A POPULATION STUDY ON BLOOD-BRAIN-BARRIER FUNCTION IN 85-YEAR-OLDS - RELATION TO ALZHEIMERS-DISEASE AND VASCULAR DEMENTIA

We investigated blood-brain barrier (BBB! function in relation to Alzh eimer's disease (AD) and vascular dementia (VAD) in the very elderly. Sixty-five 85-year-old persons from a population-based sample were fol lowed for 3 years; 29 were demented at age 85 (13 with AD, 14 with VAD , and 2 with other dementias), 7 developed dementia during follow-up, and 29 remained nondemented. CSF/serum albumin ratio was used as as a measure of BBB function. Dementia was defined according to the DSM-III -R, AD according to the NINCDS-ADRDA criteria, and VAD according to th e NINDS-Association Internationale pour la Recherche et l'Enseignement en Neurosciences (AIREN) criteria, Mean CSF/serum albumin ratio was h igher in all dementias (8.5 +/- 4.3; p = 0.007) and in the subtypes AD (8.9 +/- 5.3; p = 0.046) and VAD (8.7 +/- 3.5; p = 0.002) than in non demented individuals (versus 6.5 +/- 2.0), but it was not related to d ementia severity. Nondemented women at age 85 (n = 3) who developed de mentia during the follow-up had a higher CSF/serum albumin ratio than those not developing dementia (10.4 +/- 2.0 versus 6.0 +/- 1.9; p = 0. 007). Nondemented individuals lacking the apolipoprotein E epsilon 3 a llele (n = 4) had a higher CSF/serum albumin ratio (9.3 +/- 0.8 versus 6.6 +/- 2.1;p = 0.029) than other individuals. A relative BBB dysfunc tion is associated with both AD and VAD among very elderly individuals . This finding is possibly found early in the disease before the onset of clinical dementia.