E‐cigarette users are associated with asthma disease: A meta‐analysis

BACKGROUND: At present, there are more than 300 million asthma patients in the world. Electronic cigarettes (e-cigarettes) are considered as a new way of smoking and are loved by young people. The relationship between e-cigarettes and asthma risk is still controversial. Therefore, we conducted a meta-analysis to explore the relationship between e-cigarettes and asthma. METHODS: We searched PubMed, Embase, and Web of Science for research results published before august 2020. All data analysis was through R version 3.6.3. Publication bias was assessed using funnel plots, Begg's rank correlation test, and Egger regression asymmetry tests. Most of the included studies were adjusted for potential confounding factors. RESULTS: This meta found the association of e-cigarette use with asthma, and the combined OR value was 1.27 (95% CI = 1.17-1.37). We found the significant association of current e-cigarette usage with asthma (OR = 1.30, 95% CI = 1.17-1.45), and the former use of e-cigarettes also had an association with asthma (OR = 1.22, 95% CI = 1.08-1.39). Then, when e-cigarettes were used in combination with traditional cigarettes, the association odds with asthma was 1.47 (95% CI = 1.13-1.91), which was higher than that of users who used traditional cigarettes (OR = 1.33, 95% CI = 1.19-1.49). In subgroup analysis, adult and female e-cigarette users were more closely associated with asthma. CONCLUSION: In short, in this meta-analysis, we found that current or former use of e-cigarettes are associated with the prevalence of asthma. However, the specific relationship required more rigorous design for further verification.