Association of electronic cigarette use and risk of COPD: a systematic review and meta-analysis

Chronic Obstructive Pulmonary Disease (COPD) is a global health concern, primarily linked to cigarette smoking. The potential role of electronic cigarettes (e-cigarettes) in COPD development remains unclear. Despite growing popularity as a smoking alternative, evidence suggests e-cigarettes may have harmful respiratory effects. This systematic review and meta-analysis assess the relationship between e-cigarette use and odds of having COPD. A comprehensive search of Web of Science, Embase, and PubMed was conducted to identify observational studies that assessed the association between e-cigarette use and the risk of COPD, providing risk estimates (hazard ratios, risk ratios, or odds ratios) for current, former, and ever e-cigarette users. Random-effects meta-analysis was performed using R software (V 4.4), and heterogeneity was assessed with the I² statistic. Sensitivity analyses were conducted to test the robustness of the findings. Publication bias was evaluated using Egger's test and funnel plots. Seventeen studies (1087 records screened) were included. E-cigarette use was associated with significantly higher odds of COPD compared to non-use. The pooled odds ratios were 1.48 (95% CI: 1.36-1.61) for current users, 1.84 (95% CI: 1.51-2.23) for former users, and 1.79 (95% CI: 1.42-2.25) for ever users. Sensitivity analysis confirmed the robustness of the findings. E-cigarette use is associated with higher odds of having COPD. Public health efforts should consider raising awareness of the potential respiratory risks associated with e-cigarette use.