The use of e-cigarettes is often permitted in otherwise smoke-free areas causing passive vape exposure for present individuals. Little is known about the potential adverse health effects of passive vape, and people with respiratory diseases may be more susceptible.

The aim of the present study was to investigate local and systemic effects of short-term passive exposure to vape from e-cigarettes among patients with mild or moderate chronic obstructive pulmonary disease COPD in a randomized controlled double-blinded cross-over study.

Introduction: The use of e-cigarettes is often permitted in otherwise smoke-free areas causing passive vape exposure for present individuals. Little is known about the potential adverse health effects of passive vape, and people with respiratory diseases may be more susceptible.

Aim: to investigate local and systemic effects of short-term passive exposure to vape from e-cigarettes among patients with mild or moderate chronic obstructive pulmonary disease (COPD).

Design: In a randomised double-blinded cross-over study non-smoking COPD patients were exposed for four hours at two different exposure conditions separated by 14 days; A) clean filtered air and B) passive vaping under controlled environmental conditions.

Measurements: TSI P-TRAK Ultrafine Particle Counter was used for particle counts. Health effects, including lung function (FEV1/FVC) and fraction of exhaled nitric oxide (FeNO) were evaluated in relation to local and systemic effects prior to, right after and 24 h. after exposure.

Analysis: Mixed methods approach taking both time and exposure into account.

Inclusion Criteria:

• Never smoker or ex-smokers ≥ 6 months
• Aged 18+
• A known diagnosis of COPD (FEV1/FVC < lower limit of normal, app. 70%)
• MRC ≥ 2 or CAT score ≥ 10

Exclusion Criteria:

• Exposure to smoking more than 30 min./day
• Treatment with inhaled or oral corticosteroids
• Known hypersensitivity to constituents in e-cigarettes
• Any other disease that could influence the study parameters
• Conditions that prevent safe access to the climate chambers (such as claustrophobia)
• Perennial rhinitis
• Deformed nasal airways
• Not being able to change from long-acting medication to short-acting medication

Vaping was done in another chamber and thereby led into the exposure chamber, so it could not be observed. On days with clean air, vapers were chewing nicotine gum instead of vaping.