Inflammatory cytokines and ischemic stroke risk: The REGARDS cohort

Area of Science:

• Cardiovascular Science
• Immunology
• Epidemiology

Background:

• Stroke incidence disproportionately affects the Black population.
• Inflammatory markers, such as interleukins, are implicated in cardiovascular disease pathogenesis.
• Understanding the role of specific cytokines in racial disparities is crucial for targeted interventions.

Purpose of the Study:

• To investigate the association between circulating interleukin-6 (IL-6), IL-8, and IL-10 levels and incident ischemic stroke risk.
• To determine if these cytokines mediate the observed racial disparity in stroke incidence between Black and White individuals.

Main Methods:

• A case-cohort study design was employed within the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study.
• Baseline IL-6, IL-8, and IL-10 concentrations were measured in a cohort of 30,237 Black and White adults (≥45 years).
• Incident stroke cases (n=557) and a subcohort (n=951) were analyzed over a 5.4-year follow-up period.

Main Results:

• Elevated IL-6 levels were significantly associated with incident stroke risk (HR for highest vs. lowest quartile: 2.4) and remained significant after adjusting for risk factors (HR: 2.0).
• IL-8 and IL-10 showed weaker associations with stroke risk.
• IL-6 mediated the racial disparity in stroke risk, primarily through its association with inflammatory risk factors.

Conclusions:

• Interleukin-6 is a significant independent predictor of incident ischemic stroke in a biracial population.
• IL-6 plays a mediating role in the racial disparity of stroke incidence, linked to inflammatory pathways of risk factors.
• Further research into the clinical utility of IL-6 for stroke risk assessment is warranted.