The association of depressive symptoms and dietary inflammatory index with frailty in older adults with diabetes

Older adults with diabetes exhibit heightened risks of depression and frailty, with chronic inflammation proposed as a potential mechanism. This study investigates the combined association of depressive symptoms and pro-inflammatory diets with frailty. This study utilized data from older adults with diabetes collected during the 2007–2018 cycles of the National Health and Nutrition Examination Survey (NHANES). Dietary inflammatory potential was evaluated using the Dietary Inflammatory Index (DII). Depressive symptoms were evaluated using the Patient Health Questionnaire-9. Participants were classified into six mutually exclusive groups: No depressive symptoms & Low-DII, No depressive symptoms & High-DII, Mild depressive symptoms & Low-DII, Mild depressive symptoms & High-DII, Moderate-to-severe depressive symptoms & Low-DII, and Moderate-to-severe depressive symptoms & High-DII. Frailty was defined by a modified 35-item Frailty Index. Weighted multivariable logistic regression evaluated individual/joint associations of DII and depressive symptoms with frailty. Sensitivity and subgroup analyses assessed robustness. A total of 2667 older adults with diabetes (weighted mean age 69.7 years, 53% male) were recruited. Elevated depressive symptoms score and higher DII independently increased frailty risk (adjusted OR per unit increase: depression OR = 1.16, 95% CI = 1.12–1.21; DII OR = 1.12, 95% CI = 1.02–1.23). Compared with reference group (No depressive symptoms & Low-DII), participants with Moderate-to-severe depressive symptoms & high DII exhibited the highest frailty risk (adjusted OR = 13.82, 95% CI = 7.67–24.92). The combined depressive symptoms-DII association with frailty was stronger in subgroups of males, older adults < 70, and non-Hispanic Whites. Anti-inflammatory nutritional patterns and psychological well-being may jointly associate with lower frailty risk, supporting multidimensional care models to alleviate health burdens. Not applicable.