Cerebral microbleeds and the risk of mortality in the general population

Presence of cerebral microbleeds indicates underlying vascular brain disease and has been implicated in lobar hemorrhages and dementia. However, it remains unknown whether microbleeds also reflect more systemic vascular burden. We investigated the association of microbleeds with all-cause and cardiovascular related mortality in the general population. We rated the brain magnetic resonance imaging scans of 3979 Rotterdam Scan Study participants to determine presence, number, and location of microbleeds. Cox proportional hazards models, adjusted for age, sex, subcohort, vascular risk factors, and other MRI markers of cerebral vascular disease, were applied to quantify the association of microbleeds with mortality. After a mean follow up of 5.2 (+/- 1.1) years, 172 (4.3 %) people had died. Presence of microbleeds, and particularly deep or infratentorial microbleeds, was significantly associated with an increased risk of all-cause mortality [sex-, age-, subcohort adjusted hazard ratio (HR) 2.27; CI 1.50-3.45], independent of vascular risk factors (HR 1.87; 95 % CI 1.20-2.92). The presence of deep or infratentorial microbleeds strongly associated with the risk of cardiovascular related mortality (HR 4.08; CI 1.78-9.39). Mortality risk increased with increasing number of microbleeds. The presence of microbleeds, particularly multiple microbleeds and those in deep or infratentorial regions, indicates an increased risk of mortality, independent of other MRI markers of cerebral vascular disease. Our data suggest that microbleeds may mark severe underlying vascular pathology associated with poorer survival.