The Complex Relationship Between Cholesterol and Brain Hemorrhage

Abstract

In this issue of Circulation , Noda et al1 report an association between low levels of low-density lipoprotein cholesterol (LDL-C) and an increase in the risk of fatal intraparenchymal intracerebral hemorrhage in a Japanese population-based cohort. The relationship between lipid levels and stroke is complex. The Prospective Studies Collaboration conducted a meta-analysis evaluating the association between blood cholesterol and vascular mortality based on data from 61 prospective cohort studies including nearly 900 000 persons free of vascular disease at baseline (11.6 million person-years at risk).2 Lower levels of usual total cholesterol were strongly associated with lower risk of fatal ischemic heart disease; every 1 mmol/L lower cholesterol was associated with a 56% reduction (hazard ratio [HR], 0.44; 95% CI, 0.42 to 0.48) in those 40 to 49 years of age, a 34% reduction (HR, 0.66; 95% CI, 0.65 to 0.68) in those 50 to 69 years of age, and a 17% reduction (HR, 0.83; 95% CI, 0.81 to 0.85) in those 70 to 89 years of age. In contrast to death resulting from ischemic heart disease, there was only a weak relationship between usual total cholesterol and death caused by stroke in those 40 to 59 years of age (HR, 0.90; 95% CI, 0.84 to 0.97 for every 1 mmol/L lower cholesterol) and no relationship for older age groups after accounting for blood pressure. An analysis combing the data for the Prospective Studies Collaboration with data from the Multiple Risk Factors Intervention Trial (MRFIT) also found that lower usual total cholesterol was associated with a lower risk of fatal stroke in those 40 to 49 years of age (HR, 0.87; 95% CI, 0.76 to 1.00 per 1 mmol/L lower total cholesterol), with similar reductions in those 50 to 59 (HR, 0.91; 95% CI, 0.85 to 0.97) and 60 …