Background and Purpose--Incidental findings of infarcts on brain imaging are common, but their clinical significance is not clear. We examined the prevalence of symptomatic and silent infarcts on cranial computerized tomography (cCT) and their relation to dementia and mortality in a representative sample of 239 85-year-olds living in Gothenburg Sweden.

Methods--Information on stroke was obtained from an inpatient hospital linkage system, self-reports, and key informants. Dementia was defined according to the Diagnostic and Statistical Manual of Mental Disorders, 3rd revision. Cortical and lacunar infarcts were diagnosed on cCT.

Results--The prevalence of cerebral infarcts was 17.1%, and half of those were clinically silent (8.6%). The frequency of dementia was increased in those with symptomatic (OR, 5.5; 95% CI, 2.1 to 14.1) and silent infarcts (OR, 2.7; 95% CI, 1.1 to 6.7). Infarcts increased the risk for dementia and its severity in women but not in men. The 3-year mortality rate was increased in those with symptomatic (OR, 4.0; 95% CI, 1.6 to 9.6) and silent infarcts (OR, 3.4; 95% CI, 1.4 to 8.5).

Conclusions--Almost one fifth of 85-year-olds have infarcts on cCT, and half of those are clinically silent. These infarcts are related to an increased rate of dementia and 3-year mortality. Cerebrovascular disease as a cause of dementia may be underrated because of silent infarcts. It has to be elucidated whether treatment of risk factors for stroke may reduce the consequences of silent infarcts.