The association between exposure to childhood maltreatment and the development of atopic diseases
Childhood maltreatment affects over one in three children worldwide and is associated with substantial morbidity and mortality. The proposed proinflammatory effects of childhood maltreatment has been demonstrated to lead to disruption and shifts of T-helper 1 and 2 cells which may consequently lead to abnormalities in immune responses to environmental allergens. The association between childhood maltreatment and atopic disorders are not yet well understood. Of note, general practitioners play a vital role in the management of atopic disease in the community and also in the safeguarding of children at risk of maltreatment and so may be well positioned to support patients should there be any link. We aimed to explore the association between childhood maltreatment and atopy using the IQVIA medical research database, a large UK primary care database.
A population-based retrospective open cohort study was undertaken between January 1995 to September 2019. 238,986 patients with a code relating to childhood maltreatment or related concerns (exposed group) were matched to 681,376 unexposed controls by age, sex and deprivation. The primary outcome was defined by a GP recorded diagnosis of an atopic disease (asthma, atopic dermatitis or allergic rhinoconjunctvitis). The relative risk of developing atopy was described using adjusted incidence rate ratios (aIRR) with 95% confidence intervals (CI) presented.
At study entry, patients in the exposed group had an increased likelihood of having a diagnosis of asthma (adjusted odds ratio (aOR) 1.34: 95% CI 1.32 – 1.36) but a lower likelihood of atopic dermatitis (0.80: 95% CI 0.78 – 0.80) and allergic rhinoconjunctivitis (0.75: 95% CI 0.74 – 0.77) in comparison to the unexposed group. During the study period, 17,468 (IR 29.1 per 1,000 person years) patients in the exposed group developed an atopic disease compared to 48,811 (IR 24.4 per 1,000 person years). When considering confounders relating to the development of atopic disease this translated to an increased risk of aIRR 1.19 (95% CI 1.17 – 1.21); the strongest association was seen in asthma (aIRR 1.40, 95% CI 1.36 – 1.44). The findings must be considered in the context of their limitations. The main limitations revolve around misclassification of cases of childhood maltreatment. Although recent evidence suggest electronic health records have a high positive predictive value for identifying maltreatment, the prevalence in primary care data is substantially lower than national survey estimates.
Patients exposed to childhood maltreatment have an increased risk of developing atopy, with the highest risk seen in asthma. It is imperative that public health approaches, including those aimed at preventing and detecting childhood maltreatment and its associated negative consequences, are implemented in order to prevent subsequent ill health. Further research is needed to confirm these findings in other cohorts and also to explore the mechanistic pathways.