Alcohol-related injuries: Evidence for the prevention paradox

PURPOSE The risk of an injury increases exponentially with alcohol consumption on a given occasion, but the conclusion that alcohol-related injuries are attributable primarily to heavy drinking may or may not be correct. The prevention paradox states that a large number of people at small risk may contribute more cases of a particular condition than a smaller number of people who are individually at greater risk. We sought to determine the extent to which the prevention paradox applies in the relationship between alcohol consumption and injury. METHODS We conducted a population-based case-control and case-crossover study in all 3 emergency departments in Boone County, Mo. Data were collected from 2,517 patients with an acute injury and 1,856 age- and sex-matched controls selected by random digit dialing. RESULTS The population attributable fraction (PAF) associated with drinking in the 6 hours before injury-the proportion of injuries that would not have occurred in the absence of drinking-was 10.6% in case-crossover analysis and 8.5% in case-control analysis. The PAF that was due to what is usually considered nonhazardous alcohol consumption (fewer than 5 drinks for men, fewer than 4 for women) was 4.5% in case-crossover analysis and 3.1% in case-control analysis. The PAF that was due to alcohol dependence was 4.0%. CONCLUSIONS Injury is associated more with an occasion of alcohol consumption than with alcohol dependence. A substantial proportion of the PAF that is due to an occasion of alcohol consumption is from what are usually considered low-risk quantities.