Body insulin resistance is associated with increased stroke risk, but the effect has not been adequately examined separately in White and Black populations. Therefore, Dr. George Howard, professor in the department of biostatistics at the University of Alabama at Birmingham—along with department colleague Dr. Suzanne E. Judd, associate professor, as well as Dr. Virginia J. Howard, professor in the department of epidemiology—assessed the association of baseline insulin resistance with risk of cerebral infarction (CI) and intracerebral hemorrhage (ICH) in 12,366 White and 6,782 Black participants (recruited between 2003 and 2007 and followed for an average of 5.7 years) from the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort.

[Photo: Dr. George Howard]

In this study, insulin resistance was measured with the homeostasis model assessment-insulin resistance. There were 364 incident CI and 41 incident ICH events. The risk for CI increased with the log of insulin resistance in whites but was largely attenuated by adjustment for stroke risk factors; there was no association in Blacks. After adjustment for demographic factors and risk factors, the researchers found that there was a significant difference by race in the association of insulin resistance with risk of ICH, with a decrease in the risk of ICH in Whites but a nonsignificant increase in Blacks.

The team concluded that these data support the growing evidence that insulin resistance may play a more important role in stroke risk among White than Black individuals and suggest a potentially discordant relationship of insulin resistance on CI and ICH among whites. “Racial Differences in the Association of Insulin Resistance With Stroke Risk: The REasons for Geographic And Racial Differences in Stroke (REGARDS) Study” was published in June 2014 in the journal Stroke.

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