Heterogeneous effects of increased availability of alcohol on hospitalization due to external causes: quasi-experimental evidence from the introduction of Saturday opening at Swedish alcohol retail stores.

Responses to increased alcohol availability may vary across the population as a function of differential vulnerability. This study therefore aimed to examine the effects of the implementation of Saturday opening at the Swedish alcohol retail monopoly in 2000 on risks of hospitalization due to external causes (HEC) among different population subgroups. Leveraging the experimental design of the reform, longitudinal difference-in-differences analyses were applied to a register-based cohort of individuals aged 20-40 at the time of implementation. The population was stratified into groups of Swedish, Finnish, and Middle Eastern origin, known to represent different levels of alcohol consumption and rates of alcohol-related morbidity. Results showed a 17.7% increase (P < .029) in the risk of HEC among individuals of Finnish origin, as jointly caused by both increased prevalence in the experiment area and decreased prevalence in the control area. The increase was primarily driven by younger men with lower levels of education. Those of Swedish origin exhibited largely similar patterns (9.7% increase; P < .001), while no measurable impact was observed among individuals of Middle Eastern origin (-21.4% decrease; P < .076). The findings confirm that increasing alcohol availability contributes to the disease burden related to alcohol among population subgroups already susceptible to its effects.