Beta-Amyloid in Plasma Predicts Cognitive Decline

By John Gever, Senior Editor, MedPage Today Published: January 18, 2011 Reviewed by Zalman S. Agus, MD; Emeritus Professor University of Pennsylvania School of Medicine. Action Points   Note that this study indicates that differences in proteins and peptides can be found in peripheral fluids years before clinical onset of dementia. Point out, however, that documentation of an association is not sufficient to prove that any given compound is a true biomarker of actual disease. The ratio of two beta-amyloid protein species in plasma was associated with subsequent cognitive decline in older patients, researchers said. Patients who did not have dementia at baseline but who had a relatively low ratio of the 42- to 40-amino acid form of beta-amyloid showed almost twice the decline in cognitive function scores over a nine-year period than was seen in otherwise similar patients with relatively high beta-amyloid 42/40 ratios, according to Kristine Yaffe, MD, of the University of California San Francisco, and colleagues. Scores on the modified Mini-Mental State Examination declined an average 6.59 points among individuals in the lowest third of beta-amyloid 42/40 ratios, compared with a 3.60-point decline in patients in the highest tertile (P<0.001), the researchers reported in the Jan. 19 issue of the Journal of the American Medical Association./.../