Practical Nutrition Knowledge Mediates the Relationship Between Sociodemographic Characteristics and Diet Quality in Adults: A Cross-Sectional Analysis.

Purpose: To investigate the direct and indirect effects of sociodemographic/health factors on diet quality through practical nutrition knowledge (PNK) about how to compose a balanced meal.
Design: A cross-sectional study using data from an online survey of the 10 000 Steps cohort (data collected November-December 2016).
Setting: Australia.
Participants: Adults (n = 8161). Response rate was 16.7%.
Measures: Self-reported lifestyle, health, and sociodemographic characteristics, including diet quality and PNK.
Analysis: The PROCESS macro for SPSS was used to conduct the mediation analyses.
Results: Better diet quality was associated with being female, older, more highly educated, and having a lower body mass index. Mediation analysis showed that PNK significantly mediated the associations between sex (a*b = 0.54, 95% confidence interval [CI] = 0.39-0.70) and education (vocational education: a*b = 0.22, 95% CI = 0.12-0.35, university: a*b = 0.48, 95% CI = 0.35-0.64), and diet quality. Practical nutrition knowledge suppressed the association between age and diet quality (a*b = -0.03, 95% CI = -0.04 to -0.03).
Conclusion: Variations in diet quality between sociodemographic groups were partially explained by differences in PNK, suggesting that focusing public health efforts on increasing this specific knowledge type might be promising.