Nutritious Partner: Association Between Educational Assortative Marriage and Healthy Eating in Chinese Older Adults

Introduction: Promoting healthy dietary patterns among older adults is a crucial strategy for mitigating health equity disparities. As a key social determinant, educational assortative marriage (EAM) profoundly shapes health behaviors in later life via interpersonal influence and shared household dynamics. Despite its importance, the specific impact of EAM patterns on the diet quality of Chinese older adults remains significantly underexplored. Methods: We utilized cross-sectional data from the 2017 to 2018 wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). A Healthy Eating Index (HEI) was constructed based on self-reported intake of 13 food groups, which were further categorized into plant-based and animal-based components. EAM was classified into homogamy, hypogamy, and hypergamy. Ordinary least squares (OLS) regression models were estimated, and the entropy balancing method was applied to adjust for covariate imbalance. Results: Compared to homogamy marriages, hypogamy marriages were significantly associated with lower HEI scores (adjusted and balanced β = −1.44, p < 0.01). Conversely, hypergamy marriages were significantly associated with higher HEI scores (adjusted and balanced β = 1.38, p < 0.01). In extended analysis, the association between EAM patterns and HEI persists predominantly among couples without higher education. Gender heterogeneity analysis revealed that the association between EAM and HEI was more pronounced among men than women. Conclusion: This study demonstrates that EAM is a significant social determinant of diet quality among Chinese older adults. Public health interventions promoting healthy aging should consider the educational dynamics within couples, targeting nutritionally vulnerable marital subgroups with tailored strategies.