Investigating relationships between genetic risk, childhood maltreatment and eating disorders in women

Background Genetic and environmental factors contribute eating disorder risk, yet their interplay is poorly understood. We examine whether childhood maltreatment and polygenic scores for anorexia nervosa (PGS-AN) and binge-eating (PGS-BEB) are associated with eating disorders. We also examine interactions between childhood maltreatment and polygenic scores in predicting eating disorders. Methods This nested-case control study used data from up to 63,989 mothers in the Norwegian Mother, Father and Child Cohort Study. Mothers reported on their own experiences of four childhood maltreatment types: long-term humiliation or degradation, threats to self or close others, physical abuse, and sexual abuse. Diagnoses of AN, bulimia nervosa (BN), binge-eating disorder (BED), purging disorder (PD), and binge-eating spectrum disorders (BESP) were ascertained using self-report data from five timepoints and population health registers. Results The prevalence of AN, BN, BED, PD, and BESP was 2.19%, 4.15%, 10.39%, 0.60%, and 12.96%, respectively. All childhood maltreatment types were strongly associated with elevated eating disorder likelihood (odds ratios, ORs, ranged from 1.71 to 3.29), as were eating disorder polygenic scores (ORs ranged from 1.05 to 1.31). There were no multiplicative interaction effects between childhood maltreatment and polygenic scores. Small additive interactions were observed between PGS-AN and PGS-BEB and degradation/humiliation for BN and BESP in exploratory analyses. Conclusions Eating disorder polygenic scores and childhood maltreatment are associated with higher odds of eating disorders. Furthermore, we found tentative evidence of small additive interaction effects between polygenic liability and childhood maltreatment, suggesting that their combined influence further elevates the risk of some eating disorders.