Educational attainment and genetic liability to overweight: Body mass index across the adult life course in females and males

Abstract Background and Aim Socioeconomically disadvantaged people are more likely to have high body mass index (BMI). However whether socioeconomic position moderates genetic susceptibility to high BMI, and whether this effect differs by sex, remains unclear. We aimed to investigate whether educational attainment (EA) moderates the association between genetic liability for high BMI and BMI trajectories across adulthood in females and males. Methods We analyzed data from 69,314 participants in the Trøndelag Health Study (HUNT), a population-based cohort with genotyping and repeated BMI measures. A polygenic index for BMI (BMI PGI) was calculated, and participants were categorized by EA level. Using linear mixed-effects models stratified by sex, we tested the interaction between BMI PGI, EA, and age on BMI trajectories. Results The relationship between BMI PGI and BMI was non-linear, showing a steeper slope in the upper deciles, and was modified by sex ( p