CSF biomarker levels in early and late onset Alzheimer's disease

Objective To compare CSF levels of beta-amyloid 1-42 (A beta(1-42)), total tau (tau) and tau phosphorylated at threonine 181 (ptau-181) between AD patients and controls according to age Methods. 248 AD patients (48% men) and 127 controls (51% men, 22 volunteers and 105 subjective complainers) underwent lumbar puncture. Both patients and controls were divided into a young (<65 years) and old (>= 65 years) group Results. All three biomarkers showed main effects of diagnosis (p<0.001). There was an interaction between diagnosis and age for all three biomarkers (p<0.05), as old controls had lower A beta(1-42) and higher(p)tau than young controls (A beta(1-42) 699 +/- 250 versus 8.56 +/- 191 pg/ml, tau 408 +/- 245 versus 243 +/- 102 pg/ml, ptau-181 60 +/- 28 versus 42 +/- 15pg/ml), but there was no difference according to age among AD patients (A beta(1-42) 451 +/- 178 versus 425 +/- 146 pg/ml, tau 741 +/- 460 versus 798 +/- 467 pg/ml, ptau-181 91 +/- 42 versus 91 +/- 41pg/ml). Conclusion: We found that the older control group had lower A beta(1-42) and higher (p)tau compared to the younger control group This suggests that older individuals may have AD patholoay, even in the absence of objective cognitive impairment. (C) 2008 Elsevier Inc. All rights reserved.