Polygenic score for body mass index is associated with disordered eating in a general population cohort

Background Disordered eating (DE) is common and is associated with body mass index (BMI). We aimed to investigate if genetic variants for BMI were associated with DE. Methods BMI polygenic scores (PGS) were calculated for participants of the Avon Longitudinal Study of Parents and Children (ALSPAC; N= 8,654) and their association with DE tested. Data on DE behaviors (e.g. binge eating, and compensatory behaviors) were collected at ages 14, 16, 18 years, and DE cognitions (e.g. body dissatisfaction) at 14 years. Mediation analyses determined whether BMI mediated the association between the BMI-PGS and DE. Results The BMI-PGS was positively associated with fasting (OR= 1.42, 95% CI=1.25, 1.61), binge eating (OR=1.28, 95% CI= 1.12, 1.46), purging (OR= 1.20, 95% CI= 1.02, 1.42), body dissatisfaction (Beta= 0.99, 95% CI= 0.77, 1.22), restrained eating (Beta=0.14, 95% CI= 0.10, 1.17), emotional eating (Beta= 0.21, 95% CI= 0.052, 0.38), and negatively associated with thin ideal internalization (Beta= −0.15, 95% CI= −0.23, −0.07) and external eating (Beta= −0.19, 95% CI= −0.30, −0.09). These associations were mainly mediated by BMI. Conclusions Genetic variants associated with BMI are also associated with DE. This association was mediated through BMI suggesting that weight potentially sits on the pathway from genetic liability to DE.