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Background White matter changes (WMC) on brain imaging, reflecting chronic subcortical ischaemia, increase steeply with age. Hypertension is a risk factor for WMC, particularly in younger patients, and variability in blood pressure (BP) is a risk factor for acute stroke. However, the relative contribution of long-term mean BP versus BP variability to the development of WMC is uncertain. We determined these associations based on all BP measures over a 10-year period. Methods In consecutive TIA or stroke patients, we collected all pre-morbid BPs from primary care. We rated WMC on CT or MRI with four scales, and calculated their age-specific associations with 10-year measurements of BP parameters (mean systolic and diastolic BP and average visit-to-visit variability ie, the mean difference between successive measures). Results 520 MRI and 1717 CT were assessed. Results were similar for CT and MRI and for different WMC scales. 10-year mean SBP was strongly associated with WMC at age Conclusions Increased 10-year mean SBP and DBP were associated with WMC, but we found no association with BP variability, consistent with the hypothesis that raised long-term mean BP results in chronic subcortical ischaemia whereas variability in BP is associated with an increased risk of acute events. |
