AIMS: To assess whether parental alcohol use disorder (AUD) is associated with higher risks of living in a non-intact family and assess whether non-intact family structure is associated with higher risks of AUD in the offspring.

DESIGN: Prospective cohort study.

SETTING: Danish nationwide registries.

PARTICIPANTS: 9,948 parental AUD offspring and 98,136 reference offspring from the Danish population.

MEASUREMENTS: Family structure assessed at birth and at each birthday until age 15 as intact or non-intact (with mother only, father only or neither parent). Years lived in an intact family defined as total number of years lived with both parents from birth until 15th birthday. AUD defined as registration in medical, treatment and cause of death registries. Data was analyzed by Cox regression.

FINDINGS: At birth, 30.9% (95% CI = 29.1-32.6) of parental AUD offspring and 10.7% (95% CI = 10.3-11.0) of reference offspring lived in a non-intact family. At age 15, the numbers were 84.6% (95% CI = 83.9-85.3) and 38.4% (95% CI = 38.1-38.7). Parental AUD was associated with a higher risk of offspring AUD (HR = 1.88, 95% CI = 1.74-2.02). Offspring were at lower risk of AUD if they lived 15 years in an intact family compared with offspring who never lived in an intact family (HR = 0.67, 95% CI = 0.52-0.87 for those with parental AUD, and HR = 0.53, 95% CI = 0.48-0.59 for those whose parents did not have AUD). Findings were inconclusive as to whether or not an association was present between family structure and AUD among offspring with parental AUD and reference offspring.

CONCLUSIONS: The prevalence of non-intact family structure appears to be higher in offspring of parents with alcohol use disorder (AUD) than among offspring from the general population. Parental AUD appears to be associated with increased risk of offspring AUD, and non-intact family structure appears to be associated with increased risk of offspring AUD regardless of parental AUD.