BACKGROUND AND AIMS In March 2024, the UK government announced plans to introduce a Vaping Products Duty that will tax e-liquids based on their nicotine strength. This study examined trends in the nicotine strength of e-liquids used by adult vapers and differences in those currently used across relevant subgroups.

DESIGN Nationally-representative, cross-sectional household survey, July 2016 to January 2024.

SETTING Great Britain.

PARTICIPANTS 7981 adult vapers.

MEASUREMENTS Participants were asked whether the e-cigarette they mainly use contains nicotine (yes/no) and the e-liquid strength (no nicotine, >0-≤ 6, 7-11, 12-19 or ≥20 mg/ml). We also collected information on the main device type used (disposable/refillable/pod), age, gender, occupational social grade, history of ≥1 mental health conditions, smoking status and (among past-year smokers) level of cigarette addiction.

FINDINGS The proportion of vapers in England using high-strength (≥20 mg/ml) e-liquids increased from an average of 3.8% (95% confidence interval [CI] = 2.9-5.0) up to June 2021 to 32.5% (CI = 27.9-37.4) in January 2024 (the vast majority of whom [93.3% in January 2024] reported using exactly 20 mg/ml; the legal limit). This rise was most pronounced among those using disposable e-cigarettes, those aged 18-24 years and all smoking statuses (including never smokers) except long-term (≥1y) ex-smokers. Of those surveyed in 2022-2024 in Great Britain, overall, 89.5% (CI = 88.1-90.8) said they usually used e-cigarettes containing nicotine, 8.7% (CI = 7.5-10.0) used nicotine-free e-cigarettes, and 1.8% (CI = 1.2-2.4) were unsure. The proportion using ≥20 mg/ml was higher among those mainly using disposable (47.9%) compared with pod (16.3%) or refillable (11.5%) devices; never smokers (36.0%), current smokers (28.8%) or recent (<1y) ex-smokers (27.4%), compared with long-term ex-smokers (13.9%); and younger (16-24y; 44.2%) compared with older (≥25y; range 9.4-25.1%) age groups. There were no notable differences across other subgroups of interest.

CONCLUSIONS Use of high-strength nicotine e-liquids in England appears to have increased sharply in recent years. Most adult vapers in Great Britain appear to use e-cigarettes that contain nicotine but different subgroups use different strengths: nicotine strengths tend to be higher among those who mainly use disposable devices and those aged 16-24y, and lower among long-term ex-smokers.