Association between depressive symptoms, metabolic risk factors, and cognitive function: cross-sectional results from a community study in Quebec, Canada

Abstract

Objective To investigate the cross-sectional association between depressive symptoms and metabolic risk factors with cognitive function in a middle-aged population. Methods A stratified subsample of the CARTaGENE (CaG) cohort (n = 1991) was used to compare cognitive function outcomes between groups. The stratification was based on the presence of depressive symptoms and metabolic dysregulation (MetD): the presence of a) neither condition (reference group); b) MetD only; c) depressive symptoms only; and d) both depressive symptoms and MetD. Individuals with type 2 diabetes were excluded. Three cognitive domains were assessed: processing speed, episodic memory, and executive function. An overall cognitive function score, standardized for age and education, was computed. Poor cognitive function was defined as the lower quartile of the overall cognitive function distribution. Linear and logistic regression analyses were conducted. Results The poorest cognitive performance was observed in the group with both depressive symptoms and MetD, followed by the group with depressive symptoms only, then the group with MetD only and the reference group. Mean (SD) overall cognition scores for the four groups were −0.25 (1.13), −0.13 (1.05), 0.11 (0.90), and 0.15 (0.93), respectively. Linear regression analyses suggested a linear increase in cognitive function across groups. In the logistic regression analyses, the highest risk of poor cognitive function was observed in the comorbid (depressive symptoms and MetD) group (adjusted OR = 1.99, 95% CI 1.46, 2.71). Conclusion Comorbidity of depressive symptoms and MetD was associated with reduced cognitive performance in middle-aged adults without diabetes. KEY POINTS Poor cognitive function is a major public health concern and can be potentially prevented by targeting its modifiable risk factors. Metabolic dysregulation and depression have both been independently associated with poor cognitive function. Comorbidity of metabolic dysregulation and depressive symptoms is associated with an increased risk of poor cognitive function in middle-aged individuals. Future health interventions might benefit by screening for comorbidity in patients with poor cognitive function and by targeting depression and metabolic dysregulation together.