Abstract
We studied incidence, risk factors and prognosis of silent brain infarction (SBI) in more than 3, 000 people who undertook brain check-up since 1988. SBI increases linearly as a function of age after the age of 50s. The most potent risk factor for SBI was a medical history of hypertension (odds ratio = 3.2). Other factors included age, male sex and high level of blood glucose. The risk of symptomatic stroke occurrence was 10 times higher in those with SBI (annual incidence = 2.8%) compared to those without SBI (0.3%). The number of microbleeds in T2 * image was correlated with the number of SBI and was related to blood pressure level. A long-term follow-up study showed that the occurrence of cerebral hemorrhage was not low (22%) in those with SBI, although cerebral infarction was most frequent (66%). The follow-up study also demonstrated that cognitive impairments were associated with the increase of SBI. The cognitive deterioration was more closely related to the worsening of white matter changes, which also had a strong association with hypertension. These results suggest that the management of SBI and its risk factors, especially hypertension, is critical for preventing subsequent stroke occurrence and cognitive deterioration.
