Incidence of cerebral microbleeds in the general population: the Rotterdam Scan Study.

BACKGROUND AND PURPOSE

Cerebral microbleeds are frequently seen in the general elderly population, but it is unknown at what rate they occur with aging and whether once present can disappear over time.

METHODS

As part of the Rotterdam Scan Study, 831 persons (mean age, 68.5 years) underwent repeated brain MRI with a mean interval of 3.4 years. We assessed determinants of incident microbleeds in relation to their location with multiple logistic regressions.

RESULTS

Overall prevalence of microbleeds increased from 24.4% at baseline to 28.0% at follow-up. Eighty-five persons (10.2%) developed new microbleeds. Microbleeds at baseline predicted development of new microbleeds (OR, 5.38; 95% CI, 3.34 to 8.67). In only 6 persons with microbleeds at baseline, fewer microbleeds were present at the follow-up examination. Cardiovascular risk factors, presence of lacunar infarcts, and larger white matter lesion volume at baseline were all associated with incident deep or infratentorial microbleeds, whereas people with the apolipoprotein E ε4/ε4 genotype or larger white matter lesion volume had a higher risk of incident strictly lobar microbleeds.

CONCLUSIONS

Incidence of microbleeds in the general population over a 3-year interval was substantial and microbleeds rarely disappeared. Risk factors for incident microbleeds were similar to those for prevalent microbleeds and differed according to microbleed location. These results support the assessment of microbleeds on T2-weighted MRI as a possible marker of both cerebral amyloid angiopathy and hypertensive vasculopathy progression.