Triangulation of evidence on immigration and rates of alcohol use disorder in Sweden: Evidence of acculturation effects

Background: This study aimed to determine the robustness of the impact of immigration on risk for alcohol use disorder (AUD) using different measures, designs, and immigrant regional cohorts. Methods: The analytic sample included all individuals born between 1950 and 1990 and registered in Sweden from 1973 to 2017. Using Cox regression models, we examined the risk for AUD from Swedish nationwide registries in immigrants to Sweden from seven geographical regions: Africa, Asia and Oceania, Eastern Europe, Finland, Latin America and the Caribbean, Middle East/North Africa, and Western countries. We assessed greater exposure to Swedish culture, which we interpreted as increasing acculturation, by (i) comparing first-generation immigrants and their children with no and one native Swedish parent and (ii) examining age at immigration. The baseline comparison group was the native Swedish population. We also examined AUD risk in first-generation sibling pairs discordant for their age at immigration. Results: In nearly all immigrant cohorts in Sweden, increasing degrees of acculturation, as assessed by both our variables, were associated with rates of AUD that approached those of the Swedish population. These findings occurred in both men and women and both regional cohorts whose first-generation immigrants had lower and higher levels of AUD than native-born Swedes. For most cohorts, the rates of change with acculturation were greater in women than in men. In sibling pairs from most regions, the sibling who was younger at immigration had a higher rate of AUD. Conclusions: An examination of both sexes and two different proxies for acculturation provides consistent support for socio-cultural influences on AUD risk. Our co-sibling analyses suggest that a meaningful proportion of this effect is likely to be causal in nature.