Association between childhood adversity and use of the health, social, and justice systems in Denmark (DANLIFE): a nationwide cohort study.

Background: Childhood adversities can negatively affect health and social outcomes. We aimed to assess the association between adversity in childhood and use of public services in early adulthood across three systems: health, social welfare, and justice.

Methods: We used Danish nationwide registry data on individuals born between 1980 and 1991 and followed up between 1998 and 2021. We evaluated annual exposure to adversity during childhood (age 0-16 years) across three dimensions-material deprivation, loss or threat of loss within the family, and family dynamics-and used this to divide individuals into five trajectory groups: low adversity, early-life material deprivation, persistent material deprivation, loss or threat of loss, and high adversity. We defined high-intensity users of each public service system as those above the 90th percentile in terms of hospital visits (health system) and weeks of social welfare use (social welfare system), and whether or not they were convicted for a crime (justice system) during early adulthood (age 18-40 years). We analysed the proportion of high-intensity users of each public service system across the childhood adversity trajectory groups. Logistic regression was used to assess whether the risk of becoming a high-intensity user differed by trajectory group relative to the low-adversity group, with adjustment for sex, parental education, parental origin, and maternal age at time of birth.

Findings: Of the 567 035 individuals in the cohort, 273 616 (48·3%) were in the low-adversity group, 128 238 (22·6%) were in the early-life material deprivation group, 100 959 (17·8%) were in the persistent material deprivation group, 43 826 (7·7%) were in the loss or threat of loss group, and 20 396 (3·6%) were in the high-adversity group. Childhood adversity was associated with a markedly higher risk of belonging to the high-intensity user group across all three public service systems. Specifically, low proportions of the low-adversity group became high-intensity users of the health system (19 675 [7·2%]), social welfare system (13 681 [5·0%]), and justice system (38 198 [14·0%]). By comparison, those in the high-adversity group were significantly more likely to become high-intensity users of the health system (4685 [23·0%]; adjusted odds ratio 2·81 [95% CI 2·71-2·93]), social welfare system (8158 [40·0%]; 8·88 [8·50-9·27]), and justice system (8681 [42·6%]; 3·62 [3·50-3·75]).

Interpretation: There were long-term effects of childhood adversities across three public service systems, with an association of high-intensity users among individuals who experienced childhood adversity. Systemic inequalities already present in childhood need to be addressed, with prioritisation of equitable resource allocation for those most in need of assistance.

Funding: Rockwool Foundation.