Understanding the mental health consequences of child maltreatment at different life stages is important in accurately quantifying the burden of maltreatment. This study investigated the association between child maltreatment and incident mental disorders in middle and older age as well as the potential mediators and moderators.
This is a retrospective cohort study of 56,082 participants from UK Biobank. Child maltreatment was recalled using the Childhood Trauma Screener. Incident mental disorders, including depressive, anxiety and affective disorders, behavioural syndromes, post-traumatic stress disorder (PTSD), schizophrenia, substance abuse, and dementia, after baseline assessment were ascertained through linkage to primary care records.
There was a dose-response relationship between child maltreatment and mental disorder. Those who experienced three or more maltreatment types had the highest risk of all mental disorders (HR 1.85, 95% CI: 1.67-2.06) followed by those who experienced two (HR 1.48, 95% CI: 1.35-1.63) and then one (HR 1.26, 95% CI: 1.19-2.35). Child maltreatment was most strongly associated with PTSD (HR 1.59, 95% CI: 1.20-2.10 P=0.001). The excess risk was largely unexplained by the included mediators. The association between child maltreatment and all mental disorders were stronger among participants who binge drank (Pinteraction=0.003) or had few social visits (Pinteraction=0.003).
The mental health consequence of child maltreatment could last decades, even among those who had no recorded mental disorders in early adulthood. In the absence of strong mediators, prevention of child maltreatment remains the priority.
Wellcome Trust Institutional Strategic Support Fund
]. Child maltreatment, which comprises physical, emotional, and sexual abuse as well as neglect, is a major component of ACEs. Globally over 1 billion children and adolescents experience violence, and many more cases go unreported [
] with a dose-response relationship. In a recent meta-analysis, participants with at least four ACEs had a higher risk of all adverse health outcomes; with strong associations shown for mental disorders, in particular depression (OR=4.4) and anxiety (OR=3.7) [
]. However, many of the existing studies were subject to numerous limitations. For example, retrospective cohort studies often used prevalent outcomes, which could substantially distort the exposure-outcome associations since prevalent mental disorders could affect maltreatment recall [
]. The issue of reverse causation is particularly difficult to disentangle for early-onset mental disorders and there is a lack of evidence focusing on mental disorders that were firstly diagnosed in middle and older age.
]. There were also preliminary studies suggesting the potential mediating roles of systematic inflammation [
] and cardiovascular biomarkers [
The current study, therefore, aims to investigate the association between child maltreatment and the onset of a wide range of physician-diagnosed mental disorders in middle and older age, as well as potential mediating and moderating factors.
2.1 Study design and participants
UK Biobank recruited 502,493 participants aged 37-73 years (5.5% response rate) who were assessed at 22 centres across England, Scotland, and Wales between 2007 and 2010 as a general population-based cohort. UK Biobank received ethical approval from the North West Multi-Centre Research Ethics Committee (REC reference: 11/NW/03820).
]. The International Physical Activity Questionnaire (IPAQ) was used to assess physical activity levels [