Factors Associated with Pre-drinking Among Nightclub Patrons in the City of São Paulo

Aims: The aim of the study was to describe the phenomenon of pre-drinking (alcohol consumption before entering night- clubs or bars) and to identify factors associated with pre-drinking practices among patrons in the city of Sao Paulo, Brazil. Methods: Individual-level data were collected by a portal survey of 2422 patrons at the entrance and at the exit of 31 nightclubs. The nightclubs were selected by two-stage sampling using a probability proportional to the establishments' capacity in the first stage and a systematic sample of patrons in the second stage. Breath alcohol concentration (BrAC) was measured. Face-to-face interview identified pre-drink- ing characteristics and past-year risk behaviors. Analysis used sample weights to compensate for nightclubs or patrons that were possibly over- or under-represented. Results: Of the study participants, 41.3% (95% confidence interval (CI) = 33.7-49.3) engaged in pre-drink- ing on the night of the interview. Being male (odds ratio (OR) = 1.98, 95% CI = 1.45-2.71), past-year binge drinking (OR = 2.28, 95% CI = 1.70-3.07), previous episodes of severe effects from drunkenness (OR = 1.77, 95% CI = 1.40-2.22) and sexual risk behavior (OR = 1.67, 95% CI = 1.20-2.33) were associated with recent pre-drinking. Pre-drinking predicted higher BrACs at the nightclub exit. Conclusion: Pre-drinking is prevalent among nightclub patrons and associated with risk behaviors, and is associated with alcohol intoxication at nightclub exits. Environmental prevention strategies must consider pre-drinking as a potential risk factor for alcohol intoxication in nightclubs. during nights out in an attempt to reduce alcohol intoxication, thereby decreasing violent episodes and other risk behaviors associated with alcohol. Accordingly, the present study aimed to describe the phenomenon of pre-drinking and to identify factors associated with pre-drinking among nightclub patrons in the city of Sao Paulo. The main hypothesis was that drink- ing prior to entering a nightclub does not lead to lower alcohol consumption in nightclubs but to higher BrAC levels at night- club exits.