Predictors of positive Blood Alcohol Concentration (BAC) in a sample of Brazilian drivers

To verify the frequency of positive Blood Alcohol Concentration (BAC) among drivers and to examine associated factors in a cross-sectional study of Brazilian state capitals.

3,398 drivers were approached on highways crossing all 27 Brazilian capitals from 12 p.m. to 12 a.m. (Fridays and Saturdays). They were breathalyzed and data on their driving characteristics and alcohol consumption were collected. Multivariate logistic regression following a hierarchical conceptual framework was used to evaluate associated factors.

The overall weighted prevalence of positive BAC (> 0.1 mg/L) was 4.2%. The multivariate analysis showed that education up to 8 years (OR = 2.0; 95% CI: 1.4-3.0), age > 30 years (OR = 2.6; 95% CI: 1.8-3.8), type of vehicle (cars: OR = 3.0; 95% CI: 1.7-5.1; motorcycles: OR = 3.7; 95% CI: 2.1-6.4), binge drinking (OR = 1.7; 95% CI: 1.3-2.4), having been breathalyzed before (OR = 2.6; 95% CI: 1.8-3.7), and purpose of the trip (coming from a party: OR = 1.9; 95% CI: 1.3-3.0; leisure trip: OR = 1.7; 95% CI: 1.32.4; driving after 8 p.m.: OR = 1.7; 95% CI: 1.3-2.3) were independently associated with DUI.

Study findings suggest that selected external environmental factors, such as socioeconomic and demographic characteristics as well as personal characteristics like alcohol consumption and the relationship between drinking and driving were associated with positive BAC among Brazilian drivers. Results can help to inform drinking and driving policy and preventive approaches.