BALTIMORE, MD – Intracranial atherosclerotic disease (ICAD), a major contributor to ischemic stroke, is more common in black men than black women as well as white men and women, which may explain their higher risk of stroke, according to new data from the Atherosclerosis Risk in Communities (ARIC) study[1].
The “main message” is that ICAD is “highly prevalent in older adults, especially black men, and should be an important consideration when evaluating reasons for stroke,” Dr Bruce A Wasserman (Johns Hopkins University School of Medicine, Baltimore, MA) told theheart.org | Medscape Cardiology.
The study was published online November 1 in JAMA Cardiology.
Researchers assessed racial differences in ICAD prevalence and risk factors associated with its development in 1752 adults in the ARIC study who underwent 3D intracranial vessel wall magnetic resonance imaging (MRI). Mean age of participants was 77.6 years, 58.4% were women, and 29.6% were black.
The prevalence of ICAD was highest in black men compared with black women, white men, and white women (50.9% vs 35.9% vs 35.5% vs 30.2%; P<0.001). Black men also had the highest frequency of multiple plaques (22.4% vs 12.1% vs 10.7% vs 8.7%; P<0.01).
These findings “might help explain the increased stroke risk secondary to ICAD in black men in the United States, as a consequence of their higher prevalence of plaques or their higher frequency of multiple plaques,” the authors write.
“To our knowledge, racial differences in ICAD prevalence have not been previously reported in general population studies,” they add.
“Although there is no precedent for estimating intracranial atherosclerotic plaque prevalence in US communities, its prevalence was higher than we had expected,” Wasserman told theheart.org | Medscape Cardiology.
He said an important reason for this was the large number of nonstenotic plaques detected using 3D vessel wall MRI, “a new technique that identifies plaque without relying on luminal narrowing. In fact, nearly 11% of participants with intracranial plaques had nonstenotic lesions and would not have been identified by angiographic studies,” he noted.
Wasserman and a coauthor have a patent for the MRI technique used in the study.
ICAD prevalence increased with age, reaching 50% before age 68 years in black men and before age 84 and 88 years in white men and white women, respectively. ICAD prevalence remained below 50% in black women.
As for ICAD risk factors, midlife smoking and diabetes were strongly associated with late-life ICAD in black but not white individuals, whereas midlife hypertension and hyperlipidemia were associated with late-life ICAD in both, the researchers report. Midlife hypertension was also associated with larger plaques.
“These associations were observed irrespective of late-life risk status and highlight the importance of early risk-factor management,” the authors conclude.
The study was supported by grants from the National Institutes of Health.
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