Environmental characteristics associated with alcohol intoxication in Brazilian nightclubs

INTRODUCTION: Few studies have investigated the association between environmental factors and patrons’ binge drinking in nightclubs. The few studies on this topic usually fail to control analysis to alcohol intoxication in the nightclub for patron's blood alcohol concentration before entering the nightclub. No previous study has investigated this issue in developing countries. The aim of this study is to identify environmental factors associated with binge drinking among patrons in nightclubs in São Paulo, Brazil, using a mixed method design. 

METHODS: The study used a two-stage cluster sampling survey design, sampling with probability proportional to the size of the nightclubs. Two levels of data were collected: ethnographic and portal survey. Individual-level data was collected by a portal survey in 2422 subjects at the entrance (acceptance rate of 80%), and 1822 at the exit of 31 nightclubs (same subjects in two time points data collection). Weighted multilevel analysis was used to investigate the association of patrons binge drinking (as measured by Breath Alcohol Concentration – BrAC>0.38mg/l) at the exit with environmental level variables – collected through ethnography and controlled for individual-level data. Ethnographic data was subjected to Content Analysis. This study was the first survey on nightclubs in Brazil and used an innovative qualitative-quantitative integrated design of data collection and analysis.

RESULTS: Pre-drinking (drinking alcoholic beverages before entering the nightclub) was the variable most strongly associated with binge drinking BrAC levels at the exit of the venue (aOR=5.98, 95%CI[4.37;8.17], p<0.001). The environmental variables significantly associated with binge drinking were: “all-you-can-drink-service” (aOR=2.44, 95%CI[1.03;5.79], p=0.043); two or more dancing floors (aOR=1.92, 95%CI[1.16;3.18], p=0.011) and higher sound levels (aOR=1.04 per each decibel increased, 95%CI[1.01;1.08], p=0.048). Triangulation of data analysis showed association between ketamine use in LGBT nightclubs and lower alcohol intoxication.

CONCLUSIONS: Pre-drinking showed that individual-level characteristics could be more important in binge drinking than environmental characteristics of the venues. Environmental control interventions, isolated from individual level approaches may have limited efficacy in the prevention of alcohol abuse in nightclubs.