Lipid levels and the risk of ischemic stroke in women

OBJECTIVE: To evaluate the association between total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol to HDL-C ratio, and non-HDL-C with the risk of ischemic stroke in a large cohort of apparently healthy women. METHODS: Prospective cohort study among 27,937 US women aged > or =45 years participating in the Women's Health Study who provided baseline blood samples. Stroke occurrence was self-reported and confirmed by medical record review. We categorized plasma lipid measurements into quintiles. We used Cox proportional hazards models to evaluate the association between lipids and risk of ischemic stroke. RESULTS: During 11 years of follow-up, 282 ischemic strokes occurred. All lipid levels were strongly associated with increased risk of ischemic stroke in age-adjusted models. The association attenuated particularly for HDL-C after adjustment for potential confounders. For the comparison of the highest to the lowest quintile, the multivariable-adjusted hazard ratios (95% CI; p for trend across mean quintile values) of ischemic stroke were 2.27 (1.43, 3.60; p(trend) < 0.001) for total cholesterol; 1.74 (1.14, 2.66; p(trend) = 0.003) for LDL-C; 0.78 (0.52, 1.17; p(trend) = 0.27) for HDL-C; 1.65 (1.06, 2.58; p(trend) = 0.02) for the total cholesterol to HDL-C ratio; and 2.45 (1.54, 3.91; p(trend) < 0.001) for non-HDL-C. CONCLUSIONS: In this large cohort of apparently healthy women, total cholesterol, low-density lipoprotein cholesterol, the total cholesterol to high-density lipoprotein cholesterol ratio, and non-high-density lipoprotein cholesterol were significantly associated with increased risk of ischemic stroke.