Cross-sectional association between a CLHLS-based diet quality score and screening-defined elevated depressive symptoms among Chinese older adults.

BACKGROUND

Depressive symptoms are common in later life and may be related to dietary behaviours. However, dietary habits and depressive symptoms may influence each other, and cross-sectional data cannot establish temporal direction. This study examined the cross-sectional association between a Chinese Longitudinal Healthy Longevity Study (CLHLS)-based diet quality score and screening-defined elevated depressive symptoms among Chinese older adults.

METHODS

This cross-sectional study used data from the 2018 CLHLS. Dietary behaviour was assessed using self-reported intake frequency of 13 food groups, with items coded so that higher values indicated higher intake frequency. A CLHLS-based diet quality score was then constructed. Elevated depressive symptoms were assessed using the CESD-10. Multivariable logistic regression was used to examine the association between diet quality and elevated depressive symptoms. False discovery rate correction was applied in exploratory food-group analyses. Sensitivity analyses included multiple imputation with 20 datasets and a modified CESD-10 score excluding the sleep-quality item.

RESULTS

Among 15,874 participants in the 2018 CLHLS, 12,069 adults aged 60 years or older had complete dietary and depressive symptom data. In the fully adjusted complete-case model (n = 9,086), each five-point increase in the CLHLS-based diet quality score was associated with lower odds of elevated depressive symptoms (OR = 0.877, 95% CI: 0.844-0.912, p < 0.001). Although statistically significant, the association was modest in magnitude, and explanatory power was limited. The multiple-imputation analysis yielded a similar estimate (pooled OR = 0.890, 95% CI: 0.860-0.922, p < 0.001). The association also remained when depressive symptoms were analysed using the modified CESD-10 score. In exploratory food-group analyses, higher reported intake frequencies of fruit and vegetables were associated with lower odds of elevated depressive symptoms after adjustment.

CONCLUSION

The CLHLS-based diet quality score was weakly associated with screening-defined elevated depressive symptoms. These findings should be interpreted as descriptive and hypothesis-generating, rather than causal or sufficient to support clinical or public health dietary recommendations. Longitudinal studies using validated dietary assessment tools are needed.