Injury Alcohol-Attributable Fractions: Methodological Issues and Developments

Background: Alcohol-attributable fractions (AAFs) are routinely used to estimate the burden of injury resulting from alcohol. Recent methodological advances allow AAFs to be estimated using national survey data. However, this requires assuming that the drinking patterns are equivalent to those used by epidemiological studies estimating the relative risk of injury. This study explores the implications of this assumption and presents an improved method of estimating injury AAFs. Methods: Diary survey is used to describe individuals’ drinking occasions and estimate AAFs. Statistical methods and numerical integration are used to combine the evidence on the risk of injury when intoxicated with the diary data. Alternative assumptions are chosen to explore the implications of using national survey data. Results:Overall, an estimated 27% of road traffic accident (RTA) and 23% of non-RTA injuries in Britain are attributable to alcohol. AAF estimates for RTAs range from 54% to 2% and for non-RTAs from 36% to 8% in men aged 16-24 and women aged 55-64 respectively. Two potentially more realistic assumptions relating to the use of national survey data resulted in substantially lower AAF estimates for RTAs. Conclusion: Current methods of estimating injury AAFs using national survey data are flawed for some harms, particularly RTAs, where the data is not consistent with the epidemiological literature. Our findings indicate that the burden of injuries from RTAs in England has been previously overestimated. Further research into the prevalence of risky behaviours when intoxicated is required to refine these methods and produce more robust burden of injury estimates.