Educational inequality in the dietary approach to stop hypertension (DASH) diet in the UK: evaluating the mediating role of income

Apparentdifferences in the adoption of the Dietary Approach to Stop Hypertension (DASH) diet havebeen reported between less and moreeducated individuals. However, the mediatingrole of income hasnot been clarified. In this study, we aimed at quantifyingthe mediating effect of income on the relationship between education and the DASH score in the UK population. We analyzeddata on 4864subjects aged 18yearsand older collected inthree waves of theNational Diet and Nutrition Survey (NDNS 2008-2016). The DASH score was calculated using sex-specific quintiles of DASH items. We carried out a counterfactual-based mediation analysis todecompose the total effect of education on DASH score into average direct effect (ADE) and average causal mediation effect (ACME) mediated by income. We found that the overall mediating effect of income on the relationship between education and the DASH score was only partial, with an estimated proportion mediated ranging between 6 to 9%. The mediating effect was higher among females(11.6%) and younger people (17.9%). Further research is needed to investigate which other factors may explain the socioeconomic inequality in the adoption of the DASH diet in UK