Fig. 2
Theoretical framework and pathway diagram for examining the mediating role of adolescent COM in associations between SEP in adolescence and diet quality in early adulthood based on Capability, Opportunity, Motivation and Behaviour (COM-B) model
The Endogenous variables (dependent) are diet quality and COM. Parental education and area-level disadvantage are each used as indicators of SEP in separate models. COM represent potential mediators at baseline (latent variables) on the pathway between SEP at baseline (measured variable) and diet quality at T3 (measured variable). In this COM model, Capability was a latent variable designed to represent food-related activities and skills, Opportunity was a latent variable designed to represent availability of fruit and vegetables in the home, and Motivation was a latent variable designed to represent confidence that one can eat healthily (self-efficacy). The indirect mediated effects of SEP on diet quality through Capabilities, Opportunities and Motivations (indirect paths – represented by dashed line) were estimated by multiplying the a-path effects of SEP on each mediator (paths a1-3) by the b-path effect of each mediator on diet quality (paths b1-3). The individual mediating effect of Capability, Opportunity and Motivations, as well as the joint mediating effects (Opportunity -> Capability -> Motivation) in associations between SEP and diet quality were estimated. The total effect between SEP and diet quality is represented by path c. T, timepoint