The effect of lowering the legal blood alcohol concentration limit on driving under the influence (DUI) in southern Taiwan: a cross-sectional retrospective analysis

Abstract

ObjectivesWe aimed to profile the epidemiological changes of driving under the influence (DUI) in southern Taiwan after the legal blood alcohol concentration (BAC) limit was lowered from 50 to 30 mg/dL in 2013.SettingLevel 1 trauma medical centre in southern Taiwan.ParticipantsData from 7447 patients (4375 males and 3072 females) were retrieved from the trauma registry system of a single trauma centre to examine patient characteristics (gender, age and BAC), clinical outcome variables (Abbreviated Injury Score, Injury Severity Score and mortality) and vehicular crash-related factors (vehicle type, airbag use in car crashes, helmet use in motorcycle crashes and time of crash) before and after the BAC limit change.ResultsOur results indicated that the percentage of DUI patients significantly declined from 10.99% (n=373) to 6.64% (n=269) after the BAC limit was lowered. Airbag use in car crashes (OR: 0.30, 95% CI 0.10 to 0.88, p=0.007) and helmet use in motorcycle crashes (OR: 0.20, 95% CI 0.15 to 0.26, p<0.001) was lower in DUI patients compared with non-DUI patients after the BAC limit change, with significant negative correlation. DUI behaviour increased crash mortality risk before the BAC limit change (OR: 4.33, 95% CI 2.20 to 8.54), and even more so after (OR: 5.60, 95% CI 3.16 to 9.93). The difference in ORs for mortality before and after the change in the BAC legal limit was not significant (p=0.568).ConclusionThis study revealed that lowering the BAC limit to 30 mg/dL significantly reduced the number of DUI events, but failed to result in a significant reduction in mortality in these trauma patients.