Aims: To determine the relative risk (RR) of non-fatal injury associated with alcohol consumption in a series of emergency departments (EDs), possible effect modifiers and the impact of contextual variables on differences across sites.
Design: The case-crossover method was used to obtain RR estimates of the effect of alcohol on non-fatal injuries. Meta-analysis was used to evaluate the consistency and magnitude of RR across sites, and the extent to which contextual variables explain differences in effect sizes.
Participants: Probability samples of 11,536 injured patients attending 28 EDs studies in 16 countries (1984-2002). The majority of the sample was male (65%) and > 30 years old (53%).
Measurements: Exposed cases where those that consumed alcohol 6 hours prior to the injury. Usual alcohol consumption served as the control period.
Findings: Drinking within 6 hours prior to the injury was reported by 21% of the sample. The estimated (random) pooled relative risk for patients who reported alcohol use within 6 hours prior to injury was 5.69 (95% confidence interval = 4.04-8.00), ranging from 1.05 in Canada to 35.00 in South Africa. Effect size was not homogeneous across studies, as societies with riskier consumption patterns had a higher relative risk for injury. Heavier drinkers also showed lower RR.
Conclusions: Acute alcohol was a risk factor for non-fatal injuries in most sites. Policy measures addressed to the general population are recommended, especially in societies with riskier consumption patterns.