Associations Between Nutrition Knowledge and Overall Diet Quality: The Moderating Role of Sociodemographic Characteristics-Results From the PREDISE Study

Purpose: To assess how nutrition knowledge is associated with global diet quality and to investigate whether sociodemographic characteristics (ie, sex, age, education, income, marital status, and living with children or not) moderate this association. Design: Cross-sectional web-based study. Participants: The PREDISE study aims at identifying correlates of adherence to healthy eating guidelines in French-speaking adults from the Province of Quebec, Canada. Subjects: A probability sample of 1092 participants (50% female). Measures: The Nutrition Knowledge Questionnaire and 24-hour food recalls from which the Canadian Healthy Eating Index (C-HEI) was calculated. Analysis: Multiple linear regressions performed to assess how nutrition knowledge is associated with the C-HEI. Interaction terms tested to evaluate whether sociodemographic characteristics moderate the association between nutrition knowledge and the C-HEI. Results: Nutrition knowledge (B = 0.141 [95% CI: 0.075-0.208],P< .0001) was identified as a significant correlate of the C-HEI. Education significantly moderated the association between nutrition knowledge and the C-HEI (Pinteraction = .0038), with a significative association among participants with a lower education level (B = 0.295 [95% CI: 0.170-0.421],P< .0001) but not among participants with a higher education level (B = 0.077 [95% CI: -0.004 to 0.157],P= .06). Whether participants lived with or without children also significantly moderated the association (Pinteraction = 0.0043); nutrition knowledge was associated with the C-HEI only in participants who were not living with children (B = 0.261 [95% CI: 0.167 to 0.355],P< .0001). Conclusion: This study suggests that the association between nutrition knowledge and adherence to healthy eating guidelines is not the same in different subgroups of the population. Interventions aiming at increasing nutrition knowledge may be a promising approach to improve diet quality, especially among individuals with a lower education.