Passive exposure of COPD patients to e-cigarette vape - a double-blinded exposure chamber study

Abstract

Background: The use of e-cigarettes continues to grow worldwide. The assumption that e-cigarettes are less harmful than cigarettes has not been properly researched. In particular, studies on passive vaping by sensitive subgroups of the population are virtually non-existent. The aim of the present study was to investigate whether patients with chronic obstructive pulmonary disease (COPD) experience adverse effects of short-term passive exposure to e-cigarette vape. Here we present the results of preliminary statistical analyses performed before decoding exposures. Methods: In a climate chamber, we performed a double-blinded cross-over study with exposures lasting 3h to passive vaping or clean air among subjects with moderately severe COPD. We studied pulmonary function, exhaled NO and 28 self-reported symptoms before, during and after the exposures. Results: Sixteen patients (6 female; 10 male) with a mean age of 68 years recruited from an outpatient clinic completed the study. At entry the mean FEV1 was 1.43 L (53% of predicted), FVC was 2.53 L (74% of predicted) with a FEV1/FVC ratio of 0.57. FEV1 improved during the exposures and none of the exposures affected lung function negatively. The only symptom reported to be augmented during one compared with the other exposure was “current strength of smell” (p=0.038). Conclusion: Based on the preliminary analysis it appears that at the exposure levels in the present study, pulmonary function in patients with COPD was not affected by passive vaping. The study also suggests that blinding of e-cigarette vape exposure is difficult to obtain due to the odor. It also suggests that the odor itself did not affect lung function.