Blood Ethyl Alcohol Level, Clinical Outcomes and Number of Injured Body Regions in Young Adults after Traffic Accidents: A Retrospective Cohort Study

Aim: To evaluate the association of blood ethyl alcohol concentration (BAC) with clinical outcomes, the number of injured anatomical regions and laboratory parameters in emergency department patients aged 20-40 years after traffic accidents. Materials and Methods:This single-center retrospective cohort study included 451 patients whose BAC was measured between October 2022 and October 2023.BAC was categorized as 0, >0-50, or >50 mg/dL (legal limit).Group comparisons were assessed using the chi-square test, Fisher's exact test, the Mann-Whitney U test; correlations were assessed using Spearman's rho.Extremity involvement was analyzed with logistic regression adjusted for age and sex.All analyses were exploratory, with false discovery rate correction applied.Results: Measurable alcohol was detected in 131 patients (29.0%), and 79 patients (17.5%) were above the legal limit.Males predominated in the above-limit group (93.7% vs. 78.0%;p=0.002).No statistically significant associations were observed for mortality [1.3% vs. 2.2%; odds ratio (OR) 0.58, 95% confidence interval (CI) 0.07-4.73],hospital admission (OR 1.59, 95% CI 0.93-2.73),surgical intervention (OR 1.31, 95% CI 0.64-2.67),or extremity involvement (adjusted OR 1.71, 95% CI 0.99-2.97).BAC was correlated weakly with the number of injured regions (rho=0.204,95% CI 0.114-0.291),alanine aminotransferase (rho=0.297),and aspartate aminotransferase (rho=0.341)(all q<0.001).The number of injured regions increased across alcohol categories (Jonckheere-Terpstra p<0.001), driven mainly by differences between patients with and without measurable alcohol. Conclusion:In young adults following traffic accidents, BAC was not significantly associated with mortality, admission, surgery, or extremity involvement, although the statistical power to detect an association with mortality was limited.Measurable alcohol was weakly associated with a greater number of injured regions and higher liver enzyme levels.These exploratory findings require prospective confirmation with validated injury-severity scores.