Stress-Related Poor Diet Quality Does Not Explain Socioeconomic Inequities in Health: A Structural Equation Mediation Analysis of Gender-Specific Pathways

Abstract

Background: Psychosocial stress and diet quality individually mediate associations between socioeconomic position (SEP) and health; however, it is not known whether they jointly mediate these associations. This is an important question because stress-related unhealthy eating is often invoked as an explanation for diet-related health inequities, particularly among women, seemingly with no empirical justification.

Objective: This study examined whether psychosocial stress and diet quality jointly mediated associations between SEP and self-rated health in women and men.

Design: Multiple mediating pathways were modeled using data from the cross-sectional International Food Policy Study.

Participants and setting: Data were collected from 5,645 adults (aged 18 years or older) in Canada during 2018 and 2019.

Main outcome measures: Participants reported SEP using indicators of materialist (educational attainment and perceived income adequacy) and psychosocial pathways (subjective social status), along with psychosocial stress, dietary intake (to assess overall diet quality via Healthy Eating Index-2015 scores), and self-rated health.

Statistical analyses performed: Structural equation modeling modeled pathways linking SEP (ie, educational attainment, perceived income adequacy, and subjective social status) with self-rated health mediated by psychosocial stress and diet quality, stratified by gender.

Results: There was no evidence that psychosocial stress and diet quality jointly mediated associations between SEP and self-rated health in women or men. Diet quality mediated associations between educational attainment and self-rated health in women and men, with some evidence that it mediated associations between subjective social status and self-rated health in men (P = 0.051). Psychosocial stress mediated associations between perceived income adequacy and self-rated health in women and men, and between subjective social status and self-rated health in women.

Conclusions: Although often invoked as an explanation for diet-related health inequities, stress-related poor diet quality did not mediate associations between SEP and self-rated health in women or men. Psychosocial stress and diet quality individually mediated some of these associations, with some differences by gender.

Keywords: Diet quality; Health inequities; Materialist perspective; Psychosocial perspective; Psychosocial stress.