Background: Vascular localization of symptomatic large artery atherosclerotic (LAA) stroke differs for unknown reasons by race-ethnicity. The metabolic syndrome (MetSD) is associated with higher atherosclerotic stroke risk and comprises abnormal risk factors that can vary by race. Thus, we investigated whether MetSD may contribute to race-ethnic differences in LAA stroke by examining the association of MetSD with symptomatic intra- and extracranial atherosclerosis among a diverse race-ethnic group.
Method: We analyzed data prospectively collected over a 4-year period on subjects with ischemic stroke/TIA. Independent vascular risk factor associations with intracranial and extracranial LAA vs. non-LAA mechanism were evaluated in two groups stratified by race-ethnicity; whites and non-whites (Hispanics, African-American, and Asian-American).
Results: 1167 patients met study criteria. Intracranial LAA was more prevalent in non-whites vs. whites (20.4% vs. 9.6%, P<0.001), while extracranial LAA had a more frequent point value in whites compared to non-whites (10.7% vs. 7.5%, P=0.267). The presence of MetSD was more prevalent in both intracranial and extracranial LAA group than in non-LAA group: no significant differences were observed in the prevalence of MetSD between intra vs. extracranial LAA or whites vs. non-whites. However, with increasing numbers of abnormal metabolic components, whites were more likely to have experienced extracranial LAA, whereas non-whites were more likely to have experienced intracranial LAA. After adjusting for covariates, MetSD was associated with extracranial LAA in whites (OR, 1.98; 95% CI, 1.13-3.45), while there was a tendency that intracranial LAA was associated with MetSD in non-whites (OR, 1.80; 95% CI, 0.97-3.32). No association was found between MetSD and extracranial LAA in non-whites and between this syndrome with intracranial LAA in whites.
Conclusions: Our results showed that the impact of MetSD on the distribution of cervicocephalic atherosclerosis differed by race-ethnicity. This finding may in part explain the well-known differences in race-ethnic predilection to intracranial or extracranial atherosclerosis.