Lipids and stroke: neglect of a useful preventive measure?

The epidemiological studies linking lipid variables and stroke are reviewed. These studies indicate that serum total cholesterol (TC) levels are associated positively with thrombotic and negatively with haemorrhagic strokes. Relationships for other lipid fractions are not as clearly defined. The results of trials with lipid lowering drugs suggest that only statins effectively reduce the incidence of stroke. Differences between trial results may be due to variation in the extent of reduction of TC levels. Possible underlying mechanisms for benefit and the apparent superiority of statins are also discussed. The reduction in the risk of thrombotic stroke with statins is most evident through meta-analyses (p < 0.001) and less impressive in individual trials (p < 0.03). This difference is largely attributable to the small number of events in trials primarily aimed at evaluating ischaemic heart disease (IHD) reduction. This also means that benefit may be limited to those with established IHD. IHD and thrombotic stroke share common risk factors and patients with one condition are at high risk of developing the other. Therefore, one additional reason for using statins in these patients is that these drugs can effectively prevent IHD-related events including deaths.