Concentrations of amyloid-beta protein in cerebrospinal fluid increase with age in patients free from neurodegenerative disease.

Cerebral deposition of amyloid-beta protein (A beta) is central to the pathogenesis of Alzheimer's disease (AD). Increasing age is one of the few definitively established risk factors for this disease. The concentration of A beta was measured in cerebrospinal fluid (CSF) with a sensitive enzyme-linked immunosorbent assay in 18 adult neurological patients free from neurodegenerative disease. CSF A beta increased with age, yielding a significant correlation of 0.84. This observation suggests that increased levels of A beta in CSF may be an index of age-related changes in the processing of the amyloid-beta precursor protein resulting in an increased risk for AD.