title: Factors associated with pre-drinking among nightclub patrons in the city of São Paulo.
abstract: OBJECTIVE
  The aim of the study was to describe the phenomenon of pre-drinking (alcohol consumption before entering nightclubs or bars) and to identify factors associated with pre-drinking practices among patrons in the city of São 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-drinking 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-drinking 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Preventive Medicine, Section of Epidemiology, Universidade Federal de Sao Paulo, Sao Paulo, Brazil.
authors.forename: Mariana G R
authors.initials: MG
authors.lastname: Santos
authors.affiliation: Department of Information in Health, Section of Statistics, Universidade Federal de São Paulo, Sao Paulo, Brazil.
authors.forename: Angela T
authors.initials: AT
authors.lastname: Paes
authors.affiliation: Department of Preventive Medicine, Section of Bioestatistics, Universidade Federal de Sao Paulo, Sao Paulo, Brazil.
authors.forename: Adriana
authors.initials: A
authors.lastname: Sanudo
authors.affiliation: Department of Preventive Medicine, Section of Epidemiology, Universidade Federal de Sao Paulo, Sao Paulo, Brazil zila.sanchez@unifesp.br.
authors.forename: Zila M
authors.initials: ZM
authors.lastname: Sanchez
mesh_terms: D000293:Adolescent; D000328:Adult; D000428:Alcohol Drinking / Q000453:epidemiology* / Q000523:psychology; D001938:Brazil / Q000453:epidemiology; D001944:Breath Tests; D003625:Data Collection; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D014505:Urban Population / Q000706:statistics & numerical data; D055815:Young Adult