William M. Feinberg Award for Excellence in Clinical Stroke
Big Pictures and Small Vessels
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Clinicians and patients tend to think of stroke as big acute brain injury, but small progressive vascular contributions to cognitive impairment and dementia (VCID) represent arguably a much greater societal burden. Dementia is certainly the preeminent public health threat of our time, estimated to affect 35.6 million individuals worldwide in 2010 and projected to double every 20 years to a staggering 115.4 million in 2050,1 including >13 million Americans.2
Abundant lines of evidence have implicated small vessel brain disease as a major contributor to this dementia tsunami. Clinical–pathological correlation in ROS-MAP (Religious Orders Study and Rush Memory and Aging Project) shows that each level of greater severity of small or large vessel disease pathology confers higher likelihood of a clinical diagnosis of Alzheimer’s disease (AD) and that these associations with vascular disease are independent of actual AD pathology.3 Similar findings are seen in clinical–radiological correlation: individuals with clinically silent brain infarcts in the Rotterdam Study have more than double the hazard of subsequent dementia.4
Realizing that most age-related dementia represents a mix of neurodegenerative and vascular pathologies5 may sound like a reason to lose hope that this tsunami can be slowed, but should be considered the opposite: more contributors mean more opportunities to intervene. The very real possibility that improved vascular health has already reduced dementia incidence is highlighted by the Framingham Heart Study finding of a steady fall in the 5-year age- and sex-adjusted cumulative hazard rate for dementia per 100 persons from 3.6 for individuals with baseline exams in the 1978 to 1983 period to 2.8 for 1986 to 1991, 2.2 for 1992 to 1998, and 2.0 for 2004 to 2008.6 Some of this decline may reflect important nonvascular factors such as improving education, but it coincides notably with sizable improvements in …