The mediation effect of individual eating behaviours on the relationship between socioeconomic status and dietary quality in children: the Korean National Health and Nutrition Examination Survey

PURPOSE Although it has been suggested that socioeconomic status is associated with dietary quality, the possible mediation effects of eating behaviours on dietary quality are unclear. Thus, we investigated the causal chain by which socioeconomic status influences the quality of the diets consumed by children through their eating behaviours using data from the Korean National Health and Nutrition Examination Survey. METHODS The study focused on persons from 2 to 18 years of age who completed the 24-h dietary recall survey (n = 3158). Using causal mediation analysis, we assessed the relationship between socioeconomic status and poor dietary quality in children and examined the mediation effects of eating behaviours. Socioeconomic indicators included household income, parental education, and parental occupation. Dietary quality was defined by the number of key nutrients, protein, calcium, phosphorous, iron, vitamin A, vitamin B1, vitamin B2, niacin, and vitamin C, consumed at insufficient levels. RESULTS In the present study, more than half the children did not consume the recommended amounts of vitamin A, vitamin C, iron, and calcium. Eating breakfast had a significant impact on poor dietary quality regardless of socioeconomic indicators. On the other hand, children from lower-middle-income households consumed insufficient amounts of more nutrients than their counterparts regardless of eating behaviours. Through the mediation model, we found that lower-middle household incomes were associated with poor dietary quality, but that dietary quality was significantly mediated by eating breakfast. CONCLUSION We found that poor dietary quality among children in lower-income households was partially explained by their being less likely to eat breakfast, but that eating breakfast did not entirely mediate these effects. Thus, to reduce differences in dietary quality among children, those who are economically vulnerable must be prioritized.