Ambulatory blood pressure and brain atrophy in the healthy elderly

BACKGROUND: Brain lesions and atrophy increase with age and hypertension. OBJECTIVE: To evaluate the relationship of age and ambulatory blood pressure (BP) to brain atrophy in healthy elderly individuals. METHODS: MRI volume measurements (normalized to intracranial volume) were taken of total brain and lateral and third ventricles in 155 healthy men and women who went through extensive medical examinations. Younger (56 to 66 years old) and older (67 to 80 years old) subgroups were compared on casual and 24-hour ambulatory BP values and MRI volume measurements. RESULTS: Older subjects had smaller brain volumes and larger lateral and third ventricles. Compared with women, men had larger lateral and third ventricles. With age controlled for, greater sleep systolic BP (SBP) variability was associated with smaller brain volumes; greater waking and sleep SBP variability were associated with larger lateral and third ventricles. Subjects with higher casual and waking SBP and waking diastolic BP had larger lateral ventricles. Among older subjects, only those with elevated SBP had smaller brain volumes and larger lateral ventricles. CONCLUSIONS: These results indicate that if BP levels are within the upper normal range, even healthy individuals with no prior diagnosis of hypertension are more likely to have brain atrophy than those with lower BP. Moreover, not only do BP level and variability relate to brain atrophy, but the combination of high level and greater variability shows an even stronger relationship to brain atrophy than either one of these variables alone.