There is no evidence for an association between cerebral β-amyloid deposition, a marker of Alzheimer disease, and intracranial atherosclerotic plaque or stenosis, according to study results published in JAMA Neurology.
Although previous studies have shown that intracranial atherosclerotic disease (ICAD) is a significant risk factor for stroke and may increase the risk for all-cause dementia, limited data are available on the association between ICAD in adults without dementia and cerebral β-amyloid deposition.
The cross-sectional study included data on dementia-free adults aged 70-90 years from the Atherosclerosis Risk in Communities-Positron Emission Tomography (ARIC-PET) study that completed florbetapir PET scans and magnetic resonance imaging high-resolution vessel wall imaging. The main outcome was the global cortical standardized uptake value ratio (SUVR), as a scan was considered positive for β-amyloid if the global cortical SUVR was >1.2 on florbetapir PET.
The study cohort included 300 patients (mean age 76 years, 56% women) with available imaging data, of whom 105 participants (35%) had evidence for ICAD of any vessel. Mean SUVR was higher in participants with intracranial plaques compared with participants without plaques (1.34±0.29 vs 1.27±0.23, respectively; P =.03). In adjusted models, there was no statistically significant association between the presence of any plaque (adjusted odds ratio [OR] 1.20, 95% CI, 0.69-2.07), number of plaques (adjusted OR 1.10, 95% CI, 0.96-1.26), or plaque location (anterior circulation, adjusted OR 1.15, 95% CI, 0.61-2.16; posterior circulation, adjusted OR 1.27, 95% CI, 0.69-2.36) with elevated SUVR.
Similarly, there was no significant association between any measurable stenosis (adjusted OR 1.27, 95% CI, 0.71-2.27), a stenosis of >50% (adjusted OR 2.33, 95% CI, 0.82-6.60), or a stenosis of >70% (adjusted OR 2.35, 95% CI, 0.19-29.48) with elevated brain β-amyloid.
The study had several limitations, according to the researchers, including the cross-sectional nature, single measurement of β-amyloid deposition, exclusion of patients with dementia, and inability to fully adjust for potential confounders.
“We found no evidence of an association between plaque presence and global cerebral β-amyloid in individuals without dementia broadly,” concluded the researchers.
Gottesman RF, Mosley TH, Knopman DS, et al. Association of intracranial atherosclerotic disease with brain β-amyloid deposition: secondary analysis of the ARIC study [published online ahead of print, 2019 Dec 20]. JAMA Neurol. doi: 10.1001/jamaneurol.2019.4339