Investigating relationships between genetic risk, childhood maltreatment and eating disorders

Importance: The associations between eating disorder polygenic scores and eating disorders areunclear. Furthermore, while both genetic and environmental factors contribute to thedevelopment of eating disorders, their interplay is poorly understood.Objective: This study extends prior research by examining whether childhood maltreatment andpolygenic scores for anorexia nervosa and binge-eating are associated with eating disorders. Wealso examine the interactions between childhood maltreatment and eating disorder geneticliability in predicting eating disorders.Design, Setting and Participants: This nested-case control study examined associations in up to63,989 mothers recruited from the Norwegian Mother, Father and Child Cohort Study (MoBa).Data were analysed from August 2023 to March 2025.Exposures: We indexed genetic liability to eating disorders using polygenic scores for anorexianervosa and binge-eating. Four types of childhood maltreatment were assessed: long-termhumiliation or degradation, threats to self or close others, physical abuse, and sexual abuseMain outcomes and Measures: Diagnoses of anorexia nervosa, bulimia nervosa, binge-eatingdisorder, purging disorder, and binge-eating spectrum disorders were ascertained using self-report data from five timepoints and population health registers.Results: The prevalence of anorexia nervosa, bulimia nervosa, binge-eating disorder, purgingdisorder, and binge-eating spectrum disorders was 2.19%, 4.15%, 10.39%, 0.60%, and 12.96%,respectively. Frequency of childhood maltreatment ranged from 4.25% (threatened) to 12.03%(degradation/humiliation). All forms of childhood maltreatment were strongly associated withelevated likelihood of eating disorders (odds ratios, ORs, ranged from 1.71 to 3.29), as wereeating disorder polygenic scores (ORs ranged from 1.05 to 1.31). There were no multiplicativeinteraction effects between childhood maltreatment and polygenic scores. Small additiveinteractions were observed between polygenic scores for anorexia nervosa and binge-eatingbroad and degradation/humiliation for bulimia nervosa and binge-eating spectrum disorders inexploratory analyses.Conclusions and Relevance: Our findings demonstrate that both eating disorder polygenicscores and childhood maltreatment are associated with higher odds of various eating disorders.Furthermore, our findings provide tentative evidence of small interaction effects betweenpolygenic liability and childhood maltreatment in predicting eating disorders, suggesting thattheir combined influence further elevates the risk of some eating disorders.