Do depressive symptoms link chronic diseases to cognition among older adults? Evidence from the Health and Retirement Study in the United States.

BACKGROUND: Few studies have assessed psychological pathways that connect the association between non-psychotropic chronic disease and cognition. We assessed the extent to which the association between the two was mediated by depressive symptoms in older adults.

METHODS: Data came from waves 10-13 (2010-2016) of the Health and Retirement Study in the United States (7,651 men and 10,248 women). Multilevel path analysis, allowing for random intercepts and slopes, was employed to estimate the extent to which depressive symptoms mediated the total effect of a chronic disease on cognition.

RESULTS: We found that the presence of stroke, high blood pressure, diabetes, heart problems, and comorbidity, in both men and women, and lung disease in women, was associated with lower levels of cognition. The total effects of chronic diseases on cognition were partially mediated through depressive symptoms. Depressive symptoms mediated approximately 19%-39% and 23%-54% of the total effects of chronic diseases on cognition in men and women, respectively.

LIMITATIONS: We relied on self-reported diagnoses of diseases and depressive symptoms. Our use of a multilevel path analysis with random slopes precluded the inclusion of binary/categorical dependent variables, and the estimation of standardized beta values.

CONCLUSIONS: To understand the cognitive challenges that chronically ill older adults face, practitioners and policymakers should consider not just the direct symptoms related to chronic diseases, but also the often overlooked psychological conditions faced by older adults.