User pathways of e ‐ cigarette use to support long term tobacco smoking relapse prevention: a qualitative analysis

Background and aims E ‐ cigarettes are the most popular consumer choice for support with smoking cessation in the United Kingdom. However, there are concerns that long ‐ term e ‐ cigarette use may sustain concurrent tobacco smoking or lead to relapse to smoking in ex ‐ smokers. We aimed to explore vaping trajectories, establishing e ‐ cigarette users ’ perspectives on continued e ‐ cigarette use in relation to smoking relapse or abstinence. Design Qualitative longitudinal study collecting detailed subjective data at baseline and ~12 months later. Setting United Kingdom. Participants E ‐ cigarette users ( n ¼ 37) who self ‐ reported that they had used e ‐ cigarettes to stop smoking at baseline. Measurements Semi ‐ structured qualitative interviews (face ‐ to ‐ face or telephone) collected self ‐ reported patterns of e ‐ cigarette use. Thematic analysis of transcripts and a mapping approach of individual pathways enabled exploration of self ‐ reported experiences, motives, resources, and environmental and social in ﬂ uences on vaping and any concurrent tobacco smoking. Findings Three broad participant pathways were identi ﬁ ed: ‘ maintainer ’ (e ‐ cigarette use and not smoking), ‘ abstainer ’ (neither smoking nor using e ‐ cigarettes), and ‘ relapser ’ (dual ‐ using, or relapsed back to tobacco smoking only). In each pathway, individual experiences with vaping nicotine appeared to play an important role and appeared to be related to psychological and social factors. A social context supportive of vaping was important for the maintainers, as was a belief in the need to overcome nicotine addiction for the abstainers, and dislike of the ‘ vaping culture ’ expressed by some in the relapser group. Dual ‐ users held beliefs such as a need for cigarettes at time of acute stress that af ﬁ rmed dependence on tobacco. Conclusions In a sample of UK e ‐ cigarette users who report having used e ‐ cigarettes to quit smoking, a social context that supports continued vaping was perceived to be helpful in preventing relapse to smoking.


INTRODUCTION
In the United Kingdom (UK), vaping nicotine is mainly confined to smokers or ex-smokers [1], and e-cigarettes are the most popular consumer choice to assist quitting tobacco smoking [2]. There is support of vaping for smoking cessation by Public Health England [3] and health advisory bodies [1,[4][5][6], and clear regulation permitting use of e-cigarettes by adult smokers [7] but limiting advertising [8] and restricting access for young people and never smokers [9]. This is in contrast to other countries, where the regulatory environment has been less clear, and recent policy has taken a stricter prohibitory position [10], with potential consequential outcomes for smoking relapse prevention. Although long-term e-cigarette use as a substitute to tobacco smoking remains controversial due to unknown health harms, there is strong medical consensus that stopping smoking for good is the most efficacious health behaviour change that smokers can make in avoiding future cancer risk [11].
Our previous cross sectional data, from wave 1 of this study, demonstrated in-depth views and experiences of switching from tobacco smoking to e-cigarette use, suggesting that e-cigarette use might be a viable long term substitute for smoking, through meeting physical, psychological, cultural, social, and identity-related aspects of tobacco addiction that some ex-smokers struggle to overcome [12]. This exploratory work also suggested that 'lapses' in the context of switching need not result in full blown smoking 'relapse' [13]. Longitudinal analysis of survey data from other sources has suggested that e-cigarette characteristics and behaviours impact on relapse status [14]. In this study, we report longitudinal qualitative follow-up data (wave 2) to establish detailed trajectories over time.
Theoretically, our focus is integration of behaviour change maintenance, across psychological and social influences. Kwasnicka et al. [15] provide an organising structure, with themes related to behaviour maintenance motives, self-regulation, resources, habits, environmental, and social influences; a theoretical approach applied in previous studies of smoking trajectories [16]. We foreground a 'pathways' narrative approach to understanding behaviour over the life course. This assumes a human drive to maintain congruence in identity self-concept over time, externally observable via behaviour [17].
In this article, we sought to understand user patterns of e-cigarette use and long-term smoking abstinence by exploring the research question: 'what is the continued experience of e-cigarette use over time in the context of either tobacco smoking abstinence or relapse?' Qualitative longitudinal data can illuminate nuances in individual trajectories though switching to e-cigarette use. This might inform understanding of long-term patterns of behaviour that best support complete tobacco cessation.

Design
We used a qualitative longitudinal study design, repeating in-depth interviews at baseline and 12 month follow up.

Participants
A purposive sample of 40 UK e-cigarette users were initially recruited by responding to social media adverts for wave 1 data collection, matched by gender and age to a sampling frame of demographic characteristics from a representative sample of UK quitters (see [12]). Following ethical approval (FMH Reference:2017/18-106), follow-up data were col-lected~12 months later. A total of 37 participants completed follow-up interviews (response rate ¼ 93%). One person declined for personal reasons, and two were not contactable. Semi-structured qualitative interviews were conducted between March and May 2018.

Procedure
All participants gave written consent for interviews (faceto-face or telephone). Semi-structured guides took a narrative approach to initially review baseline reports (T1) (a 'pen portrait' of their narrative was discussed), then focusing on self-reported patterns of e-cigarette use over the last 12 months approximately (range 12-19 months, with average follow up time 14 months). Participants described devices used and nicotine e-liquid flavours and strengths, including changes over time. Participants described any experiences of lapse or relapse to tobacco smoking, reflecting on future intentions and identity-related aspects of e-cigarette use (see Supporting information, Data S1). Interviews were transcribed verbatim and anonymised. Participant codes used for quotations refer to age and gender at baseline (e.g. '24F' for 'female aged 24'). Quotes are verbatim but edited for brevity.

Analysis
Transcripts were thematically analysed [18] case-by-case by CN and EW. NVivo 12 software assisted analysis. Analysis was discussed at regular meetings, with anomalies agreed by consensus. Individual case summaries were updated from baseline, and a pathways diagram was plotted to illustrate participant trajectories.

RESULTS
Participants' age at follow up interview ranged from 22 to 71 (mean ¼ 42, SD 14.317). Baseline characteristics are reported elsewhere [12] but also summarised in Table 1, grouped by the three trajectories reported below. At T1, 28 participants were using e-cigarettes and abstinent from tobacco (16 had reported lapses), six participants had relapsed (five 'dual-using' both tobacco and e-cigarettes), and three were no longer either using e-cigarettes or smoking tobacco. At T2 follow-up, patterns of use remained reasonably consistent; 3/28 (9.7%) who were abstinent at T1 had relapsed by T2. Overall 8/37 had relapsed since trying to quit smoking by using e-cigarettes (21.6%) (Fig. 1).
We identified three trajectories of long-term e-cigarette use: maintainers, abstainers, and relapsers (Table 2).
Maintainer pathway (using e-cigarettes and abstinent from tobacco n ¼ 23/37) Most people who were using e-cigarettes and not smoking at T1 maintained that pattern at T2 (22/28, 79%). Reasons for continuation of e-cigarettes, as per T1, included maintenance motives such as replication of smoking, identity congruence, pleasure, and perceived health benefits [12]. Facilitative resources, including practicalities (e.g. cost, accessibility), also supported maintained smoking abstinence. Ongoing social connectedness facilitated through e-cigarette use was a key theme.   Abstainer pathway (abstinent from both n ¼ 6) Of the six people who reported neither e-cigarette use or smoking at T2: three had maintained abstinence from both Pathways of vaping 5 over time, and three had moved from e-cigarettes and not smoking to abstinence from both.

Cessation of e-cigarettes
One participant, who had remained abstinent from both between T1 and T2, described quitting e-cigarettes as an unintentional process; 'It's faded away of its own accord' (62F). At T1, she used her e-cigarette once a month in a specific social situation. At T2, she had only vaped once in several months: I absolutely wouldn't get rid of the e-cigarette … I use it a lot lot less though than the sort of once a month occasion.
What sets this person apart from others in this group is that she never intended to quit e-cigarettes, feeling that her addiction to nicotine and smoking was deeply ingrained. The reduction to nominal use had been surprising. The rest of the abstainers had always intended that e-cigarette use would be for smoking cessation, as other methods had not worked for them, eventually aiming to quit nicotine altogether. These participants were motivated to quit because they were uncomfortable with nicotine dependence: It wasn't like I was, there were times when I enjoyed it (vaping), when the novelty of it was quite interesting and fun and like, you know, but ultimately it was a substitute.

Identity change
One participant discussed lifestyle and image changes since T1, triggering e-cigarette cessation:

I've kind of changed myself in the way I see myself. I would say I've changed my style as well, like the way I dress has changed. So maybe I've reinvented myself in a way and taken smoking and vaping out of that image (28MT2)
At T2, in contrast to the maintainer group, the abstainers did not appear to be any more reassured about the health risks of e-cigarettes than they were at T1:

I'm not really sure how safe they are to be honest. I don't think I'm any more knowledgeable about it than I was last time. (26 M)
Some abstainers no longer felt the urge to smoke. The data were supportive of an identity change:

It's not like I'm consciously thinking I can't smoke because I'm here. It's just that I don't want to, like I think a lot of it is seeing yourself as a non-smoker and like wanting to make that change (22F) Brief tobacco lapse
Despite the abstainers reporting no desire to smoke again, three participants reported a brief tobacco lapse, since T1, after they had quit both e-cigarettes and smoking. One participant had a one-off lapse triggered by stress and one had a purposive lapse. Both these participants found smoking disgusting, reaffirming their quit:

I was like oh I'll just have a puff but then I'd have a puff of a cigarette and it would totally gross me out, it tasted horrible. I think because I hadn't had it for so long, I wasn't used to it anymore so it just made me feel sick. (22F)
The other participant had experienced a negative significant life event. He had permissively lapsed a couple of times as a way of dealing with stress. He minimised this lapse by compartmentalising it:

in September I threw away the cigarettes, I have lapsed a couple of timesit's always when I go and see my (family member) and it's just the feeling that I need something external because I can't really sort of deal with the situation, but it's not like, I wouldn't say I was smoking, I would say I was using, my … dependence on nicotine and cigarettes to deal with a very specific situation (36 M)
By allowing himself these lapses he was reinforcing his belief that he needed smoking in some situations. He felt in control of the lapses for the moment but did not have the same confidence that the others from this group displayed for long term abstinence.

Strategies to avoid lapse and relapse
Although nearly all the abstainers had achieved abstinence from smoking by using e-cigarettes, most commented that they would not vape again to avoid tobacco lapse or relapse. Instead, they planned to use other strategies:

It's kind of talking to myself and just say I don't need it, you know and I think I know that if I did smoke, like the taste would just make me sick now … I just keep hold of that feeling and that idea and it helps. (22F)
There was a sense that for these participants, using e-cigarettes again to avoid smoking relapse might signify failure. In addition, these participants had got rid of their e-cigarette devices: Relapser pathway (dual using or smoking only n ¼ 8) At T1, only one participant had fully relapsed to smoking; she remained smoking only at T2 (but had had a period of abstinence between T1 and T2). Two participants who were dual using at T1 remained dual using at T2. Three people who were vaping only at T1, and two people who were dual using at T1, had fully relapsed to smoking and were not using an e-cigarette at T2. Relapsers were, on average, younger in age than abstainers or maintainers (Table 1).

Reasons for relapse
Smoking triggers. In most cases participants experienced more than one smoking trigger simultaneously. Three participants discussed intolerance to e-cigarettes as contributing to their failed quit attempt. The participants had tried various different set-ups to try and resolve the issue, but these had not worked: When I finished one of the juice flavoured stuff I got, I went onto a different one and it made me cough and splutter loads and I kind of just fell out with it … R: Okay so you stopped using that and bought tobacco cigarettes instead? Yes. (25 M) Another trigger relating to e-cigarette function was the device breaking. Other than that, the other triggers mentioned were similar to triggers discussed by tobacco quitters using other methods. These included stress, alcohol use, or being in a social context of other smokers: Attitudes toward vaping. Most triggers described by relapsers had also been faced by the maintainers, but had not resulted in relapse for them. The specific attitudes communicated by the relapsers were qualitatively different compared to those who had continued vaping only: Future intentions: uncomfortableness with vaping long-term. Unlike most of the maintainers, at T1, six out of the eight relapsers stated that they eventually wanted to quit vaping following successfully quitting smoking. They were uncomfortable with nicotine addiction, feeling that vaping should only be used as a smoking cessation aid towards quitting nicotine completely. Like some of the abstainers, the relapsers were uncomfortable with a 'grazing' pattern of e-cigarette use. They felt that frequent vaping compromised their quit attempt by continuing an addiction to nicotine:

I find one of the worst things about it is you don't know when to stop (27F)
Unsatisfied by e-cigarette. At T1, most of this group held similar views about e-cigarettes and nicotine cessation as the abstainers. However, at T2 they had not been successful in quitting either e-cigarettes or smoking. What set this group apart from the abstainers is that at T1 nearly all the relapsed group had discussed their enjoyment of smoking and felt that e-cigarettes did not compare favourably to tobacco cigarettes in terms of nicotine hit, taste, or feel. At T2, most participants still maintained that e-cigarettes were inferior to the smoking experience:

It doesn't quite hit the spot.(36F)
In addition, some of these participants held strong beliefs based on past experience that in times of stress they needed tobacco to cope: I'm just probably not going to have one again until something happens or sort of, almost triggers me to have it … I've done that for years and years and sort of where my brain is stressed, I'm going to have a cigarette. (21 M) Only one participant in this group had a different attitude. At T1, he had successfully quit smoking by using e-cigarettes (after several failed quit attempts using traditional methods), finding it to be an adequate replacement, and was intending to quit nicotine completely. Unfortunately, he had experienced intolerance to e-cigarettes that had triggered his relapse: You know my aim from the outset with vaping to get off the nicotine altogether and vaping as a tool was working brilliantly, with exception to that build-up of an intolerance.

If it hadn't have been for that, I've got no doubt whatsoever that I would have achieved what I was seeking. (44 M)
Not identifying with vape culture. For the relapsers, the 'culture' and identity of being an e-cigarette user were very different to the felt experience of belongingness described by maintainers. Instead of enjoying e-cigarettes, the relapsers felt that belonging to the 'vape culture'(defined as a community of people who vape), was not for them: I just really don't understand it (vape subculture). R: Have you ever been into any vape shops or anything at all? Yes I didone in (place name) R: Okay, and how did you find that? An experience. Yeah I don't know, the guys were so bizarre and smug because I didn't know what I was on about or what I was getting and they were blowing 'smoke' at me and doing all these tricks and I just didn't like it. (25 M) Views on health risks and benefits of e-cigarettes. At T1, many from this group were concerned of the health risks of e-cigarettes. At T2, some had maintained this view or seemed apathetic:

DISCUSSION
Using UK qualitative longitudinal data, we illuminate three key e-cigarette using pathways-the 'maintainer' pathway (e-cigarette use and not smoking), the 'abstainer' pathway (neither smoking nor using e-cigarettes), and the 'relapser' pathway (dual-using, or relapsed back to tobacco smoking only). We interrogated the trajectories to draw out individually influenced motives and habits, resources, environmental and social influences, mapping to Kwasnicka et al.'s integrated theory of behaviour change maintenance [15]. Through each of the pathways, individual experiences with using nicotine are critical, but these are heavily influenced by social factors, such as a supportive vaping context for the maintainers, or dislike of the 'vaping culture' expressed by some in the relapser group. Treating the data as narratives, we are able to understand the process of vaping over time and patterns of use that link through accounts of identity to tobacco smoking or quitting. For many, particularly perhaps the 'abstainer' group who have moved to quitting both e-cigarettes and tobacco, a natural progression towards abstinence is apparent, that may be likened to a 'maturing out' effect previously reported in other addictive behaviours [19]. This implies that smoking cessation by using e-cigarettes may be a process that evolves over time, as individuals disengage from a smoker identity, and might best be regarded as a positive step towards smoking cessation, rather than an instant switch [20][21][22]. Indeed, the gradual 'slide' toward abstinence that the data supports, and the behavioural processes of occasional tobacco lapses that serve apparently to negatively reinforce ongoing tobacco abstinence, suggest that a period of time allowing experimentation and adaptation of behaviour, integrating the new non-smoker identity, is necessary to fully switch from tobacco smoking to e-cigarette use. Previous studies of smoking cessation have similarly demonstrated how quitting can include elements of both spontaneity and preparation, that are especially pertinent in the context of e-cigarette use [23]. For the largest 'maintainer' group, continued e-cigarette use may be protective against smoking relapse, a positive long term-maintained behaviour, and is accepted as an integrated part of identity.
An alternative hypothesis, that using e-cigarettes may leave people vulnerable to smoking relapse through maintaining nicotine addiction [24], is a prevalent concern in other policy contexts. This view is contradicted by recent cohort data [25]. In our qualitative longitudinal data, we also observe some long-term e-cigarette users reporting experiencing a natural and easy reduction of dependence through reducing nicotine strengths over time, a reported reduction of cravings and tobacco lapse behaviour, and a belief that addiction to nicotine has waned.
The 'maintainers' may continue to use e-cigarettes long-term. They experience e-cigarettes as personally satisfying and enjoyable, and many also enjoy the social and identity related aspects of e-cigarette use, in a similar way to that identified by previous studies where e-cigarette use is presented as a positive social practice that opens up time and space [26]. Although evidence consensus reviews suggest that e-cigarette use is much less harmful than tobacco smoking [27,28], there is, as yet, no public health consensus on the health consequences of long-term use. Others within our sample, the 'abstainers', had moved to quitting both tobacco and e-cigarettes. For some people, continuing to use nicotine is neither desirable nor congruent with identity, and conceivably, this may be a pathway that others may choose to take over time. At present, there is no evidence-based advice on how to support people to stop using e-cigarettes, if that is their choice. There is a need for such advice, particularly in supporting people to avoid any possibility of relapsing back to tobacco smoking. Our data preliminarily suggest that strategies such as gradual weaning towards lower nicotine strength e-liquid may be successful for some people. Conversely, to remain on a pathway toward full tobacco abstinence, the qualitative data suggest a need to support e-cigarette users to switch to higher nicotine strength e-liquid during times of stress, if necessary, to avoid cravings and risking smoking relapse.
Most of the relapsers and abstainers shared similar attitudes over time that contrasted with the maintainers: that they should only use e-cigarettes as a temporary measure, they were uncomfortable with long-term nicotine use, and were suspicious of e-cigarette safety. The maintainers, conversely, were comfortable with nicotine use. They enjoyed e-cigarette use as a pastime and felt invested with a 'vaper' identity. They also saw e-cigarettes as much less harmful as smoking and felt supported by their social groups. Relapsers differed to both the abstainers and maintainers in that they were less motivated to quit-they enjoyed cigarette smoking, maintained a belief that cigarettes were necessary to cope with stress, and held more negative views about vape shops and vape culture that other groups saw conversely as a source of support. They were also of a younger age, on average.
Our findings are limited in that they are drawn from a small qualitative sample. Although the initial purposive sample reflected the general population of quitters, those from ethnic minorities and low socioeconomic groups are not well represented. It is also likely that the sample is skewed toward those most motivated to maintain smoking abstinence and most willing to share their experiences. However, a strength is the in-depth perspectives gleaned, allowing detailed exploration of individual trajectories of e-cigarette use behaviour over time. This provides robust experiential data and allows us to illuminate major patterns of use, suggest areas of need, and hypothesise support that may be necessary for long term smoking cessation.
To promote tobacco smoking relapse prevention, our findings suggest that supporting continued e-cigarette use, as reported by the 'maintainer' group, might be beneficial. E-cigarette users require frequently updated evidence-based advice on the relative safety of e-cigarettes in comparison to tobacco smoking. For dual users or those who occasionally lapse to tobacco, there is a need to tackle beliefs about dependence on tobacco and offer alternative strategies for triggers such as stress. For those who struggle to find a satisfying and effective e-cigarette set-up, there is a great need for support, perhaps from peers, who are a valued source of advice [29,30]. Particularly, there is a need for information about increasing or reducing nicotine strengths, to prevent cravings and cope with stressors, and advice on using different flavours to suit preferences and aid sustained cessation [31]. Those who eventually wish to quit e-cigarettes need evidence-based information about effective ways to do this, without increasing vulnerability to tobacco relapse.
In delineating three major pathways through e-cigarette use, our data demonstrate a clear role of e-cigarettes in smoking relapse prevention in the UK policy context. This suggests that policies supportive of vaping could be adopted by other jurisdictions concerned with smoking relapse. Once quit smoking, the majority pattern apparent in our data is a move towards exclusive, ongoing, e-cigarette use. For some, there is a move completely away from both smoking and e-cigarettes. For a minority, there are continued patterns of dual use or relapse back to tobacco smoking. Future research might focus on younger people who may be less motivated to 'mature out' of dual use or tobacco smoking behaviour. Health efforts need to prioritise intervention with this group, through targeting individual level beliefs and physical dependence needs, social level support, and cultural level reinforcement of reduced harm alternatives that might support complete smoking cessation.

Declaration of interests
C.N., E.W., and R.H. declare no competing interests. L.D. has provided consultancy for the pharmaceutical industry relating to the development of smoking cessation products.