Perceived Harm of Vaping Relative to Smoking and Associations With Subsequent Smoking and Vaping Behaviors Among Young Adults: Evidence From a UK Cohort Study.

Introduction: There is a lack of evidence on whether vaping harm perceptions can predict vaping and smoking behaviors among young adults in the United Kingdom. We aimed to assess whether the perceived harm of vaping relative to smoking is associated with subsequent changes in vaping and smoking behaviors in this population.

Methods: Data were from the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective cohort study. Longitudinal associations were assessed between the perceived harm of vaping relative to smoking at baseline (approximately 24 years old; Nov'15-Aug'17) and the following smoking/vaping outcomes at follow-up (approximately 30 years old; May-Oct'22): (1) stopping smoking, (2) initiation of ever smoking and/or vaping, and (3) uptake of past 30-day smoking and/or vaping. Multinomial logistic regressions were used, adjusting for sociodemographic factors.

Results: Among young adults who smoked but did not vape at baseline (n = 687), the perception that vaping is less harmful than smoking (vs. equally/more harmful, or don't know) was associated with stopping smoking and now vaping at follow-up (adjusted Relative Risk Ratio (aRRR)=1.69, 95%CI = 1.02 to 2.81, p = .04). Initiation of ever smoking/vaping, or uptake of past 30-day smoking/vaping, were not common during the study period and there was little evidence that these outcomes were associated with relative vaping harm perceptions at baseline.

Conclusions: Among young adults who smoke, perceiving vaping as less harmful than smoking was associated with switching from smoking to vaping six years later. Few young adults who did not smoke or vape initiated these behaviors during the study period.

Implications: This is the first study in England to find that young adults who smoked and who accurately perceived vaping as less harmful than smoking were more likely to switch to vaping 6 years later. This is consistent with prior studies among adults and highlights the need for interventions to improve the pervasive misperceptions about vaping that are currently observed among young adults who smoke.