Heterogenous Trajectories in Physical, Mental and Cognitive Health among Older Americans: Roles of Genetics and Earlier SES

Abstract

We investigate the roles of genetic predispositions, childhood SES and adult schooling attainment in shaping trajectories for three important components of the overall health and wellbeing of older adults -- BMI, depressive symptoms and cognition. We use the Health & Retirement Study (HRS) and group-based trajectory modelling (GBTM) to identify subgroups of people who share the same underlying trajectories over ages 50-94 years. After identifying common underlying trajectories, we use fractional multinomial logit models to estimate associations of (1) polygenic scores for BMI, depression, ever-smoked, education, cognition and subjective wellbeing, (2) childhood SES and (3) schooling attainment on the probabilities of trajectory group membership. While genetic predispositions do play a part in predicting trajectory group membership, our results highlight the long arm of socioeconomic factors. Schooling attainment is the most robust predictor—it predicts increased probabilities of belonging to trajectories with BMI in the normal rage, low depressive symptoms and high initial cognition. Childhood circumstances are manifested in trajectories to a lesser extent, with childhood SES only predicting the likelihood of being on the low depressive symptoms trajectory. We also find suggestive evidence that associations of schooling attainment on the probabilities of being on trajectories with BMI in the normal rage, low depressive symptoms and high initial cognition vary with genetic predispositions.