Mechanism of increased risk unclear
The researchers do not yet know how low triglyceride and LDL cholesterol levels increase the risk of hemorrhagic stroke. One hypothesis is that low cholesterol promotes necrosis of the arterial medial layer’s smooth muscle cells. This impaired endothelium might be more susceptible to microaneurysms, which are common in patients with ICH, said the researchers.
The prospective design and the large sample size were two of the study’s strengths, but the study had important weaknesses as well, the researchers wrote. For example, few women were premenopausal at baseline, so the investigators could not evaluate whether menopausal status modifies the association between lipid levels and risk of hemorrhagic stroke. In addition, lipid levels were measured only at baseline, which prevented an analysis of whether change in lipid levels over time modifies the risk of hemorrhagic stroke.
Dr. Rist reported receiving a grant from the National Institutes of Health.
SOURCE: Rist PM et al. Neurology. 2019 April 10. doi: 10.1212/WNL.0000000000007454.