Risk of Past Year Injury Related to Hours of Exposure to an Elevated Blood Alcohol Concentration and Average Monthly Alcohol Volume: Data from 4 National Alcohol Surveys (2000 to 2015).

BACKGROUND: While a strong association exists between alcohol and injury in emergency department (ED) studies, these studies are not representative of the general population.

METHODS: The association of injury with the number of hours of exposure to a blood alcohol concentration (BAC) ≥ 0.05 and average monthly volume in drinks, both based on self-report of quantity and frequency of drinking in the last year, in a merged sample of respondents (n = 29,571) from 4 U.S. National Alcohol Surveys (2000 to 2015) are analyzed. Risk curves based on categorical step function and fractional polynomial modeling were analyzed separately by gender, and by age and race/ethnicity for males.

RESULTS: Risk of injury increased at 1 hour of a BAC exposure of ≥ 0.05 and at an average monthly volume of 1 drink. Risk of injury for spirits increased to an average daily volume of 1 drink, but no association was found for injury risk and average volume for either wine or beer. Risk of injury increased with both exposure hours and monthly volume among males, but little association was found for either consumption measure with risk of injury for females. Among males, increased risk of injury was greater for whites than for blacks or Hispanics for BAC exposure; Hispanics showed a continued elevated risk up to 8 hours of exposure. After peaking at a monthly volume of 1 drink, injury risk decreased substantially for blacks, but was more gradual for whites, while risk increased very slightly for Hispanics to about 4 drinks per day. Males aged 18 to 29 showed the largest increase in risk associated with the number of hours of exposure to a BAC of ≥0.05, with risk doubling at 1 hour of exposure, but subsequently falling.

CONCLUSIONS: While findings here are weaker than those from ED studies and likely due to the context of drinking, risk of injury appears to increase at relatively low levels of consumption, suggesting the importance of preventive efforts to reduce injury not only for heavier drinkers but also for more moderate drinkers.