Mid- and late-life depression increases risk of Alzheimer's disease and related dementias in veterans.

INTRODUCTION

Using 20-year data from the Veterans Health Administration's electronic health record, we explored associations between mid- and late-life depression with incident Alzheimer's disease and related dementias (ADRD).

METHODS

Participants included Veterans with (n = 272,739) and without (n = 435,965) depression matched on sociodemographic and healthcare utilization factors. International Classification of Diseases codes were used to define medical conditions. We performed a time-to-event analysis using Fine-Gray models with death as a competing event.

RESULTS

Depression was associated with ADRD (hazard ratio [HR] = 1.36; 95% confidence interval [CI] = 1.35-1.38), with higher risk for mid-life depression (age at index date <60: HR = 2.56; 95% CI = 2.44-2.69) compared to late-life depression (age ≥60: HR = 1.70; 95% CI = 1.67-1.72). This association persisted regardless of traumatic brain injury (TBI) and posttraumatic stress disorder status, but was especially strong for those with TBI prior to depression diagnosis.

DISCUSSION: Findings emphasize the need to screen for cognitive changes in Veterans diagnosed with depression, especially those with mid-life depression.