Vaping behaviour of high-risk and typically developing adolescents: results from the Gauging Risk and Resilience in Teenagers (GRIT) Study

Vaping or e-cigarette use among adolescents is a growing public health problem in Aotearoa New Zealand. Results from the Youth19 survey showed that almost 40% of secondary school students (age 13–18 years) had ever vaped, with 7.6% being regular users (monthly or more).¹ More recent data from the 2024/2025 New Zealand Health Survey showed that 16% of adolescents (15–17 years) and 30% of young adults (18–24 years) regularly vaped, with 14% and 23% respectively vaping daily.² These combined data suggest clear upward population trends in youth vaping over the last 10 years.^1,2 The one exception to this general trend is a small decline in daily vaping among youth under age 18 years in 2024. This was further confirmed by the 2024 ASH Year 10 Snapshot Survey, which found that rates of regular vaping among 14–15-year-olds had decreased from 20% in 2021 to 14% in 2024.³

E-cigarettes and vape products were initially developed as a less harmful alternative to combustible tobacco products (e.g., cigarettes) in adults, that could be used to aid smoking cessation. However, youth-targeted marketing and ease of availability of vape products corresponded with increases in vaping by young people, most of whom had never smoked before.^1,3 Moreover, youth smoking was declining rapidly before the introduction of vape products in New Zealand.³ As such, the introduction of higher nicotine concentrations in vaping products and the potential for nicotine addiction among previously non-smoking young people has been of concern.

Thus, to reduce the appeal of vaping and prevent vape use uptake in non-smoking youth, the New Zealand government has progressively amended its vaping legislation.⁴ Recent vaping regulations since mid-2023 include banning the use of cartoons and food imagery on vaping devices and packaging, using generic flavour descriptions and limiting nicotine concentrations in vaping products. Selling these products to young people under age 18 remains illegal. Despite these regulations, a recent study found that specialist vape retailers had poor age verification practices, and many did not comply with current regulations by selling disposable vape devices with high nicotine concentrations at discounted prices.⁵ The Smokefree Environments and Regulated Products Amendment Bill (No 2) was passed in December 2024.⁶ This now prohibits the sale of disposable vapes, bans visible displays of vape products in general stores and online and enforces strict advertising bans and higher penalties for breaches of the law. Further proximity restrictions have been added, and all new specialist vape retailers must now be located at least 300m from schools and marae and more than 100m from early childhood centres.

In addition to curtailing youth appeal and access to vape products, efforts must now be made to assist those young people who are already regular vapers and addicted to nicotine, to reduce or quit vaping and lessen long-term harms. This is particularly urgent given growing evidence of social inequities in vaping, with higher rates of use and addiction among Māori, Pacific and lower socio-economic youth,^2,3 and increased concentrations of specialist vape retailers in the most deprived neighbourhoods.⁷ Importantly, the harms associated with vaping, including physical and mental health risks,^8–11 are unlikely to be experienced equally, with high-risk youth—that is, those already experiencing significant health, social or economic disadvantage—more likely to be disproportionately affected.^3,12

Yet, little is known about vaping behaviour among these high-risk youth in New Zealand. Therefore, the primary objective of this study was to describe rates of vaping in a high-risk group of 16–19-year-old adolescents who were born to mothers with a substance use disorder and, in most cases, raised in adverse socio-economic and psychosocial family circumstances. We aimed to compare the extent and nature of vaping in this high-risk group with a regionally representative group of their same-age peers. We also aimed to examine vaping rates by sex, age, family socio-economic status (SES) and ethnicity.

Methods

Sample

This study reports cross-sectional data from a late adolescent follow-up of a prospective longitudinal study: Gauging Risk and Resilience in Teenagers (GRIT). The GRIT Study sample comprised two groups of adolescents aged 16 to 19 years, who were born between 2003 and 2008 at Christchurch Women’s Hospital in the Canterbury region of New Zealand. Exclusion criteria across both groups included very preterm birth (≤32 weeks), congenital abnormality, HIV diagnosis, suspected foetal alcohol syndrome, intent to deliver outside the Canterbury region and non-English speaking parents. A detailed description of the study cohort recruitment procedure is provided in an earlier paper.¹³ Characteristics of the sample are shown in Table 1.

High-risk group

The first group included 100 high-risk young people who were born to mothers who were prescribed methadone as part of their Opioid Substitution Treatment (OST) during pregnancy. All pregnant mothers who were in OST during the recruitment period were approached to take part, and 83% were successfully recruited. The median third-trimester methadone dose for participating mothers was 65.0mg/day (12.5–195.0mg/day). Excluding infant (n=4) and adolescent (n=2) deaths, 56% of the original sample was retained at the adolescent follow-up. There were no differences in individual or social background variables between those participants seen and those lost to follow-up, suggesting the retained sample remained broadly representative of children born to mothers with an opioid use disorder in Canterbury during that period.

Comparison group

The second group consisted of 110 non–opioid-exposed comparison children whose mothers were randomly selected from the delivery schedule of Christchurch Women’s Hospital, based on the expected due dates of children in the high-risk group (65% recruitment rate). A comparison of the socio-economic profile of this group of families with regional census data showed that they were generally representative of the Canterbury region during the recruitment period. Retention to late adolescence was 78%, excluding three children who were excluded due to severe neurodevelopmental impairment. Participants lost to follow-up were significantly more likely to have been born to mothers who smoked during pregnancy (p=.001), consumed any alcohol during pregnancy (p=.012) and whose mother had low educational attainment at the time of birth (p<.001).

View Table 1–4, Figure 1–5.

Procedures

All study procedures and measures were approved by the Southern Health and Disability Ethics Committee (ref: 2021 FULL 11202). Between the ages of 16 and 19 years, study participants were contacted via their parents/caregivers and invited to participate in an adolescent phase of the GRIT Study. In six instances in the high-risk group, parents did not grant the research team permission to contact the young person. Written informed consent was obtained from all participants. Each of these young people completed a comprehensive semi-structured interview administered by trained postgraduate students or research staff about their lifetime and current drug use, including vaping. These were predominantly in-person face-to-face interviews at the University of Canterbury’s Pukemanu Centre. However, where more convenient, some interviews were conducted in participant’s homes, over the phone or online via REDCap surveys. Interviewers were blinded to the participants’ study group wherever possible.

Measures

Vaping

Participants were asked about their lifetime and current vaping as part of their GRIT Study interview. Participants who responded yes to “Have you ever vaped?” were then asked a series of questions, including the age they first tried vaping, how frequently they currently vaped, extent of cigarette use prior to vaping and nicotine strength of vape products commonly used. In addition, those who reported vaping regularly (more than monthly) were asked a series of custom-written questions based on DSM-IV¹⁴ and DSM-5¹⁵ symptom criteria for nicotine dependence and adapted for vapers. For the present analyses, we report the total number of symptoms of nicotine dependence, as well as the proportion of adolescents reporting two or more dependence symptoms.

Individual and social background variables

Age was examined as a continuous variable. Sex was based on sex at birth. To examine vaping by ethnicity, participants reported all ethnicities they identified with (as reported in Table 1) and were then assigned a single ethnicity using the Ministry of Health – Manatū Hauora ethnicity prioritisation protocol.¹⁶ Family SES was assigned based on parents’/caregivers’ occupations at age 9.5 years. The highest-ranked occupation per household was used, with high, medium and low SES codes assigned using ANZSCO classifications¹⁷ and the Elley-Irving scale¹⁸. High SES included professional and managerial roles, medium SES included technical and skilled jobs, and low SES included semi/unskilled jobs and unemployment.

Statistical analysis

Descriptive statistics were used to determine vaping rates and vape product nicotine concentrations for the total sample. Vaping rates by study group and by individual and social background variables were then analysed using Chi-squared tests of independence and t-Tests for independent means. Logistic regression was used to examine independent associations between SES and vaping and Māori ethnicity (yes/no) and vaping.

Results

Self-reported youth vaping behaviour

Vaping data were available for 52 of the 53 high-risk participants (one incomplete interview) and all 83 comparison participants. Overall, vaping rates were high across both adolescent groups, with two-thirds of all adolescents having ever tried vaping and 43% reporting they were current regular (more than monthly) vapers. However, as shown in Table 2, adolescents in the high-risk group were 1.6 times more likely to report ever vaping (87% vs 55%, p<.001) and were more than twice as likely to regularly vape compared to control peers (64% vs 30%, p<.001). A tendency was also observed for the high-risk group to be more likely to convert from ever to regular vaping, but this did not reach statistical significance (73% vs 54%, p=.06). Further, a linear-by-linear association test indicated a significant trend toward more frequent use among those who had ever vaped in the high-risk group, χ²(1, N=91)=4.55, p=.033. The median age (15 years) of vaping onset was the same in both groups.

We also examined rates of combustible cigarette smoking among the young people who reported regular vaping (Table 2). Findings showed that vaping was not commonly used for smoking cessation. While a large proportion (particularly within the high-risk group) reported ever smoking (84% vs 60%), less than a quarter of regular vapers had tried smoking before they started vaping, and less than a quarter smoked regularly (at least monthly). Two young people in the high-risk group reported smoking daily, and both were regular vapers.

Vaping by sex

There were no sex differences in rates of ever vaping or regular vaping in the total sample, or within the high-risk group alone.

Vaping by age

As shown in Figure 1, there was a tendency towards higher rates of regular vaping with increasing age in the total sample (linear-by-linear association, p=.14). This association was not observed in the high-risk group alone, where similar proportions of the younger participants and older participants reported regular vaping (Figure 2).

Vaping by family SES

Figure 3 shows the proportion of regular vapers within each family SES band. There was a significant linear association between regular vaping and family SES (χ²[1, N=135]=5.56, p=.018) in the total sample, indicating that adolescents from lower-SES backgrounds were more likely to report regular vaping. This association was not observed within the high-risk group due to the limited variability in SES, as most participants in this group were from low-SES families. We therefore re-examined this association in the total sample, controlling for high-risk group status, with results showing that SES was not significantly associated with regular vaping (B=-0.008, SE=0.289-6, p=.98, OR=1.0 [0.6–1.7]).

Vaping by ethnicity

Rates of ever vaping were similar across all ethnic groups in the total sample. However, as shown in Table 3, a significant association was found between ethnicity and regular vaping in the total sample (χ²[3]=8.38, p=.039), with Māori youth over-represented among regular vapers (31%) compared to non-vapers (16.9%). The proportions of regular vapers within each ethnic group are shown in Figure 4.

We also examined rates of regular vaping across ethnic groups within the high-risk sample and found no association between Māori ethnicity and regular vaping. We therefore re-examined this association in the total sample accounting for family SES and found that Māori ethnicity was no longer significantly associated with regular vaping (B=0.57, SE=0.44, p=.19, OR=1.8 [0.8–4.1]).

Nicotine concentration

As shown in Figure 5, participants who were regular vapers most frequently reported using products containing 50–60mg/ml nicotine. Of the participants using these products, 87% were interviewed before the introduction of new labelling regulations mandating the reporting of freebase nicotine concentration, rather than the strength of nicotine salt, in vaping products. For those participants interviewed after these regulations were introduced, use of reusable vape pods and e-liquids containing 20–28.5mg/ml freebase nicotine, approximately equivalent in nicotine concentration to the 50mg/ml nicotine salt products, was common. Only a small proportion of regular vapers in the sample reported using lower-strength (≤15mg/ml) products.

Nicotine dependence

The proportions of regular vapers from each group who experienced symptoms of nicotine dependence are shown in Table 3. Common symptoms included having unsuccessfully tried to cut down or quit vaping (59% vs 54%, ns), being unable to go a day without vaping (52% vs 42%, ns) and having friends, family members or medical professionals concerned about their use or suggesting they cut down (46% vs 38%, ns). Adolescents in the high-risk group were 2.2 times more likely to report feeling tense or irritable if they needed to vape and couldn’t (67% vs 30%, p=.005), and 1.8 times more likely to want to vape first thing in the morning (61% vs 33%, p=.04). Further, adolescents in the high-risk group reported a significantly higher mean number of symptoms than comparison group adolescents (p=.03). Three-quarters, compared to less than half of the comparison adolescents (p=.02), reported two symptoms or more.

Discussion

This study provides valuable contemporary insights into current adolescent vaping in New Zealand, particularly among young people exposed to significant early life adversity, including prenatal substance exposure and family psychosocial risk. Vaping was widespread across the full sample of 16–19-year-olds, with two-thirds having tried vaping and 43% reporting regular (more than monthly) use. However, use was substantially higher among adolescents in the high-risk group, where almost 90% had tried vaping, and close to two-thirds were already regular vapers. Moreover, these youth were more likely to progress from experimentation to regular use and to vape more frequently than their peers. Notably, regular vaping in our high-risk cohort was around four times higher than national prevalence estimates,^1–3 underscoring the urgency of preventing and addressing vaping in vulnerable populations.

Consistent with prior research,¹ vaping was rarely used as a smoking cessation tool. More than three-quarters of regular vapers had never smoked cigarettes before trying vaping, thus raising serious concerns about new pathways to nicotine dependence for youth who might otherwise have never used tobacco. Alarmingly, most regular users reported using very high-nicotine devices, which deliver large doses of nicotine per puff. The rapid nicotine delivery, ease of concealment and the difficulty young people can face in monitoring or limiting their intake heighten the risk for dependence and longer-term health and neurodevelopmental harm.^9,12,19 Among regular vapers in the high-risk group, three-quarters reported two or more symptoms of nicotine dependence, including withdrawal, craving and difficulty quitting, indicating a clinically concerning level of addiction in this already vulnerable group.

While a trend toward age-related increases in regular vaping was observed in the total sample, this pattern was absent among the high-risk adolescents, who showed consistently high rates of use across age groups. This indicates that developmental stage alone did not account for increased vaping risk and suggests the need to consider the role of other prenatal and postnatal biopsychosocial experiences and exposures in placing these youth at increased risk of substance use. Such factors may include prenatal as well as childhood/adolescent exposure to parental nicotine and other substance use, and exposure to a range of adverse childhood experiences (e.g., child maltreatment, family violence, family instability, household mental illness, neighbourhood disadvantage), all of which can affect neurodevelopmental pathways related to self-regulation and reward sensitivity.^7,20–24 This highlights the importance of early identification and intervention efforts that address the broader developmental and environmental contexts of high-risk youth.

Similar mechanisms may help explain the higher rates of regular vaping among adolescents from low-SES backgrounds in the total sample. Although this association was attenuated after adjusting for high-risk group status, likely reflecting the substantial overlap between low SES and inclusion in the high-risk group, previous research indicates that socio-economic disadvantage independently contributes to elevated substance use risk.^25–27

Ethnic disparities were also evident, with Māori youth significantly over-represented among regular vapers, consistent with national findings.^2,3 However, this association was no longer significant after controlling for SES, suggesting that structural economic disadvantage may underlie much of the observed ethnic disparity. These findings highlight the need for culturally responsive and equity-focussed prevention and intervention strategies.

Public health implications

Although adolescent smoking has declined in New Zealand, the independent surge in vaping popularity among adolescents has disproportionately affected those already facing systemic disadvantage, including Māori, low-income, and high-risk youth. This has not only widened existing health inequities but also created new challenges for our public health system. There are existing gaps in cessation support for vulnerable youth, who are unlikely to access general practitioner support or to sign up for online plans and mobile helplines proactively. Enforcing current restrictions around marketing, product strength and retail access is vital, but not sufficient. Equity-focussed strategies also need to include the development of accessible, youth-friendly and culturally appropriate cessation pathways.

Strengths and limitations

This study draws on a prospectively followed cohort of high-risk adolescents, providing unique insight into vaping among youth exposed to early life adversity and family psychosocial risk. Blinded interviewers, detailed vaping and dependence measures, and robust measures of individual and social background variables strengthen the validity of the findings. Limitations include modest retention in the high-risk group (56%) and selective attrition in the comparison group, which may have led to underestimation of vaping rates and inflated group differences. The sample size was relatively small, limiting power to detect more subtle associations. Finally, data relied on self-reporting and were collected during a period of regulatory change, which may affect generalisability over time. Despite these limitations, the study provides important evidence of significant and inequitable patterns of vaping and likely nicotine dependence among New Zealand youth, with clear implications for public health responses.

Conclusion

Vaping is widespread among adolescents in Aotearoa New Zealand, but disproportionately affects high-risk youth already disadvantaged by social inequities. Targeted prevention, stronger regulation and culturally responsive cessation support tailored to the unique vulnerabilities of these young people are urgently needed to tackle this growing public health problem.