Brain atrophy and white matter hyperintensity change in older adults and relationship to blood pressure

Abstract

Hypertension is a major risk factor for stroke and dementia and is associated with white matter hyperintensities (WMH) and reduced brain volumes. We measured the increase in WMH volume, and rate of cerebral atrophy over two years, in hypertensive subjects participating in the Study on COgnition and Prognosis in the Elderly (SCOPE), receiving candesartan or placebo, and normotensive controls. We recruited 163 subjects who had MRI (FLAIR and volumetric T1) at 2 and 4 years after baseline assessment. From these two scans, volumetric change in WMH (n = 133) and brain atrophy rates (n = 95) were determined. Total WMH fraction increased in both normotensive and treated hypertensive groups (p < 0.01) median change: 0.05% of brain volume [range: -0.45% to 1.51%]. Deep WMH increased in hypertensive (p = 0.001) but not the normotensive group. The number of subjects with an increase of total WMH in the 5(th) quintile differed between the treatment groups (chi square p = 0.006), being greatest in the placebo group (32%), then candesartan (20%) then normotensive (5%). Regression analysis found significant predictors of change in WMH to be blood pressure and initial deep WMH, but not treatment group. Increased atrophy rate was predicted by baseline systolic blood pressure (p = 0.02) but was not associated with measures of WMH. Similar to WMH, there was a trend with treatment, with atrophy in normotensive < Candesartan < Placebo (Spearman's rho = 0.23, p = 0.026). Hypertension in older people is associated with increased rates of progressive whole brain atrophy and an increase in WMH. These changes are independent. Successful hypertension treatment was associated with reduced risk of WMH progression and possibly brain atrophy.