokers had twice the odds of ever ENDS use and 3.5 times the odds of current ENDS use as never smokers. These associations held and, in fact, were stronger, when statistically controlling for demographic and health status differences (Model 2). Other combustible and non-combustible use was also predictive of ENDS use. Ever use of any other combustible tobacco products (namely, LCCs, large cigars, and hookahs) was associated with 3.9 times greater odds of ever ENDS use than never use of these other combustible products. Ever users of non-combustible tobacco products (namely, smokeless tobacco, snus, and dissolvables) had 1.5 times greater odds of ever ENDS use than never users of these non-combustible tobacco products. Other combustible tobacco use was also predictive of current ENDS use. Adjusting for smoking status and non-combustible tobacco use, current users of non-combustible tobacco products had 4.4 times the odds and former use was associated with 1.8 times greater odds of current ENDS use than never users of these alternative combustible products. There was no statistically significant association between non-combustible tobacco product use and current ENDs use. These patterns of findings also remained and effect sizes undiminished after statistical adjustments were made for the demographic and health status covariates. After adjusting for other tobacco use and other covariates, sex, age, race/ethnicity, income, USA region, and perceived health status were significantly associated with ever use of ENDS and/or with current use of ENDS.
The findings from the logistic regression models are suggestive of high rates of dual use of ENDS and conventional cigarettes. Of those who were current ENDS users, 68.0 % were current cigarette smokers, 19.7 % were recent former smokers (quit within past 5 years), 2.3 % were non-recent former smokers (quit more than 5 years ago), and 10.0 % were never cigarette smokers (Fig. 1). Among current ENDS users, 21.0 % were current users of any alternative combustible tobacco product (namely, LCCs, large cigars, and/or hookah) and 75.1 % were current users of any combustible tobacco product (namely, LCCs, large cigars, hookah, and/or cigarettes).