Cerebral Microbleeds are Associated With an Increased Risk of Stroke: The Rotterdam Study
Background—Cerebral microbleeds are highly prevalent in people with clinically manifest cerebrovascular disease, and have been shown to increase the risk of stroke recurrence. Microbleeds are also frequently found in healthy elderly, a population in which the clinical implication of microbleeds is unknown.
Methods and Results—In the population-based Rotterdam Study, presence, number, and location of microbleeds were assessed at baseline on brain MRI of 4,759 participants aged ≥45 years. Participants were followed for incident stroke throughout the study period (2005 until 2013). We used Cox proportional hazards to investigate if people with microbleeds were at increased risk of stroke compared to those without microbleeds, adjusting for demographic, genetic, and cardiovascular risk, and cerebrovascular imaging markers. Microbleed prevalence was 18.7% (median count 1 [1-111]). During mean follow-up of 4.9 years (SD 1.6) 93 strokes occurred (72 ischemic, 11 hemorrhagic, and 10 unspecified). Microbleed presence was associated with an increased risk of all strokes (HR 1.93, 95% CI 1.25-2.99). The risk increased with greater microbleed count. Compared to those without microbleeds, participants with microbleeds in locations suggestive of CAA (lobar with or without cerebellar microbleeds) were at increased risk of intracerebral hemorrhage (HR 5.27, 95% CI 1.38-20.23). Microbleeds at other locations were associated with an increased risk of both ischemic stroke and intracerebral hemorrhage.
Conclusions—Microbleeds on MRI are associated with an increased risk of stroke in the general population. Our results strengthen the notion that microbleeds mark progression of cerebrovascular pathology and represent a precursor of stroke.
- Received February 27, 2015.
- Revision received June 1, 2015.
- Accepted June 4, 2015.