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

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.

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.

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.

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.