Objective
To determine if depression, cognitive impairment without dementia (CIND), and/or dementia are each independently associated with risk of ischemic stroke and to identify characteristics that could modify these associations.
Methods
This retrospective-cohort study examined a population-based sample of 7,031 Americans > 50 years old participating in the Health and Retirement Study (HRS) (1998-2008) who consented to have their interviews linked to their Medicare claims. The 8-item Center for Epidemiologic Studies Depression Scale and/or International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) depression diagnoses were used to identify baseline depression. The Modified Telephone Interview for Cognitive Status and/or ICD-9-CM dementia diagnoses were used to identify baseline CIND or dementia. Hospitalizations for ischemic stroke were identified via ICD-9-CM diagnoses.
Results
After adjusting for demographics, medical comorbidities, and health-risk behaviors, CIND alone (Odds Ratio [OR]: 1.37, 95%CI: 1.11, 1.69) and co-occurring depression and CIND (OR: 1.65, 95%CI: 1.24, 2.18) were independently associated with increased odds of ischemic stroke. Depression alone was not associated with odds of ischemic stroke (OR: 1.11, 95%CI: 0.88, 1.40) in unadjusted analyses. Neither dementia alone (OR: 1.09, 95%CI: 0.82, 1.45) nor co-occurring depression and dementia (OR: 1.25, 95%CI: 0.89, 1.76) were associated with odds of ischemic stroke after adjusting for demographics.
Conclusions
CIND as well as co-occurring depression and CIND are independently associated with increased risk of ischemic stroke. Individuals with co-occurring depression and CIND represent a high-risk group that may benefit from targeted interventions to prevent stroke.