Study Finds Higher Prevalence of Intracranial Atherosclerosis in Black Men

Black men have the highest prevalence of intracranial atherosclerotic disease (ICAD) and the highest frequency of multiple plaques, according to a new study in JAMA Cardiology.

The study analyzed the racial differences in the prevalence and risk of ICAD. While it is known that strokes are more prevalent in black individuals, it was still unclear if ICAD is also more prevalent.

“Racial differences in intracranial atherosclerotic disease prevalence may help to explain stroke rates in the United States, and differences in intracranial atherosclerotic disease risk factors could offer insight into preventative risk-factor management strategies,” wrote the authors.

The study included 1752 black and white participants from the Atherosclerosis Risk in Communities Study. The baseline visit took place between 1987 and 1989, and patients were aged 45 to 64 years. There were 4 subsequent visits, and on the fifth visit patients were aged 67 to 90 years. Each patient underwent 3-dimensional intracranial vessel wall magnetic resonance imaging between October 18, 2011, and December 30, 2013.

Cardiovascular risks were measured from the first and fifth visits were recorded. The risk factors included: smoking history; systolic and diastolic blood pressures; antihypertensive medication use; plasma low-density lipoprotein cholesterol level; plasma high-density lipoprotein cholesterol level; plasma triglyceride level; cholesterol-lowering medication use; fasting and non-fasting glucose levels; antidiabetic medication use; history of coronary disease; and history of stroke.

The authors of the study found that the black participants were younger than the white participants and were more likely to have hypertension and diabetes, but less likely to have hyperlipidemia at both midlife and late-life visits. Both black and white groups had a higher prevalence of cardiovascular disease risk factors in late life compared to midlife.

Results showed that 637 (36.4%) of participants had ICAD with at least 1 intracranial plaque.

Black men had both the highest ICAD prevalence (50.9%) and frequency of multiple plaques (22.4%) at visit 5. The prevalence of ICAD reached 50% in black men before 68 years, white men by 84 years, and white women by 88 years. Black women did not have a 50% prevalence even at 90 years.

For cardiovascular disease risk factors, midlife hypertension was associated with a 29% increased prevalence of ICAD and hyperlipidemia was associated with an 18% increased prevalence of ICAD by visit 5 for both races. Midlife smoking and diabetes were associated with a 102% and 57%, respectively, increased prevalence of ICAD by visit 5 for black participants.

“Our findings have clinical implications, as they might help to 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,” concluded the authors.