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

Abstract

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.

Electronic Cigarettes and Asthma: What Do We Know So Far?

“…Nonetheless, the study with the most participants supporting that was based on an online survey [ 99 ], thus there are serious concerns of a possible selection bias. These conclusions correspond with those of recently published systematic reviews with meta-analyses [ 93 , 100 , 101 ], and other comprehensive studies [ 123 , 124 ].…”

“…Studies suggesting that EC improves asthma control presented serious concerns about a possible selection bias, as they were based on online surveys data, or included a small number of asthmatics. Recently published systematic reviews with meta-analyses tally with the above conclusions [ 93 , 100 , 101 , 102 ]. More research is needed in order to study the effects of EC on lung function and airway inflammation of asthmatic patients.…”

“…Dual use, which is the most common usage pattern, is riskier than using either product alone [ 87 ]. Dual use, with even passive exposure to EC, was identified as significant predictor for asthma in two more cross-sectional studies [ 73 , 92 ] and one meta-analysis [ 93 ]. A recently published systematic review concluded that evidence up to now suggests that the side effects of ECs may be exaggerated in people with asthma [ 32 ].…”

“…A systematic review with meta-analysis found that former smokers who transitioned to EC showed approximately 40% lower odds of respiratory outcomes, including asthma, compared to current exclusive smokers [ 100 ]. However, that meta-analysis included only six studies (five cross-sectional and only three reported respiratory outcomes), whereas three more recently published systematic reviews with meta-analyses which included more studies with a lower percentage of cross-sectional studies found a significant association between EC use and dual use with asthma [ 93 ], both diagnosis and exacerbations [ 101 ], and after controlling for cigarette smoking and other covariates [ 102 ]. Most of the studies that were included in those meta-analyses are also included in the present review ( Table 2 ).…”

“…In two more studies from Italy, 18 asthmatic smokers that managed to switch from tobacco cigarettes to EC reported substantial health gains; however, two of them (11.1%) relapsed to tobacco cigarette [ 54 , 55 ]. Two recent systematic reviews with meta-analyses exhibited that former smokers who changed to EC showed better respiratory outcomes, including asthma, compared to current exclusive smokers [ 100 , 101 ]; however, dual use was associated with the worst outcomes as far as asthma [ 93 , 101 ]. This is particularly concerning since dual use seems to be the most common form of EC use [ 61 ].…”