Utility and policy implications of e-cigarettes E-cigarettes could provide a safer source of nicotine for smokers to use instead of extremely harmful tobacco cigarettes,

allowing smokers to make the decision to attain the reinforcing effects of nicotine by other means. They may have benefits over common NRT products by addressing both the positive and negative reinforcing effects of nicotine and also providing some sensory and motor cues that may have become conditioned reinforcers. The studies in this thesis support that nicotine may play an important role in determining the subjective effects of e-cigarettes and their subsequent use, but highlights that taste and enjoyment factors also play an important role, and these factors may be negatively affected by higher levels of nicotine (Tucker, Bullen, et al., 2017a). Based on these findings, higher levels of nicotine in e-cigarettes may not be required for low-moderate dependence smokers to attain the positively and negatively

reinforcing effects of nicotine and, in fact, higher levels may be experienced as more aversive by low-dependent, first-time users and may discourage future e-cigarette use. This suggests

that lower nicotine levels may provide these users with the optimal balance of withdrawal symptom alleviation and taste and enjoyment factors to promote the transition from first-time trial use to experimental or potentially longer-term use of e-cigarettes. Educational campaigns may assist with this process. However it is important to note that the sample in these studies was predominantly young and male, with relatively low levels of dependence. It would be important to assess these trends in highly dependent smokers in order to determine whether the same increase in aversiveness with increasing nicotine content would be observed, whether the predictive model would remain significant, and which nicotine levels would be most beneficial in their decision to switch to e-cigarettes.

Another important finding is that e-cigarette use decreased over the course of the eight-week field trial. Due to the brevity of the trial reported in this thesis (Tucker, Bullen, et al., 2017b) it is unclear whether e-cigarette use would have ceased entirely over time, or stabilised at a lower level. The reductions in use may be attributed to changes in novelty or subjective effects (Kong, Morean, Cavallo, Camenga, & Krishnan-Sarin, 2015), or factors related to the methodology such as the single flavour provided (Farsalinos et al., 2013) and the requirement that participants had to use all of the different nicotine levels over the eight- week trial period. Having more independence with regard to using preferred flavours and nicotine content may encourage higher or more stable use over time. Naturalistic prospective studies would clarify this, but these studies could not be conducted in New Zealand

specifically until nicotine-containing e-cigarettes are legalised. Nonetheless, additional strategies may be required to encourage ongoing use of e-cigarettes and prevent relapse to smoking or increased cigarette consumption.

Results in Chapter 6 showed that e-cigarettes with cartridges of all nicotine levels functioned as partial substitutes for regular cigarettes (Tucker, Bullen, et al., 2017a) suggesting that their availability could reduce cigarette smoking. However, combining e-

cigarettes with other tobacco control mechanisms is likely to lead to greater benefits. One example of this is using a price differential to encourage switching (Wilson et al., 2015). This strategy is supported by the study in this thesis which found a positive CPE, indicating that as regular cigarette price increased, e-cigarette use increased and regular cigarette use

decreased. Price differentials may be implemented in a number of ways. Wilson et al. (2015) suggest applying excise tax increases to regular cigarettes but taxing e-cigarettes only with routine Goods and Services Tax (GST). Chaloupka et al. (2015) suggest applying different levels of excise tax to each product based on their risk profiles to encourage switching from regular cigarettes to e-cigarettes but keeping the price high enough to discourage initiation in young people or non-smokers. Another alternative may be for the Government to subsidise e- cigarettes as a Nicotine Replacement Therapy (NRT) in the same way that nicotine patches and gum are often subsidised. This may be combined with additional education campaigns providing accurate information about the relative health risks (McNeill et al., 2015), on the optimal and safe use of e-cigarettes, and potentially encouraging relatively low nicotine levels for first-time users.

8.3.3.1. E-cigarettes and tobacco control in New Zealand. As stated previously, price policy alone is unlikely to achieve the rapid reductions required to achieve the Smokefree 2025 goal in New Zealand, particularly for Māori/Pacific smokers. E-cigarettes have been proposed to be an attractive option for New Zealand smokers’ (Fraser, Chee, & Laugesen, 2016; Glover & McRobbie, 2015; Guiney, Li, & Walton, 2015; Li et al., 2013) but their current legal status in New Zealand restricts access to e-cigarettes that deliver nicotine. The studies in this thesis find that nicotine may play a role in determining the subjective effects of e-cigarettes and their subsequent use, which supports the Ministry of Health (2017) proposal to regulate nicotine-containing e-cigarettes as consumer products. This proposal would substantially increase access to e-cigarettes as an alternative product, especially for

lower-income smokers or those without credit cards in order to purchase nicotine-containing e-liquid online. This may have particularly significant implications for Māori/Pacific

smokers, who were found to be more price sensitive and also rated e-cigarettes more favourably than New Zealand European smokers (Tucker, Kivell, et al., 2017). As

demonstrated in Chapters 6 and 7, more favourable subjective effects ratings may increase demand for e-cigarettes and ongoing use (Tucker, Bullen, et al., 2017a, 2017b). However the study in Chapter 4 only used a simple, single-item measure of satisfaction and did not

specifically model the relationship between subjective effects and demand for Māori/Pacific smokers. Further research with a representative sample would be needed to examine the subjective effects of e-cigarette use in more detail and to test the predictive model in this population.

Making e-cigarettes available at a lower price than regular cigarettes may be particularly effective at reducing demand for regular cigarettes and encouraging use of e- cigarettes. This combination could be particularly effective for Māori/Pacific males, who were found to be more price sensitive than Māori/Pacific females. Due to lower levels of nicotine dependence and higher importance of social, cultural and behavioural cues for Māori/Pacific females (Tucker, Kivell, et al., 2017), nicotine in e-cigarettes may not be the most important factor. This may raise the question of why non-nicotine e-cigarettes have not been successful in reducing smoking prevalence for Māori/Pacific females thus far. It may be that social and environmental change would be required before e-cigarettes became an attractive alternative for Māori/Pacific females. Educational campaigns targeted at

Māori/Pacific females, and encouraging switching to e-cigarettes for Māori/Pacific males using price mechanisms, may help change the social interactions, cues and determinants of smoking and e-cigarette use for this population.

8.3.4. Implications for a comprehensive nicotine and tobacco control policy.