Association of Youth Age at Exposure to Household Dysfunction With Outcomes in Early Adulthood

IMPORTANCE: The current focus on the association of negative experiences in early childhood with adverse outcomes later in life is based on limited empirical evidence. OBJECTIVE: To evaluate whether age at exposure to negative experiences in childhood and adolescence is associated with outcomes in early adulthood. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used population data from administrative sources for all Danish individuals born between 1987 and 1995 who were living in Denmark at 19 years of age. Data were analyzed in July 2020. EXPOSURES: Exposure to 6 household dysfunction items (HDIs) from birth to 17 years of age by age group. Age groups were as follows: 0 to 2 years (early childhood), 3 to 5 years (preschool), 6 to 12 years (mid-childhood), and 13 to 17 years (early adolescence). The 6 items were parents’ unemployment, incarceration, mental disorders, death, and divorce and the child’s foster care experiences. MAIN OUTCOMES AND MEASURES: Mental disorders, low educational attainment, disconnection from education and the labor market, and criminal charges. A fixed-effects model was used to estimate the dose-response and age-specific associations between HDI exposure and the collated outcome measure. RESULTS: The study sample included 605 344 individuals observed from birth to 19 years of age (mean [SD] birth year, 1991 [2.56] years; range, 1987-1995; 335 725 [55%] male). Overall, 278 115 individuals (45.94%) were exposed to 1 or more of the 6 HDIs from birth to 17 years of age. Exposure was most prevalent at 1 year of age (exposure rate, 11.3%), and parental unemployment was the most common HDI (15.5% observed in mid-childhood). The risk of experiencing the 4 outcomes was monotonically associated with the number of HDIs. For example, experiencing 1 HDI between birth and 17 years of age was associated with an increased risk of experiencing an adverse outcome by approximately 1.0 percentage point (β = 0.011; 95% CI, 0.010-0.012; P < .001). Similarly, the risk of experiencing adverse outcomes varied significantly in association with age at exposure. Exposure during early adolescence was more strongly associated with adverse outcomes than was exposure during early childhood (increased risk of 5.8 percentage points [β = 0.058; 95% CI, 0.052-0.063; P < .001] vs 1.0 [β = 0.010; 95% CI, 0.004-0.015; P = .001]). CONCLUSIONS AND RELEVANCE: In this cohort study, exposure to negative experiences in early adolescence was more strongly associated with later adverse outcomes than was exposure at other points in childhood. Knowledge of age-specific associations is important information for policy makers who need to prioritize resources targeting disadvantaged children and youths.