Association of cholesterol with stroke risk varies in stroke subtypes and patient subgroups

Objective: To perform a health maintenance organization-based case-control study to evaluate the association of total and high density lipoprotein (HDL) cholesterol with the risk of stroke subtypes and in patient subgroups. Methods: Cases had a confirmed incident ischemic stroke (n = 1,242) or hemorrhagic stroke (n = 313). Controls (n = 6,455) were identified in a companion myocardial infarction study. Risk of stroke was modeled using logistic regression. Results: The highest total cholesterol quintile was associated with an increased risk of ischemic stroke compared to the lowest quintile (OR = 1.6, 95% CI 1.3 to 2.0) with the strongest subtype associations for atherosclerotic stroke (OR = 3.2) and lacunar stroke (OR = 2.4). The highest HDL cholesterol quintile was associated with a decreased risk of ischemic stroke compared to the lowest quintile (OR = 0.8, CI 0.6 to 1.0). Subgroup analyses suggested that the total cholesterol association was more important for patients <66 years of age and those with HDL <50 mg/dL; the HDL association was more important for patients without diabetes or atrial fibrillation. The second through fourth total cholesterol quintiles were associated with a decreased risk of hemorrhagic stroke compared to the lowest quintile (OR = 0.7, CI 0.5 to 1.0). Conclusions: Higher total and lower HDL cholesterol levels were associated with increased risk of ischemic stroke, especially certain stroke subtypes and patient subgroups. The lowest levels of total cholesterol were associated with an increased risk of all hemorrhagic strokes.