Abstract
INTRODUCTION: The health implications of electronic cigarette (e-cigarette) use remain uncertain despite their increasing global prevalence. This study evaluates the health hazards of e-cigarettes on railway workers by comparing the differences in clinical and biochemical health indicators resulting from exposure to different smoking methods. METHODS: Using a retrospective cohort design, this study analyzed 7719 routine physical examinations and clinical health records from male railway workers in Shanghai (March 2022). Participants were stratified into four smoking subgroups: non-users, e-cigarette users, cigarette smokers, and dual users (concurrent e-cigarette and cigarette use). A multinomial logistic regression analysis evaluated the potential health impacts associated with each type of cigarette use, while a linear regression analyzed the impact of accumulated smoking years on these health indicators. RESULTS: E-cigarette use was associated with increased odds of elevated systolic blood pressure (AOR=1.12; 95% CI: 1.01-1.24; AOR=1.18; 95% CI: 1.06-1.31) and heart rate (AOR=1.18; 95% CI: 1.06-1.33) per 10-unit increase, as well as reduced urine pH (AOR=0.64; 95% CI: 0.52-0.80; AOR=0.70; 95% CI: 0.56-0.88) compared to non-users and cigarette smokers. Compared to cigarette use, e-cigarette use was associated with higher hemoglobin levels (AOR=1.22; 95% CI: 1.05-1.42) and increased aspartate aminotransferase levels for every 10-unit increment (AOR=1.23; 95% CI: 1.01-1.51). Furthermore, relative to non-users, e-cigarette users showed higher levels of white blood cells and carcinoembryonic antigen, with the largest effect sizes observed among e-cigarette users compared to other subgroups. In addition, the number of accumulated smoking years significantly impacted clinical and biochemical health indicators in both cigarette and e-cigarette users. CONCLUSIONS: E-cigarette use was associated with adverse alterations in several clinical and biochemical health indicators, some of which were comparable to or more pronounced than those observed in cigarette smokers. Public health policies are necessary to regulate their use, particularly in occupational settings.