Multiple adverse childhood experiences and asthma onset in adulthood: Role of adulthood risk factors as mediators.

Objective: This population-based study of 21,902 Finnish adults examined whether adulthood risk factors for asthma mediate the association between the exposure to multiple adverse childhood experiences (ACEs) assessed retrospectively and the risk of new-onset asthma in adulthood.

Methods: Baseline characteristics, occurrence of ACEs, and risk factors of asthma in adulthood were collected with a postal survey at baseline in 1998. The participants were linked to records on incident asthma from national health registers from 1999 to 2012. Counterfactual mediation analysis was used to examine the effects of multiple ACEs (≥2) on asthma through adulthood risk factors of asthma (mediators).

Results: Of the 21,902 participants without asthma at baseline, 7552 (34%) were exposed to multiple ACEs during childhood. During the follow-up period, 2046 participants were diagnosed with incident asthma. Exposure to multiple ACEs increased the risk of asthma onset by 31% compared with ≤1 ACE. The association between ACEs and asthma onset was partly mediated by the following adulthood risk factors: severe life events (29%), smoking (15%), allergic rhinitis (8%), low education level (6%), and obesity (3%). Specific stressful life events mediating the ACE-asthma association were 'severe financial difficulties' (24%), 'emotional, physical or sexual violence' (15%), 'major increase in marital problems' (8%), 'severe conflicts with supervisor' (7%), and 'divorce or separation' (5%).

Conclusions: Exposure to multiple ACEs increased the risk of asthma in adulthood. Adulthood risk factors of asthma mediated a significant proportion of the effect of ACEs on the risk of asthma onset.