Parental feeding and childhood genetic risk for obesity: Exploring hypothetical interventions with causal inference methods

Parental feeding behaviors are common intervention targets for childhood obesity, but often only deliver small changes. Childhood BMI is partly driven by genetic effects, and the extent to which parental feeding interventions can mediate child genetic liability is not known. Here we aim to examine how potential interventions on parental feeding behaviors can mitigate some of the association between child genetic liability and BMI in early adolescence, using causal inference based methods. Data were from the Avon Longitudinal Study of Parents and Children and we quantified the interventional disparity measure of child genetic risk for BMI (PRS-BMI) on objectively BMI at 12 years, if we were to intervene on parental feeding styles measured when children were 10-11 years (n=4,248). Results are presented as Adjusted Total Association (Adj-Ta) between genetic liability and BMI at 12 years, versus the Interventional Disparity Measure Direct Effect (IDM-DE), which represents the association, that would remain, had we intervened on the parental feeding. For children with the top quintile of genetic liability, an intervention shifting parental feeding to the levels of children with lowest genetic risk, resulted in a difference of 0.81 kg/m 2 in BMI at 12y (Adj-Ta= 3.27, 95%CI: 3.04, 3.49; versus IDM-DE=2.46, 95%CI: 2.24, 2.67). Findings suggest that parental feeding interventions have the potential to buffer some of the genetic liability for childhood obesity. Further, we highlight a novel way to analyze potential interventions for health conditions only using secondary data analyses, by combining methodology from statistical genetics and social epidemiology.