Chronic health effects associated with electronic cigarette use: a systematic review.

This document is a systematic review of studies examining the effects of e-cigarette use on health outcomes. a total of 180 studies were included in the review after removing duplicates and screening for relevance. Of these, 59 studies focused on daily e-cigarette users, and 20 studies focused on exclusive e-cigarette users (i.e., those with no history of cigarette smoking). The narrative synthesis of the findings in the review focused only on daily e-cigarette users, due to increased uncertainty in exposure levels for occasional users or when the duration of e-cigarette use was unclear.

The review used a modified Grading of Recommendations assessment, Development and Evaluation (GRaDE) approach to assess the overall certainty of evidence by outcome. The findings for 93 studies that reported on one or more of the 11 most common outcomes are summarized in the document.

The review found that certain biomarkers, such as neutrophil elastase, matrix metalloproteinase-2 (MMP-2), and matrix metalloproteinase-9 (MMP-9), were significantly higher among exclusive e-cigarette users (ECUs) than among non-smokers (NSs), while there was no difference in protease inhibitors (a1aT, SLPI, TIMP-1, and TIMP-2) between ECUs and NSs. In addition, the review found that IgE was significantly higher among ECUs than among NSs, but that IgG did not differ significantly between the two groups. These findings resulted in a 50/50 split in vote counting.

Overall, the review suggests that there are some negative health effects associated with e-cigarette use, particularly among daily users. however, more research is needed to fully understand the long-term health consequences of e-cigarette use.

Wasfi Ra, Bang F, de Groh M, et al. Chronic health effects associated with electronic cigarette use: a systematic review. Frontiers in public health. 2022;10:959622. doi:10.3389/fpubh.2022.959622