Vascular risk factors and longitudinal changes on brain MRI: the ARIC study

Abstract

Objective: To evaluate associations between vascular risk factors and changes in burden of infarcts, ventricular size (VS), sulcal widening (SW), and white matter hyperintensities (WMH) in an initially middle-aged, biracial cohort from the Atherosclerosis Risk in Communities (ARIC) study.

Methods: Initial brain magnetic resonance (MR) scans and evaluations for vascular risk factors were performed in 1,812 ARIC participants in 1994-1995. In 2004-2006, 1,130 ARIC participants underwent repeat MR scans. MR scans were rated using a validated 9-point scale for VS, SW, and WMH. Infarcts were recorded. Multiple logistic regression analysis was used to assess associations between vascular risk factors and change between MR scans of one or more grades in VS, SW, WMH, or appearance of new infarcts, controlling for age, sex, and race.

Results: At baseline, the 1,112 participants with usable scans (385 black women, 200 black men, 304 white women, 223 white men) had a mean age of 61.7 ± 4.3 years. In adjusted models, diabetes at baseline was associated with incident infarcts (odds ratio [OR] 1.95, 95% confidence interval [CI] 1.29-2.95) and worsening SW (OR 2.10, 95% CI 1.36-3.24). Hypertension at baseline was associated with incident infarcts (OR 1.73, 95% CI 1.23-2.42). In subjects with the highest tertile of fasting blood sugar and systolic blood pressure at baseline, the risk of incident infarcts was 3.68 times higher (95% CI 1.89-7.19) than those in the lowest tertile for both.

Conclusion: Both atrophic and ischemic imaging changes were driven by altered glycemic and blood pressure control beginning in midlife.

Figure 1. Odds ratios of new infarcts by combinations of fasting blood glucose levels and systolic blood pressure in all subjects

Tertiles of baseline systolic blood pressure are depicted on the x-axis, tertiles of baseline fasting glucose are depicted on the y-axis, and odds ratios on the z-axis. The reference group is the lowest tertile for both systolic blood pressure and fasting blood glucose. Gray bars indicate odds ratios that did not include 1. The odds ratio of the group with the highest tertile of systolic blood pressure and highest fasting blood glucose level was 3.68 (95% confidence interval 1.89–7.19).