Healthy Eating Index-2020 and post-stroke depression (PSD): cross-sectional analysis of NHANES data.
TL;DR
HEI-2020 was inversely associated with PSD, with nonlinear and race-specific patterns and DI-GM showed a significant but inconsistent indirect association, suggesting a suppressive rather than mediating role.
Abstract
Background
Post-stroke depression (PSD) is a common complication after stroke and contributes to poor functional recovery and reduced quality of life. Dietary quality has been associated with depression in the general population, but evidence in individuals with stroke remains limited. This study examined the cross-sectional association between the Healthy Eating Index-2020 (HEI-2020) and PSD.
Methods
This study included 962 adults with a history of stroke from seven cycles of the National Health and Nutrition Examination Survey from 2005 to 2018. Depressive symptoms were assessed using the Patient Health Questionnaire-9, with a score ≥ 10 indicating probable depression. Dietary quality was evaluated using HEI-2020 and categorized into tertiles. Multivariate logistic regression, restricted cubic spline analysis, and mediation analysis were used to assess associations and the statistical indirect association of the Dietary Index for Gut Microbiota (DI-GM).
Results
After multivariate adjustment, each one-point increase in HEI-2020 score was associated with 2% lower odds of probable depression (PHQ-9-defined) (OR = 0.98). Compared with the low dietary quality group, the high dietary quality group had 59% lower odds (OR = 0.41). The dose-response relationship was nonlinear, with a significant inverse association observed only when HEI-2020 scores exceeded 57. This exploratory threshold may serve as a reference for future prospective studies but requires validation before clinical application. Furthermore, a significant interaction with race or ethnicity was identified (P for interaction = 0.033). DI-GM showed a significant indirect association (P = 0.04), but the direct and indirect components were in opposite directions, indicating an inconsistent mediation pattern. Given that DI-GM is a dietary proxy, these findings reflect statistical associations with a dietary pattern, not biological mediation. Future studies with direct microbiome measurements are needed to verify gut-brain axis involvement in PSD.
Conclusions
In this cross-sectional study, HEI-2020 was inversely associated with PSD, with nonlinear and race-specific patterns. DI-GM showed a significant but inconsistent indirect association, suggesting a suppressive rather than mediating role. Findings are associational, not causal.