Objective A link between adverse childhood experience (ACE) in early life and subsequent asthma is suggested, but existing studies are often based on parent-reported data for both exposure and outcome. We aimed to examine the association of ACE in early life (bereavement, parental chronic somatic illness, or psychiatric illness/suicide attempt) with childhood asthma, using registry information of exposures and outcome.

Methods We used registry data of 466 556 children born in Denmark, 1997–2004. ACE and asthma diagnosis or medication was obtained from the Danish National Patient or Prescription Registry. We used multinomial logistic regression to examine the association between ACE in early life and phenotypes of childhood asthma, which we empirically estimated using group-based trajectory modeling. We adjusted for year of birth, maternal age, smoking, place of living, parity, parental education and atopic status; we imputed missing data using multiple imputations with chained equations.

Results We identified four asthma trajectories: early onset (before age 3) transient asthma, late onset (3 years or later) asthma, early onset persistent asthma, and never/infrequent asthma. Girls exposed to at least one ACE before the age of 2 years, compared to the non-exposed, had higher odds of being assigned to the early-onset transient asthma group (odds ratio (OR) 1.13 [95% Confidence Interval (CI): 1.04–1.24]), the late-onset asthma group (OR 1.28 [95% CI: 1.11–1.48]) or the early-onset persistent asthma group (OR 1.27 [95% CI: 1.08–1.48]) compared to the never/infrequent asthma group. Similar results were seen for boys, OR 1.16 [95% CI: 1.08–1.25], OR 1.11 [95% CI: 0.98–1.25], and OR 1.34 [95% CI: 1.20–1.51] respectively. The odds remained largely the same in imputed and unadjusted models.

Conclusion In a Danish nationwide population four asthma trajectories were identified, in agreement with clinical studies. ACE in early life was associated with all asthma phenotypes for both boys and girls.