Child Maltreatment Characteristics and Adult Physical Multimorbidity in Germany.

Importance: Associations between child maltreatment (CM) and health have been studied broadly, but most studies focus on multiplicity (number of experienced subtypes of CM). Studies assessing multiple CM characteristics are scarce, partly due to methodological challenges, and were mostly conducted in patient samples. Objective: To determine the importance of CM characteristics in association with physical multimorbidity in adulthood for women and men in a German representative sample. Design, Setting, and Participants: This survey study used data from a representative sample of the German population between July and October 2021. Households were randomly selected within regional areas by a German demographic consultation company, and the Kish-Grid method was applied to ensure random participation. Reasons for nonparticipation were refusal of the selected household or target person to participate and failure to contact a household after 4 visits. Analyses took place between June 2023 and July 2024. Exposure: Characteristics of CM, including subtypes of CM, multiplicity, age at time of maltreatment (timing), number of years of experienced maltreatment (duration), frequency, and subjective severity (measured with the ISPCAN Child Abuse Screening Tools Retrospective version questionnaire). Main Outcomes and Measures: The main outcome was physical multimorbidity, defined as the sum score of lifetime leading morbidity and mortality causes in Western countries (obesity, diabetes, cancer, hypertension, myocardial infarction, chronic obstructive pulmonary disease, and incident stroke). Conditioned random forest regression analyses (a machine learning regression technique) were conducted to examine what characteristics of CM were most importantly associated with physical multimorbidity in adulthood while considering all other variables in the model. Results: Of 5908 individuals invited, the study sample included 2514 participants (response rate, 42.6%), with 1297 (51.6%) women (mean [SD] age, 50.6 [17.9] years) and 1217 (48.4%) men (mean [SD] age, 49.5 [18.2] years). Duration of CM was the most important factor for physical multimorbidity in adulthood for both women (importance = 0.595; 95% CI, 0.599-0.601) and men (importance = 1.389; 95% CI, 1.386-1.394). Duration and timing variables were more importantly associated with outcomes than multiplicity in women and men. For women, severity and experiencing CM at age 4 years was significantly associated with physical multimorbidity in adulthood. For men, experiencing CM at age 11 years was most importantly associated with physical multimorbidity in adulthood. Conclusions and Relevance: In this survey study, conditioned random forest regression analyses were applied to provide insights in the importance of duration and timing of CM for physical health in addition to the frequently studied multiplicity. These findings suggest that CM assessments should be considered in diagnostics of individuals with physical health conditions and may also inform strategies to mitigate the risk.