Anorexia nervosa polygenic risk, beyond diagnoses: relationship with adolescent disordered eating and behaviours in an Australian female twin population

Abstract

BackgroundIt is well established that there is a substantial genetic component to eating disorders. Polygenic risk scores (PRS) can be used to quantify cumulative genetic risk for a trait at an individual level. Recent studies suggest PRS for Anorexia Nervosa (AN) may also predict risk for other disordered eating behaviours, but no study has examined if PRS for AN can predict disordered eating as a global continuous measure. This study aimed to investigate whether PRS for AN predicted overall levels of disordered eating, or specific lifetime disordered eating behaviours, in an Australian adolescent female population.MethodsPRS were calculated based on summary statistics from the largest Psychiatric Genomics Consortium AN genome-wide association study to date. Analyses were performed using GCTA to test the associations between AN PRS and disordered eating global scores, avoidance of eating, objective bulimic episodes, self-induced vomiting, and driven exercise in a sample of Australian adolescent female twins recruited from the Australian Twin Registry (N = 383).ResultsAfter applying the false discovery rate correction, the AN PRS was significantly associated with all disordered eating outcomes.ConclusionsFindings suggest shared genetic aetiology across disordered eating presentations and provide insight into the utility of AN PRS for predicting disordered eating behaviours, and individuals at risk, in the general population. In the future, PRSs for eating disorders may have clinical utility in early disordered eating risk identification, prevention, and intervention.