Lipids Are Risk Factors for Ischaemic Stroke: Overview and Review

Uncertainty remains about the aetiological role of lipids in stroke. We reviewed the epidemiology in the light of new studies and have reinterpreted the evidence. A statistical overview performed on ten prospective studies examining the relationship between total cholesterol and subsequent stroke produced a pooled relative risk of 1.31 (95% confidence interval 1.11–1.54; p < 0.01) for subjects with total cholesterol levels (roughly) 220 mg/dl and above, compared with subjects with values below this level. Correction of ''regression dilution'' due to measurement error arising from only one estimation of total cholesterol increased the pooled relative risk to 2.90 (95% confidence interval 1.43–5.87). Studies using transient ischaemic attack as a surrogate model for ischaemic stroke support the role of cholesterol as a risk factor. A more detailed examination of the plasma lipoprotein fractions in a recent study suggests that the pattern of dyslipoproteinaemia associated with ischaemic heart disease – high levels of total and LDL-cholesterol, reduced levels of HDL cholesterol – applies also to ischaemic stroke. We argue that total cholesterol (and LDL- and HDL-cholesterol) is a risk factor for ischaemic stroke disease, albeit a less potent one.