Association between atherogenic index of plasma and depression in patients with type 2 diabetes mellitus

Depression is a major global public health issue and is particularly prevalent but often underrecognized among patients with type 2 diabetes mellitus (T2DM). Metabolic dysregulation has been closely linked to depressive symptoms, and the atherogenic index of plasma (AIP), a marker of dyslipidemia, may be associated with depressive symptoms. However, evidence regarding this association in T2DM populations remains limited. This study aimed to investigate the association between AIP and the risk of depressive symptoms in patients with T2DM using data from the National Health and Nutrition Examination Survey 2011 to 2016. Data were obtained from National Health and Nutrition Examination Survey 2011 to 2016 and included participants with T2DM. AIP was the primary exposure, and clinically significant depressive symptoms were assessed using the Patient Health Questionnaire-9. Multivariable logistic regression was used to evaluate the association between AIP and depressive symptoms. Smooth curve fitting was applied to examine potential nonlinearity, and receiver operating characteristic curve analysis was performed to assess the discriminative ability of AIP. Subgroup and interaction analyses were conducted to test the robustness of the association. A total of 1439 patients with T2DM were included, of whom 180 (12.51%) had clinically significant depressive symptoms. Higher AIP was associated with approximately 2-fold higher odds of depressive symptoms after adjustment for covariates in the adjust II model (odds ratio = 2.0, 95% confidence interval: 1.1–3.6, P  = .021). Receiver operating characteristic analysis showed statistically significant but limited discriminative ability of AIP for depressive symptoms, with an area under the curve of 0.5781 (95% confidence interval: 0.5341–0.6221). Subgroup analyses showed consistent associations across sex, age, education level, smoking status, and lipid levels, with no significant interactions ( P for interaction >.05). Smooth curve fitting showed no evidence of nonlinearity, suggesting a linear positive association between AIP and depressive symptoms ( P for nonlinearity = .213). In patients with T2DM, higher AIP levels were significantly associated with increased risk of depressive symptoms. AIP may serve as a supplementary indicator for assessing the risk of depressive symptoms in this population.