THE PREVALENCE AND SEVERITY OF WHITE-MATTER LESIONS, THEIR RELATIONSHIP WITH AGE, ETHNICITY, GENDER, AND CARDIOVASCULAR-DISEASE RISK-FACTORS - THE ARIC STUDY

White matter lesions (WMLs) detected by cerebral magnetic resonance im aging (MRI) are putatively a consequence of cerebral hypoperfusion or ischemia. We investigated the prevalence, severity and correlates of W MLs in a population-based sample of 1,920 African-American and Europea n-American men and women aged 55-72 years, during the second follow-up examination of the Atherosclerosis Risk in Communities Study. The spi n density images from 1.5-tesla MRI scans were used to define WMLs usi ng a 0-9 scale with 0 for normal and 9 for most severe WMLs. Age was p ositively associated with the prevalence (percent) and severity of WML s. African-Americans had a lower overall prevalence of WMLs, but a hig her prevalence of relatively more severe WMLs, than European-Americans . After adjusting for age, sex, and ethnicity, WMLs were significantly associated with smoking, lower education, hypertension, systolic bloo d pressure, and pulse pressure, and weakly associated with diastolic b lood pressure. The associations of smoking, alcohol intake, systolic a nd diastolic blood pressure, pulse, pressure, and hypertension were st ronger in African-Americans than in European-Americans (p < 0.15 for i nteractions by ethnicity). This population-based MRI study documents s ignificant relationships between several cardiovascular disease risk f actors and WMLs. The findings suggest that such factors play a role in the pathogenesis of WMLs, as elements linked to hypoperfusion and/or fluid accumulation, which presumably lead to WMLs. African-Americans e xhibited both a higher proportion of normal white matter and a higher proportion of relatively more severe WMLs than European-Americans.