Table 4:

Prospective population-based cohort studies of white matter-lesion severity and incident stroke

Study Group	Clinical Entry Criteria	Total Number of Patients	Follow-up (y)	Definition of WM Outcome Variable	% of Incident Strokes During Follow-up by WM Outcome Variable	Cumulative Stroke Incidence	Multivariable Adjusted Relative Risk (95% CI)	Subtype of Stroke	Subtype of Ischemic Stroke
Dutch TIA Trial Group7	TIA or non-disabling ischemic stroke (Rankin ≤3)	3017	Not clearly defined	WMH vs No WMH	15% vs 8%	19% vs 10% (3 y)	1.6 (1.2–2.2)	Ischemic 90% vs 89%; hemorrhage 6% vs 9%; unknown 4% vs 2%	Large artery 47% vs 45%; lacunar 33% vs 29%; vertebrobasilar 10% vs 15%
NASCET Group5	Symptomatic carotid artery disease without WMH on entry CT	596	6.0 (median)	Development of WMH vs no WMH	36% vs 23.5%	Not defined	1.5 (1.0–2.4)	Not defined	Large artery 66% vs 73%; lacunar 29% vs 21%; cardioembolic 5% vs 6%
ARIC Group10	No history of stroke of TIA	1684	4.7 (median)	Grade ≥3 vs grade <3^*	6.5% vs 1.3%	6.8% vs 1.4% (5 y)	3.4 (1.5–7.7)	Not subdivided by WM status: ischemic 78%; hemorrhage 16%; combined 6%	Not defined
Rotterdam Scan Study Group9	No history of stroke or TIA	1077	4.2 (mean)	Third tertile grade vs first tertile grade	Not defined	Not defined	4.7 (2.0–11.2) (periventricular lesions); 3.6 (1.4–9.2) (subcortical lesions)	Not subdivided by WM status: ischemic 74%; hemorrhage 10%; unspecified 16%	Not defined
CHS Group8	No history of stroke or TIA	3293	7 (median)	Grade ≥5 vs grade ≤1^†	27.6% vs 6.0%	2.8% vs 0.6% (annual risk)	3.0 (1.9–4.7)	Ischemic (81%)	Lacunar (15%); cardioembolic (27%); atherosclerotic (5%); unknown (47%); mixed (6%)

Note.— TIA indicates transient ischemic attack; WMH, white matter hypodensity; NASCET, North American Symptomatic Carotid Endarterectomy Trial Group; ARIC, Atherosclerosis Risk in Communities Study; CHS, Cardiovascular Health Study Collaborative Research Group; CI, confidence interval.
* WM grade 3 defined as thicker continuous periventricular rim with scattered patches of subcortical WM lesions.
† Grade 1 defined as discontinuous periventricular rim or minimal “dot”of subcortical disease; grade 5 defined as mild periventricular confluence surrounding the frontal and occipital horn.