Associations of self-management behaviors, depressive symptoms, and glycemic control on cognitive function in rural elderly with type 2 diabetes

Background: The elderly with type 2 diabetes mellitus (T2DM) are often affected by mild cognitive impairment (MCI). However, little is known about the potential mechanisms between the psychological and behavioral factors and MCI among rural Chinese elderly with T2DM. This cohort survey explored the effects of changes in self-management behaviors, depressive symptoms, and glycemic control on MCI. Methods: This study was conducted from 2019 to 2024 in the rural health clinics in China. At baseline and during follow-up in this cohort study, data on changes in self-management behaviors (the Summary of Diabetes Self-Care Activities, Δ SDSCA), depressive symptoms (the 10-item Center for Epidemiologic Studies Depression Scale, Δ CESD-10), cognitive function (the 30-item Mini-Mental State Examination, MMSE), and glycemic control were assessed. MCI was defined as MMSE scores below education-adjusted cutoffs. Hierarchical multiple regression and mediation model analysis were employed to examine the effects of these variables. Results: Among 232 participants, 37.07% had MCI at the follow-up stage. Hierarchical multiple regression analysis revealed that improved self-management behaviors (β = 0.233, P < 0.01) significantly predicted better glycemic control. In addition, improved self-management behaviors (increased Δ SDSCA score) (β = 0.220, P < 0.001), less depressive symptoms (decreased Δ CESD-10 score) (β = -0.145, P < 0.05), and better glycemic control (β = 0.143, P < 0.05) were associated with lower risks of MCI. Mediation analysis suggested that better glycemic control partially mediate the effects of improved self-management (increased Δ SDSCA score) on reducing the incidence of MCI (increasing MMSE score) (indirect effect = 0.035, 95% CI [0.006, 0.074]). Conclusions: Improving self-management behaviors may contribute to more favorable cognitive function by controlling glycemic control. Furthermore, alleviating depressive symptoms may reduce the later incidence of MCI.