Background and Purpose - Intracranial atherosclerotic stenosis (ICAS) is a common cause of stroke, but little is known about its epidemiology. We studied the prevalence of ICAS and its association with vascular risk factors using high-resolution magnetic resonance angiography in a US cardiovascular cohort. Methods - The Atherosclerosis Risk in Communities (ARIC) study recruited participants from 4 US communities from 1987 to 1989. Using stratified sampling, we selected 1980 participants from visit 5 (2011-2013) for high-resolution 3T-magnetic resonance angiography. All images were analyzed in a centralized laboratory, and ICAS was graded as: no stenosis, <50% stenosis, 50% to 69% stenosis, 70% to 99% stenosis, and complete occlusion. We calculated per-vessel and per-person prevalence of ICAS (weighted for n=6538 visit 5 participants) and also estimated the US prevalence. We used multivariable logistic regression to identify variables independently associated with ICAS. Results - Subjects who had an adequate magnetic resonance angiography (n=1765) were aged 67 to 90 years, 41% were men, 70% were white, and 29% were black. ICAS was prevalent in 31% of participants and 9% had ICAS ≥50%. Estimated US prevalence of ICAS ≥50% for 65 to 90 years old was 8% for whites and 12% for blacks. Older age, black race, higher systolic blood pressure, and higher low-density lipoprotein cholesterol levels were associated with increased odds of ICAS, whereas higher levels of high-density lipoprotein cholesterol and use of cholesterol-lowering medications were associated with decreased odds of ICAS. Body mass index and smoking were not associated with ICAS. Conclusions - The prevalence of ICAS in older adults is high, and it could be a target for primary prevention of stroke and dementia in this population.
Bibliographical noteFunding Information:
Research reported in this publication was supported by National Heart, Lung, and Blood Institute of the National Institutes of Health under award number R01HL105626 and R01HL105930. The ARIC study is carried out as a collaborative study supported by National Heart, Lung, and Blood Institute contracts (HHSN268201100005C, HHSN268201100006C, HHSN268201100007C, HHSN268201100008C, HHSN268201100 009C, HHSN268201100010C, HHSN268201100011C, and HHSN 268201100012C). Neurocognitive data are collected by U01 HL096812, HL096814, HL096899, HL096902, and HL096917 from the National Heart, Lung, and Blood Institute (NHLBI) and the National Institute of Neurological Disorders and Stroke, and with previous brain MRI examinations funded by R01-HL70825 from the NHLBI. We thank the staff and participants of the ARIC study for their important contributions.
© 2016 American Heart Association, Inc.
- intracranial atherosclerosis stenosis
- intracranial stenosis
- magnetic resonance angiography