Effects of various electronic nicotine delivery systems in asthma: a cohort study

BACKGROUND: Electronic nicotine delivery systems (ENDS) are becoming increasingly widely available and popular as an alternative to tobacco cigarettes; therefore, it is relevant to assess their effects on the disease course and symptom control in asthma. AIM: This study aimed to assess the effects of various ENDS on the course and control of asthma, pulmonary function, quality of life, and inflammation profile in patients aged 18–45 years. METHODS: An open-label observational study was conducted at City Clinical Hospital No. 24 (Moscow). Inclusion criteria: age 18–45 years; asthma for ≥12 months. Non-inclusion criteria: acute respiratory viral infection; pregnancy; chronic obstructive pulmonary disease or other lung diseases. Target parameters: asthma control (Asthma Control Test); quality of life (Asthma Quality of Life Questionnaire); forced expiratory volume in 1 second; inflammatory biomarkers (blood eosinophils, eosinophil cationic protein, periostin, thymic stromal lymphopoietin, interleukin 13). The assessments included validated questionnaires, spirometry, fractional exhaled nitric oxide test, and laboratory blood tests. RESULTS: The study included 153 patients (149 men and 4 women; mean age 22.14 ± 3.09 years). Of these, there were 59 nonsmokers and 94 smokers, with 56.4% using various ENDS. Smokers had a 2.7 point lower asthma control score on the Asthma Control Test (p 0.001), a 4.5% lower forced expiratory volume in 1 second (p 0.05), and a 0.83 point lower quality of life on the Asthma Quality of Life Questionnaire (p 0.001) than nonsmokers. In terms of inflammation profile, smokers had an 18.3% lower eosinophil cationic protein level (p 0.05), a 10.3% lower blood eosinophil count, and a 14.3% higher neutrophil count (p 0.01) than nonsmokers. Furthermore, smokers had a 31% higher periostin level (p 0.05) and a 73.5% higher thymic stromal lymphopoietin level (p 0.05). A subgroup analysis by the ENDS type revealed no significant differences (p 0.05). CONCLUSION: All ENDS had a comparable negative effect on asthma control, pulmonary function, and quality of life. Moreover, they altered the inflammation profile, with a decrease in eosinophils and an increase in neutrophils. Key limitations of this study are the cross-sectional design and the study sample primarily consisting of young males, preventing the extrapolation of findings to the overall population of patients with asthma.