The impact of e-cigarettes versus traditional cigarettes on long-term cardiopulmonary outcomes

Electronic cigarettes (e-cigarettes) have emerged as potential harm reduction tools for conventional smokers, with proponents claiming reduced health risks. However, comprehensive evidence regarding their long-term cardiopulmonary effects remains limited. This scoping review aims to systematically map and compare the cardiopulmonary effects of e-cigarettes versus traditional cigarettes through the synthesis of clinical and preclinical evidence, focusing on chronic exposure outcomes and biological mechanisms. Through systematic searches in MEDLINE (n = 1,398), EMBASE (n = 1,300), and Web of Science (n = 642), we identified 30 relevant studies from 3,791 unique records examining cardiopulmonary endpoints with chronic exposure measurements. Although e-cigarettes generally demonstrated reduced toxicity compared with traditional cigarettes, they induced significant cardiopulmonary alterations. Key findings included increased inflammatory responses, oxidative stress, endothelial dysfunction, and altered immune responses. Both products affected cardiovascular function and tissue remodeling, although e-cigarettes typically showed reduced severity. Notably, the base components of e-cigarettes, propylene glycol/vegetable glycerin, independently contributed to observed effects. Current evidence suggests e-cigarettes may offer harm reduction potential compared with traditional cigarettes but are not harmless with respect to cardiopulmonary health. Long-term clinical data remain limited, highlighting the need for continued research on their chronic health outcomes.