Abstract Body (Do not enter title and authors here): Background: E-cigarettes may be less harmful than combustible cigarettes, though results from research with objective outcomes are limited. Comparisons of the cardiopulmonary effects of e-cigarettes and combustible cigarettes in controlled settings are necessary.
Aims: Examine cardiopulmonary effects of combustible cigarettes vs. e-cigarettes using a within-subjects design in individuals with chronic obstructive pulmonary disease (COPD) who smoke.
Hypothesis: Cardiopulmonary measures will improve following e-cigarette use compared to combustible cigarette use.
Methods: Twenty-one individuals ≥40 years old who smoke (≥5 cigarettes/day for ≥1 year) while diagnosed with COPD underwent two consecutive randomly ordered 2-week phases: a cigarette phase (usual-brand cigarettes) and nicotine-containing e-cigarette phase (combustible-cigarette abstinence with 3% and/or 5% nicotine tobacco-flavored JUUL available). During the e-cigarette phase, participants earned monetary incentives for CO readings ≤6ppm to promote cigarette abstinence. Pulmonary (spirometry, oscillometry, COPD Assessment Test [CAT], Saint George’s Respiratory Questionnaire for COPD [SGRQ-C]) and cardiac (heart rate, blood pressure) measures were completed at baseline and after each phase. Changes in pulmonary and cardiac measures across assessments were analyzed using a mixed-model repeated-measures ANOVA.
Results: Fourteen participants (66.66%) maintained cigarette abstinence during the e-ciguarette condition. There were no significant differences in objective (spirometry, oscillometry) or self-reported (CAT, SGRQ-C) by condition. Of the cardiac measures, diastolic blood pressure significantly differed by condition (F(2,40) = 3.87, p < 0.05), with higher measures after the completion of the cigarette phase (p = 0.02).
Conclusions: Participants were largely able to conform to the study conditions. However, cardiopulmonary changes were minimal with only diastolic blood pressure differing by condition. Nonetheless, the absence of impairments in pulmonary and cardiac health during this 2-week e-cigarette phase suggests evaluations of longer durations of e-cigarette exposure, with concurrent cigarette abstinence, are warranted to determine the safety of e-cigarettes as a potential replacement for combustible-cigarettes.