Impacts of the minimum legal drinking age legislation on in-patient morbidity in Canada, 1997-2007: a regression-discontinuity approach.

Aims: To provide novel, population-based estimates of the influence of minimum legal drinking age (MLDA) legislation on target in-patient hospital events in Canada.

Design: Regression-discontinuity analyses on rates of Canadian in-patient admissions.

Setting: All in-patient hospitalizations in Canada (except Québec) between 1 April 1997 and 31 March 2007.

Participants: Individuals aged 15-22 years admitted to hospital.

Measurements: International Classification of Diseases-9/10 codes for alcohol-use disorders/poisoning, injury, suicide, assault and motor vehicle accidents were considered as target morbidity conditions.

Findings: Compared with the baseline hospitalization rate just prior to the MLDA, admissions at the MLDA rose significantly (P ≤ 0.001) for alcohol-use disorders/poisoning for males (17.3%) and females (21.1%), as well as for suicide events for the combined sample (9.6%, P = 0.029). Among males, there was a significant 4.4% increase (P = 0.001) in a broad class of injuries, including a 9.2% jump (P = 0.020) in admissions for motor vehicle accidents compared with the baseline hospitalization rate just prior to the MLDA.

Conclusion: Removal of minimum legal drinking age restrictions is associated with significant population-level increases in hospital admissions among young adults in Canada for alcohol-use disorders/poisoning, as well as for other serious injuries, especially among males. Current international minimum legal drinking age policy discussions should account for the impact of the minimum legal drinking age on severe morbidity outcomes.