Associations between vaping and self-reported respiratory symptoms in young people in Canada, England and the US.

Background: Prevalence of youth nicotine vaping has increased, heightening concerns around negative health effects. This study aimed to compare self-reported respiratory symptoms among youth by vaping behaviours.

Methods: Participants (n = 39,214) aged 16-19 from the 2020 and 2021 International Tobacco Control Policy Evaluation Project (ITC) Youth Tobacco and Vaping Surveys (Canada, England, US). Weighted multivariable logistic regression assessed associations between reporting any of five respiratory symptoms in the past week (shortness of breath, wheezing, chest pain, phlegm, cough) and: past 30-day smoking and/or vaping; lifetime/current vaping. Among past-30-day vapers (n = 4644), we assessed associations between symptoms and vaping frequency, use of nicotine salts, usual flavour and device type(s).

Results: Overall, 27.8% reported experiencing any of the five respiratory symptoms. Compared with youth who had only vaped, those who had only smoked had similar odds of symptoms [adjusted odds ratio, OR (95% confidence interval, CI): 0.97 (0.85-1.10)], those who both smoked and vaped had higher odds [1.26 (1.12-1.42)], and those who had done neither, lower odds [0.67 (0.61-0.72)]. Compared with those who had never vaped, past use, experimentation and current regular or occasional use were all associated with higher odds. Reporting usually using nicotine salts was associated with higher odds of symptoms [1.43 (1.22-1.68)] than non-salt but was often uncertain. Compared with tobacco flavour (including with menthol), menthol/mint and sweets flavours were associated with similar odds; fruit [1.44 (1.07-1.93)], multiple [1.76 (1.30-2.39)] and 'other' [2.14 (1.45-3.16)] flavours with higher odds. All device types were associated with similar odds.

Conclusions: Among youth, vaping was associated with increased reporting of past-week respiratory symptoms. Among those who vaped, some flavour types and potentially nicotine salts were associated with respiratory symptoms.