Elevated Plasma Homocysteine Levels and Risk of Silent Brain Infarction in Elderly People

Background and Purpose Silent brain infarction (SBI) on MRI is common in elderly people, and recent studies have demonstrated that SBI increases the risk of progression to clinically apparent stroke and cognitive decline. Therefore, an early and accurate detection of SBI and a search for potential treatable risk factors may have a significant impact on public health. Methods Community-dwelling elderly people aged ≥66 years who participated in the present study (n=153) underwent brain MRI and standardized physical and neuropsychological examinations as well as blood biochemistry determinations, including total plasma homocysteine (pHcy), renal function, vitamin status, and polymorphisms of the methylenetetrahydrofolate reductase gene. Results SBI was found in 24.8% of the participants. In the univariate analysis, the pHcy levels in subjects with SBI (13.6±4.1 &mgr;mol/L) were significantly higher (P =0.0004) than those in subjects without SBI (11.0±3.3 &mgr;mol/L). When pHcy levels were stratified into high (≥15.1 mmol/L), moderate (11.6 to 15.0 mmol/L), and low (≤11.5 mmol/L) groups, age (P <0.0001), male sex (P <0.0001), the habits of cigarette smoking (P <0.0001) and of alcohol consumption (P =0.0002), and folate levels (P =0.01) were significantly associated with an elevation of pHcy levels. The elevated pHcy levels were significantly associated with SBI after individual adjustment for age, sex, hypertension, renal function, and the habits of smoking and alcohol consumption. Conclusions pHcy level is associated with age and nutritional and other lifestyle factors, and it contributes to a risk for SBI.