The relationship between alcohol consumption and fatal motor vehicle injury: high risk at low alcohol levels.

BACKGROUND

Alcohol consumption causes motor vehicle accident (MVA) injury in a dose-response fashion. However, the relationship between how this risk is different with respect to fatal and nonfatal outcomes is not clear. A meta-analysis has already been completed for alcohol consumption and nonfatal MVA injury, but none exists for fatal injury. Thus, an analysis of the acute dose-response relationship between alcohol and motor vehicle injury death is warranted to generate single occasion- and dose-specific relative risks for the first time.

METHODS

A systematic literature review and inverse-variance weighted, random effects meta-analysis were conducted to fill this gap. Fractional polynomial regression was used to model the dose-response relationship. Usual tests of heterogeneity and publication bias were run.

RESULTS

Five studies meeting the inclusion criteria of this analysis were selected. At all levels of blood alcohol concentration (BAC), the odds ratio (OR) of fatal motor vehicle injury was significant. Overall, the 5 combined studies yielded an OR of fatal injury of 1.74 (95% CI: 1.43-2.14) for every 0.02% increase in BAC. At 0.08, the legal limit in most countries, the OR was 13.0 (95% CI: 11.1-15.2).

CONCLUSIONS

This study is able to definitively show and quantify, for the first time, the significantly increased OR for fatal motor vehicle injury. This analysis showed some evidence of both study heterogeneity and publication bias, likely due to the increased variation we could expect from a small study number. The alcohol-caused fatal motor vehicle injury literature is sparse with respect to dose-response information. More studies investigating this relationship and other injury types are recommended in this area to be able to calculate stable estimates of risk overall and by injury type specifically.