Cholesterol and the risk of ischemic stroke

Background and Purpose-Large epidemiological studies have not established cholesterol levels as a risk factor for ischemic stroke, but recent clinical trials have demonstrated a reduction in the ischemic stroke rate for patients taking HMG-CoA reductase inhibitors ("statins"). The goal of this study was to evaluate whether total cholesterol (TC), high-density lipoprotein (HDL), triglycerides, and the TC: HDL ratio are risk factors for ischemic stroke in apparently healthy men enrolled in the Physicians' Health Study. Methods-We used a nested case-control study design and matched 296 ischemic stroke cases with an equal number of controls on age, tobacco use, and follow-up time. At baseline, TC, HDL, and triglyceride levels were measured. We calculated odds ratios (ORs) and their 95% confidence intervals (CIs) using conditional logistic regression, adjusting for major risk factors for ischemic stroke. Results-Compared with the reference lowest quartile, the highest quartile for TC had an adjusted OR of 1.56 (95% CI, 0.84 to 2.92), the highest quartile of HDL had an adjusted OR of 0.75 (95% CI, 0.43 to 1.30), and the highest quartile of triglycerides had an adjusted OR of 1.07 (95% CI, 0.63 to 1.82). Although the highest quartile of the TC: HDL ratio had an adjusted OR of 1.62 (95% CI, 0.93 to 2.82), the risk of ischemic stroke was not a linear relationship. Conclusions-After adjustment, TC, HDL, and triglycerides were not significantly associated with ischemic stroke risk, and for the TC: HDL ratio, a suggestion of increased risk of ischemic stroke was limited to those with the highest levels.