Does alcohol cause injury: The bottle's fingerprints on the victims

Background: Although many injuries involve alcohol, no one has shown alcohol causes injuries except in road crashes. Instead, lifestyle may cause excess involvement. Using uninjured emergency department attendees as controls misestimates risk as illness may discourage drinking alcohol many hours before attendance.

Objectives: To determine whether (1) regular heavy drinkers have higher hospitalized injury risks than other people when alcohol-negative, (2) hospitalized injury risk of both regular heavy drinkers and other drinkers rises when they are alcohol-positive, (3) being alcohol-positive differentially raises hospitalized injury risk of heavy drinkers versus other drinkers.

Methods: By combining national survey data on alcohol consumption with estimated alcohol metabolism rates, we estimated the hours spent alcohol-positive versus alcohol-negative during a year for heavy alcohol drinkers versus other people. The analysis accounted for secondary metabolism channels developed by heavy drinkers. Hospitalized injury rates for these groups by alcohol involvement were estimated with data from published sources: statewide Oklahoma data on selected injuries, Baltimore trauma center data, and a national health care claims data set. Relative risks were computed algebraically, with extensive sensitivity analysis.

Results: Relative to other alcohol-negative people aged 18 and older, regular heavy drinkers have a relative injury risk of 1.4 when alcohol-negative (sensitivity range 1.0-3.3) and 4.3 when alcohol-positive (range 2.0-9.3). Others have a relative injury risk of 1.0 when alcohol-negative and 6.8 when alcohol-positive (range 3.8-12.1). Among people aged 18 and older, 27% of hospitalized injuries are alcohol-involved and 24% are alcohol attributable. At least 88% of assaults with alcohol-involved victims (36% of all hospitalized assaults) were attributable to alcohol use.

Conclusions/Impact: Alcohol causes injury. Regular heavy drinkers lead risky lifestyles. They tolerate alcohol better than most drinkers but still experience elevated injury risks when drinking. This method is transferable internationally. The results strengthen the case for public health intervention.