The impact of anorexia nervosa and BMI polygenic risk on childhood growth: a 20-year longitudinal population-based study

Abstract

BackgroundDeviating growth from the norm during childhood has been associated with anorexia nervosa (AN) and obesity later in life. In this study, we examined whether polygenic scores (PGSs) for AN and BMI are associated with growth trajectories spanning the first two decades of life. MethodsAN-PGS and BMI-PGS were calculated for participants of the Avon Longitudinal Study of Parents and Children (ALSPAC; N=8,654). Using generalized (mixed) linear models, we associated PGSs with trajectories of weight, height, body mass index (BMI), fat mass index (FMI), lean mass index (LMI), and bone mineral density (BMD). ResultsFemale participants with one SD higher AN-PGS had on average 0.004% slower growth in BMI between the ages 6.5-24 years and a 0.4% slower growth in BMD between the ages 10-24 years. Higher BMI-PGS was associated with faster growth for BMI, FMI, LMI, BMD, and weight trajectories in both sexes throughout childhood. Female participants with both a high AN-PGS and a low BMI-PGS showed slower growth compared to those with both a low AN-PGS and a low BMI-PGS. ConclusionAN-PGS and BMI-PGS have detectable sex-specific effects on growth trajectories. Female participants with high AN-PGS and low BMI-PGS likely constitute a high-risk group for AN as their growth was slower compared to their peers with high PGS on both traits. Further research is needed to better understand how the AN-PGS and the BMI-PGS co-influence growth during childhood and whether high BMI-PGSs can mitigate the effects of a high AN-PGS.