Depression is associated with low plasma Abeta42 independently of cardiovascular disease in the homebound elderly.
BACKGROUND
Depression often precedes the onset of Alzheimer's disease (AD) before the appearance of cognitive symptoms. Plasma Amyloid-beta peptide 42 (Abeta42) declines before and soon after the onset of AD, yet the relationship between plasma Abeta42 and depression is unclear.


METHODS
We used 515 homebound elders aged 60 and older in a population-based, cross-sectional study to investigate associations between plasma Abeta levels and depression with and without cardiovascular co-morbidities. Depression was evaluated by using the Center for Epidemiological Studies Depression (CES-D) scale. Plasma Abeta40 and Abeta42 were measured.


RESULTS
The elderly with depression had lower plasma Abeta42 (median: 15.3 vs. 18.9, p = 0.008) than those without depression. The CES-D score was inversely associated with plasma Abeta42 (p = 0.001) in subjects with no cardiovascular disease (CVD); however, in the presence of CVD, this association did not exist. Low plasma Abeta42 (OR = 0.41, p = 0.007) and the presence of CVD (OR = 1.84, p = 0.005) were independently associated with depression after adjusting for the confounders of age, stroke and apolipoprotein E4.


CONCLUSIONS
Depressive symptoms are associated with low plasma Abeta42 independently of CVD. Prospective studies are needed to determine whether depression associated with low plasma Abeta42 is a separate depression subtype that could predict the onset of AD.
Qiu
Wei Qiao
WQ
Department of Psychiatry, Tufts-New England Medical Center, Tufts University School of Medicine, Boston, MA, USA. wqiu@tufts-nemc.org
Sun
Xiaoyan
X
Selkoe
Dennis J
DJ
Mwamburi
D Mkaya
DM
Huang
Tina
T
Bhadela
Refeeque
R
Bergethon
Peter
P
Scott
Tammy M
TM
Summergrad
Paul
P
Wang
Lixia
L
Rosenberg
Irwin
I
Folstein
Marshal
M
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D016229:Amyloid beta-Peptides / Q000097:blood*; D002318:Cardiovascular Diseases / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D005260:Female; D018577:Homebound Persons / Q000523:psychology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood*; D012016:Reference Values; D014481:United States
D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42)