The risk of offspring developing substance use disorders when exposed to one versus two parent(s) with alcohol use disorder: A nationwide, register-based cohort study

Aim: Few population-based, family studies have examined associations between exposure to one vs. two parent(s) with alcohol use disorder (AUD) and the risk of offspring developing substance use disorder (SUD). Moreover, these studies have focused solely on the development of AUD, and not SUD, in offspring. The purpose of this study was to investigate whether exposure to one vs. two parent(s) with AUD increases the risk of offspring developing SUD. Methods: A population-based, cohort study was conducted in which offspring born in Denmark between 1983 and 1989 were followed through national registries until 2011. Register-based data were obtained from the: Psychiatric Central Research Register, National Patient Registry, Civil Registration System, Fertility Database, and Cause of Death Register. Adjusted hazard ratios were calculated using multivariate Cox-regression models. Findings: A total of 398,881 offspring were included in this study. Of these, 3.9% had at least one parent with AUD. Parental AUD was significantly associated with the development of SUD in offspring. Having one parent with AUD was linked to a 1.44-fold increased risk (95% CL, 1.29-1.61), while having two parents with AUD was linked to a 2.29-fold increased risk (95% CI, 1.64-3.20). No significant differences were found in relation to either parental or offspring gender. Conclusions: Exposure to parental AUD is linked to an increased risk of offspring developing SUD. This risk is additive for offspring exposed to double parental AUD. The findings have important implications for clinical assessment and intervention strategies, as well as the management of offspring exposed to parental AUD.