[SCIs are brain injuries likely caused by blood clots interrupting blood flow in the brain, associated with high blood pressure and artery disease. They go unnoticed, but are considered a sign of progressive brain damage that may result in long-term dementia, and a risk factor for future “clinical” strokes and atrial fibrillation.]
Background and Purpose: Previous estimates of the prevalence of silent cerebral infarction (SCI) on MRI in community-based samples have varied between 5.8% and 17.7% depending on age, ethnicity, presence of comorbidities, and imaging techniques. We document the prevalence and risk factors associated with SCI at midlife in the community-based Framingham sample.
Methods: Our study sample comprised 2,040 Framingham Offspring (53% female; mean age, 62±9 years) who attended the sixth examination (1996–1998), underwent volumetric brain MRI (1999–2005,) and were free of clinical stroke at MRI. We examined the age- and sex-specific prevalences and the clinical correlates of SCI using multivariable logistic regression models.
Results: At least 1 SCI was present in 10.7% of participants; 84% had a single lesion. SCI was largely located in the basal ganglia (52%), other subcortical (35%) areas, and cortical areas (11%). Prevalent SCI was associated with the Framingham Stroke Risk Profile score (OR, 1.27; 95% CI, 1.10–1.46); stage I hypertension was determined by JNC-7 criteria (OR,1.56; CI,1.15–2.11), an elevated plasma homocysteine in the highest quartile (OR, 2.23; CI, 1.42–3.51), atrial fibrillation (OR, 2.16; CI, 1.07–4.40), carotid stenosis >25% (OR, 1.62; 1.13–2.34), and increased carotid intimal-medial thickness above the lowest quintile (OR, 1.65; CI, 1.22–2.24).
Conclusion: The prevalence and distribution of SCI in the Framingham Offspring are comparable to previous estimates. Risk factors previously associated with clinical stroke were also found to be associated with midlife SCI. Our results support current guidelines emphasizing early detection and treatment of stroke risk factors.
[Note: To read about the Framingham Heart Study, which since 1948 has tracked and analyzed the cardiovascular health of men and women in the town of Framingham, Massachusetts, click here.]
Source: Stroke, June 26, 2008 [E-pub ahead of print.] PMID: 18583555, by Das RR, Seshadri S, Beiser AS, Kelly-Hayes M, Au R, Himali JJ, Kase CS, Benjamin EJ, Polak JF, O’Donnell CJ, Yoshita M, D’Agostino RB Sr, Decarli C, Wolf PA. Departments of Neurology, Biostatistics, Preventive Medicine, Medicine, and Mathematics, Boston University; Department of Radiology, Tufts University, Boston; The Framingham Heart Study and National Heart Lung and Blood Institute, Framingham, Massachusetts; Department of Neurology, University of California-Davis, Davis, California. [E-mail: firstname.lastname@example.org]