Use of e-cigarettes and smoked tobacco in youth aged 14-15 years in New Zealand: findings from repeated cross-sectional studies (2014-19).

BACKGROUND: Media reports of a vaping epidemic among youth have raised concerns about the creation of a new generation of nicotine-dependent individuals who could graduate to cigarette smoking. We investigated the use of e-cigarettes and cigarettes in the youth of New Zealand from 2014 to 2019, with focus on daily use of these products as an indicator of potential dependence.
METHODS: We analysed data from the Action for Smokefree 2025 Year-10 survey, an annual cross-sectional survey of tobacco use undertaken by almost half of all school students aged 14-15 years (21 504-31 021 students). The survey includes questions on whether students had ever smoked (even just a few puffs) and their current smoking behaviour (at least once a day, week, or month, or less often than once a month). In 2014, a question was added asking if students had ever tried an e-cigarette. Subsequent surveys asked about e-cigarette use at least once a day, week, or month, or less often than once a month. We compared the frequency of e-cigarette use with cigarette smoking by survey year, age, gender, ethnicity, and school decile (a proxy for socioeconomic status). We did χ2 analyses to compare categorical variables and Cochran-Armitage trend tests to assess changes over time. Multiple logistic regression was used to determine predictors of e-cigarette and cigarette use in 2019.
FINDINGS: All measures of e-cigarette use increased and all measures of cigarette use decreased or remained static over time. Although the proportion of students who had ever tried e-cigarettes in 2019 (37·3%, 10 093 of 27 083), exceeded the proportion who had ever smoked (19·6%, 5375 of 27 354), daily use of products was low: e-cigarettes (3·1%, 832 of 26 532), cigarettes (2·1%, 575 of 27 212), both (0·6%, 159 of 27 633). In 2019, daily use of e-cigarettes was very low in never-smokers (0·8%, 175 of 21 385). Students who were Māori, Pacific, gender diverse, or from low-decile and mid-decile schools were more likely to be daily users of e-cigarettes or cigarettes, and males were more likely to be daily e-cigarette users, but less likely to smoke daily than females.
INTERPRETATION: The overall decline in smoking over the past 6 years in New Zealand youth suggests that e-cigarettes might be displacing smoking. Ongoing monitoring will be important to determine whether the liberalisation of e-cigarette availability and marketing in New Zealand has any effect on long-term patterns of daily e-cigarette and cigarette use. FUNDING: New Zealand Ministry of Health.