REGARDS study shows persistence of racial disparities in stroke incidence, mortality

Jun 3 2016

Blacks between the ages of 45 and 54 die of strokes at a rate that is three times greater than their white counterparts, according to the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, which looked at stroke incidence and mortality of nearly 30,000 participants over the age of 45 from an ethnically and demographically diverse sample of the U.S. population. The findings suggest that the higher risk of death from strokes in blacks is due mostly to the higher incidence in this population, and not to worse outcomes following stroke.

The REGARDS study was funded by the National Institutes of Health's National Institute of Neurological Disorders and Stroke (NINDS) and the results appear in the journal Stroke.

There has been a decline of almost 70 percent in stroke mortality rates overall in the past 50 years, making stroke the fifth leading cause of death in the United States. The reduction is attributed to improved stroke prevention due largely to better control of stroke risk factors including hypertension, diabetes, smoking cessation, and advances in post-stroke care.

However, despite the national trends showing declining stroke incidence and mortality, data from the REGARDS study confirm persistence of disparities between blacks and whites in the occurrence of stroke and mortality due to stroke. The difference in stroke incidence is believed to be due in part to differences in the prevalence of such potent risk factors as hypertension and diabetes, which are more common in blacks. However, the magnitude of the disparity in stroke mortality diminishes as the population ages, with no difference in the stroke mortality rate for those age 85 and older.

The study authors say that the key to reducing the disparity in stroke incidence and mortality is increased efforts in stroke prevention, particularly control of high blood pressure and diabetes, which affect blacks disproportionately.

"The prevalence of hypertension is higher in blacks, but its impact is even greater in the black population. An increase of 10mmHg in blood pressure is associated with an 8 percent increase in stroke risk among whites but a 24 percent increase in stroke risk in blacks," said Dr. Walter Koroshetz, director of NINDS.

Earlier this year, the NINDS launched a stroke prevention campaign called Mind Your Risks, designed to educate people aged 45-65 about the link between uncontrolled high blood pressure and the risk of developing dementia later in life. The campaign messaging launched in the Stroke Belt, an area of the southeastern U.S. where stroke incidence is high and REGARDS has focused its efforts.

"This study shows that improved risk factor prevention and management is critical if we are going to reduce the apparent increased risk of stroke and stroke mortality in blacks," said Claudia Moy, Ph.D., acting director of the Office of Clinical Research at NINDS, and one of the study authors.