Beyond BMI: Personality Traits’ Associations With Adiposity and Metabolic Rate

Abstract

Various personality traits are known to correlate with body mass index (BMI). However, rarely have studies looked beyond BMI to understand how adiposity and other metabolic characteristics relate to psychological traits. We explored personality traits’ phenotypic and genetic associations with basal metabolic rate (BMR) and an improved index of adiposity—relative fat mass (RFM)—and assessed how personality traits’ associations with RFM differ from their associations with BMI. In a subsample of the Estonian Biobank (N = 3,535), we correlated RFM, BMI, and BMR, as well as their polygenic scores, with the five domains and 30 facets of NEO Personality Inventory-3. Various traits, notably Openness and its facets, associated with RFM above and beyond BMI. Assertiveness consistently correlated with BMR, mirroring associations with conceptually similar traits in non-human animals, but not with RFM as may have been expected based on previous studies. Genetic analyses suggested that some personality trait–metabolic marker associations have genetic bases while others may be environmental in origin. The use of BMI can lead to both attenuated and inflated estimates of personality trait–adiposity associations. Personality traits may be involved in the development of overweight, but metabolic variables may additionally contribute to differences in personality traits.