Dementia and Stroke Risk Associated with Brain Artery Luminal Diameters.

Background: It is unclear whether brain artery diameters measured on conventional T2‐weighted brain MRI images relate to dementia and stroke outcomes across distinct populations. We aimed this study to evaluate the association of T2‐weighted brain artery luminal diameters with dementia and stroke in three distinct population‐based studies. Methods: Three longitudinal population‐based studies with 8420 adults >40 years old (Northern Manhattan Study [NOMAS] from the United States, and the Rotterdam Study [RS], from the Netherlands, and Three‐City, from France) with brain MRI scans obtained between 1999 and 2015. The median follow‐up time for clinical events ranged between 7 and 12.5 years. We tested our hypothesis in each cohort separately due to local data‐sharing regulations. The exposure variable was brain carotid and basilar artery luminal diameters measured on MRI axial T2‐weighted scans. Multivariable hazard ratios (HRs) and their 95% confidence intervals (CI) expressed the risk of dementia and stroke (primary outcomes) associated with the lowest (<5th) and highest (>95th) percentiles of the rank‐normalized brain artery diameters compared to a reference group defined as the diameters distributed between the 5th and 95th percentiles. Secondary outcomes included total and vascular mortality, and fatal and nonfatal cardiovascular and coronary end points. Results: Among the three cohorts (mean age ranged from 65 to 73 y, ≥57% women), 335 participants developed dementia and 331 strokes. Compared with the reference group, participants with arterial diameters >95th percentile had a higher risk of dementia (HR range 1.15‐4.50) and any stroke (HR range 1.29‐2.03). For secondary outcomes, participants with arterial diameters >95th percentile had a consistent higher risk of coronary outcomes, vascular mortality and a composite of any vascular events. The results were less supportive of a higher risk of events among participants with arterial diameters <5th percentile except for vascular mortality. Conclusions: Individuals with dilated brain arteries are at higher risk of dementia and vascular events. Our findings were consistency across distinct populations in spite of using a non‐enhanced, conventional T2‐weighted MRI sequence. Understanding the underlying physiopathology of the reported associations, particularly with dementia and stroke, might reveal novel vascular contributions to dementia [ABSTRACT FROM AUTHOR]