Person and environment predictors of blood alcohol concentrations: a multi-level study of college parties.

AIMS This study builds upon previous research by assessing the relationship of breath blood alcohol concentrations (BrAC) to environmental and individual characteristics. DESIGN We conducted a multi-level study of college parties. Our design included observational measures of party environments, a brief self-administered questionnaire, and the collection of breath samples from partygoers. SETTING Data were collected in private residences of students living in a neighborhood adjacent to a large public university located in the Southwestern United States. PARTICIPANTS A total of 1,304 individuals attending 66 parties participated in the study. MEASURES Observational measures of party characteristics were made by 2 trained research assistants at each party. Four to 5 trained interviewers administered a brief field survey to partygoers at each party. In addition, the trained interviewers collected breath samples using handheld breathalyzer devices. FINDINGS Hierarchical linear modeling analyses revealed significant variation at the party and individual levels. At the individual level, motivations to socialize were significantly associated with lower BrAC, while drinking games and providing the sample after 11:00 pm were associated with higher BrACs. At the party level, large parties were significantly associated with lower BrACs while reports of many intoxicated partygoers were associated with higher BrACs. Finally, we identified a significant gender by theme party interaction, indicating women had higher BrACs at theme parties relative to nontheme parties; however, BrACs for men were similar regardless of the type of party attended. CONCLUSIONS Alcohol consumption among young adults in natural settings is a function of both person and environmental factors.