A certain type of stroke is on the rise

A subarachnoid hemorrhage is when bleeding occurs between the membrane that covers the brain and the space between them. This bleeding is often caused by a burst blood vessel.

Stroke affects black people at a disproportionately high rate.

According to a study recently published in Neurologymedical journal of American Academy of Neurology, the incidence of one type of stroke, called subarachnoid hemorrhage, has increased in older adults and men in recent years. Such strokes also occur in black people at a disproportionately higher rate compared to people of other races and ethnicities.

A subarachnoid hemorrhage occurs when bleeding occurs in the space between the brain and the membrane that covers it, usually as a result of a ruptured blood vessel. This type of stroke can result from a ruptured aneurysm, high blood pressure, or trauma. For this study, the researchers looked only at those that were not caused by trauma.

“Non-traumatic subarachnoid hemorrhages account for 5% to 10% of all strokes in the United States and are often fatal,” said study author Fadar Oliver Otit, MD, a scientist at SUNNY Upstate University of Medicine in Syracuse, NY. “Not only did we find an increase in these strokes in recent years, but we also found that rates are disproportionately higher and increasing in black people, while rates are not increasing in people of other races and ethnicities.”

Researchers identified 39,475 patients hospitalized for nontraumatic subarachnoid hemorrhage between 2007 and 2017 after reviewing New York and Florida state hospitalization records. They then determined the annual rate of that particular form of stroke in those states, using census data, and compared those rates over time for men, women, and different age groups, races, and ethnicities.

During the 10-year trial, the researchers found that the average incidence of this type of stroke in all participants was 11 cases per 100,000 people. Women had a higher rate of 13 cases per 100,000 people, while men had a lower rate of 10 cases. Age also increased the incidence. Men age 65 and older had an average of 22 cases per 100,000, compared with 4 cases per 100,000 in middle-aged men. The incidence increased over time by an average of 0.7% per year, with middle-aged men accounting for 1.1%, older men 2.3%, older women 0.7%, while younger women decreased by 0.7%.

Looking at race and ethnicity, the researchers found that the incidence was higher in black people – an average of 15 cases per 100,000 people – compared to non-Hispanic white people – an average of 10 cases.

Incidence increased among blacks by 1.8% per year, while rates for Hispanics, Asians, and non-Hispanic whites did not change over time.

“The incidence of this type of stroke is disproportionately higher and increasing in black people, leading to a widening racial disparity in incidence,” Otit said. “Previous research has shown that black people develop high blood pressure at a younger age and are more likely to have uncontrolled high blood pressure than non-Hispanic whites, so increased efforts to control blood pressure may help lower rates. The causes also likely extend to socioeconomic factors, including structural racism. Addressing racial disparities will require multifaceted interventions targeting stroke risk factors and socioeconomic inequities.”

A limitation of the study was that the researchers were unable to distinguish between strokes caused by aneurysms and strokes caused by aneurysms, which would have provided further insight.

Reference: “Trends in the incidence of spontaneous subarachnoid hemorrhage in the United States, 2007-2017.” Christina Xia, Haydn Hoffman, Nnabuchi Anikpezi, Karan Philip, Claribel Ui, Reema Chowdhury, Karen S. Albright, Hesham Massoud, Timothy Beutler, Elena Schmidt, Graham Gould, Smith D. Patel, Emmanuel Oladele Okano, Nicholas Morris, Simant Chaturvedi, Ehimene Ani, Oluwatomi Lamikanra, Lawrence Chin, Julius G. Latorre and Fadar Oliver Otite, 26 October 2022. Neurology.
DOI: 10.1212/WNL.0000000000201340 A certain type of stroke is on the rise

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