Specific Dimensions of Depression Have Different Associations With Cognitive Decline in Older Adults With Type 2 Diabetes

Objective: Depression is highly frequent in older adults with Type 2 Diabetes and is associated with cognitive impairment. Yet, little is known about how various depression dimensions differentially affect cognition. We investigated longitudinal associations of specific depression dimensions with cognitive decline. <p> </p> <p>Research Design and Methods: Participants (N=1002) were from the Israel Diabetes and Cognitive Decline study, 65+ years of age with Type 2 Diabetes, not demented at baseline. Participants underwent comprehensive neuropsychological battery at baseline and every 18 months thereafter including domains of Episodic Memory, Attention/Working Memory, Semantic Categorization/Language, Executive Function and Z scores of each domain were averaged and further normalized to calculate Global Cognition. Depression items from Geriatric Depression Scale- 15 items (GDS-15) was measured at each visit and subcategorized to five dimensions: Dysphoric Mood, Withdrawal Apathy-Vigor (entitled apathy), Anxiety, Hopelessness and Memory complaint. Random coefficients models examined association of depression dimensions with baseline and longitudinal cognitive functioning adjusting for socio-demographics and baseline characteristics, including cardiovascular risk factors, physical activity and use of diabetic medications. </p> <p> </p> <p>Result: In the fully adjusted model, at baseline, all dimensions of depression, except for anxiety, were associated with some aspects of cognition (p-values from .01 to <.001). Longitudinally, greater apathy scores were associated with faster decline in executive functions (p=.004), a results that withstood adjustment for multiple comparisons. Associations of other depression dimensions with cognitive decline were not significant (p>0.01).</p> <p> </p> <p>Conclusion: Apathy was associated with a faster cognitive decline in executive functions. These findings highlight the heterogeneity of depression as a clinical construct rather than a single entity and point to apathy as a specific risk factor for cognitive decline among older adults with Type 2 Diabetes. </p>