DOES VAPING IMPAIR LUNG FUNCTION IN YOUNG ADULTS?

<bold>Background:</bold> It remains unclear whether the use of electronic cigarettes (e-cigarettes or vaping) impairs lung function. We aimed to compare measures of lung function (spirometry and multiple breath washout) between young adults who vape and age-matched healthy controls. <bold>Methods:</bold> Healthy participants (18-24 years) without a history of respiratory disease, and age-matched participants who self-reported regular e-cigarette use were recruited. Participants were classified into four exposure groups: no exposure, low (1-2 puffs/hour), moderate (3-4 puffs/hour) and heavy (5+ puffs/hour). The primary outcomes were % predicted FEV1 and lung clearance index (LCI), measured using the Exhalyzer D™. <bold>Results:</bold> A total 56 participants had paired FEV1 and LCI measurements (24 no exposure, 6 low, 6 moderate, 20 heavy). The vaping group, on average, had 1-5 years of exposure. FEV1 % predicted was similar between the healthy and vaping group (mean difference:0.9% (95%CI -7.78;5.92); whereas ventilation inhomogeneity (LCI) was worse in the vaping group (mean difference 0.27 (95%CI 0.08;0.46)). A dose response was observed across exposure levels for LCI (Figure); the highest exposure group had a 0.4 unit (95%CI 0.1;0.56) higher LCI than the healthy controls. <bold>Conclusion:</bold> There is a small measurable effect of vaping exposure on ventilation inhomogeneity, suggesting that even in otherwise healthy young adults, vaping begins to cause harmful functional changes in the small airways. <fig><object-id>erj;64/suppl_68/OA2880/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>