Cerebral microbleeds in the population based AGES-Reykjavik study: prevalence and location

Background and purpose: Incidental foci of signal loss suggestive of cerebral microbleeds (CMBs) are frequent findings on gradient echo T2* weighted MRI (T2* MRI) of patients with haemorrhagic or ischaemic stroke. There are few prevalence data on older populations. This paper reports on the prevalence and location of CMBs in a community based cohort of older men and women (born 1907-1935) who participated in the Age Gene/ Environment Susceptibility (AGES)-Reykjavik Study, a population based cohort study that followed the Reykjavik Study Methods: As part of the examination, all eligible and consenting cohort members underwent a full brain MRI, and blood was drawn for genotyping. Results are based on the first 1962 men (n= 820) and women (n= 1142), mean age 76 years, with complete MRI and demographic information available. Results: Evidence of CMBs was found in 218 participants (11.1% (95% CI 9.8% to 12.6%)); men had significantly more CMBs than women (14.4% vs 8.8%; p= 0.0002, age adjusted). The prevalence of CMBs increased with age (p= 0.0001) in both men (p= 0.006) and women (p= 0.007). CMBs were located in the cerebral lobes (70%), the basal ganglia region (10.5%) and infratentorium (18.6%). Having a CMB was significantly associated with a homozygote Apo E epsilon 4 epsilon 4 genotype (p= 0.01). Conclusion: Cerebral microbleeds are common in older persons. The association with homozygote Apo E epsilon 4 genotype and finding a relative predominance in the parietal lobes might indicate an association with amyloid angiopathy.