Cognitive reserve, depression and anxiety in older outpatients with type 2 diabetes: a case–control study

Background Population ageing and the growing burden of type 2 diabetes mellitus (T2DM) raise concern about late-life brain and mental health. Cognitive reserve (CR)—shaped by education, occupational complexity and leisure activities—may modulate the impact of T2DM on cognition, depression and anxiety, yet evidence in geriatric outpatients is limited. Aim: To compare CR, global cognition, depression and anxiety in older outpatients with and without T2DM, and to examine, within T2DM, the associations between CR and cognitive/affective outcomes. Methods Single-centre, cross-sectional case–control study of 89 outpatients aged ≥ 65 years (43 T2DM; 46 non-diabetic controls) from family medicine and endocrinology clinics. CR was assessed with the Cognitive Reserve Index questionnaire (CRIq; education, working activity, leisure; CRI total). Global cognition, depressive symptoms and anxiety were measured with the Standardized Mini-Mental State Examination Turkish validated version (SMMSE-TR) the 15-item Geriatric Depression Scale (GDS-15) and the Beck Anxiety Inventory (BAI). Between-group comparisons used non-parametric tests; within T2DM, associations were analysed with Spearman’s rho. Results Groups were similar in age, but the T2DM group had lower educational attainment and higher HbA1c. Compared with controls, T2DM patients showed lower CR in education and leisure domains and in CRI total; working activity did not differ. MMSE-TR and GDS-15 were comparable, whereas anxiety was higher in controls. Within T2DM, higher CR—particularly education and CRI total—correlated with better MMSE-TR and lower GDS-15 and BAI scores. Conclusions Older outpatients with T2DM exhibit reduced CR despite modest differences in global cognition. Brief, CR-oriented questions may help identify higher-risk patients and inform person-centred, multidomain strategies in geriatric diabetes care.