title: Homocysteine, vitamin B12, and folic acid levels in Alzheimer's disease, mild cognitive impairment, and healthy elderly: baseline characteristics in subjects of the Australian Imaging Biomarker Lifestyle study.
abstract: There is some debate regarding the differing levels of plasma homocysteine, vitamin B12 and serum folate between healthy controls (HC), mild cognitive impairment (MCI), and Alzheimer's disease (AD). As part of the Australian Imaging Biomarker Lifestyle (AIBL) study of aging cohort, consisting of 1,112 participants (768 HC, 133 MCI patients, and 211 AD patients), plasma homocysteine, vitamin B12, and serum and red cell folate were measured at baseline to investigate their levels, their inter-associations, and their relationships with cognition. The results of this cross-sectional study showed that homocysteine levels were increased in female AD patients compared to female HC subjects (+16%, p-value < 0.001), but not in males. Red cell folate, but not serum folate, was decreased in AD patients compared to HC (-10%, p-value = 0.004). Composite z-scores of short- and long-term episodic memory, total episodic memory, and global cognition all showed significant negative correlations with homocysteine, in all clinical categories. Increasing red cell folate had a U-shaped association with homocysteine, so that high red cell folate levels were associated with worse long-term episodic memory, total episodic memory, and global cognition. These findings underscore the association of plasma homocysteine with cognitive deterioration, although not unique to AD, and identified an unexpected abnormality of red cell folate.
authors: The Mental Health Research Institute, The University of Melbourne, Parkville, VIC, Australia.
authors: Noel G
authors: NG
authors: Faux
authors: Kathryn A
authors: KA
authors: Ellis
authors: Lorine
authors: L
authors: Porter
authors: Chris J
authors: CJ
authors: Fowler
authors: Simon M
authors: SM
authors: Laws
authors: Ralph N
authors: RN
authors: Martins
authors: Kelly K
authors: KK
authors: Pertile
authors: Alan
authors: A
authors: Rembach
authors: Chris C
authors: CC
authors: Rowe
authors: Rebecca L
authors: RL
authors: Rumble
authors: Cassandra
authors: C
authors: Szoeke
authors: Kevin
authors: K
authors: Taddei
authors: Tania
authors: T
authors: Taddei
authors: Brett O
authors: BO
authors: Trounson
authors: Victor L
authors: VL
authors: Villemagne
authors: Vanessa
authors: V
authors: Ward
authors: David
authors: D
authors: Ames
authors: Colin L
authors: CL
authors: Masters
authors: Ashley I
authors: AI
authors: Bush
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood* / Q000473:pathology; D000544:Alzheimer Disease / Q000097:blood* / Q000473:pathology; D000704:Analysis of Variance; D001315:Australia; D001921:Brain / Q000473:pathology; D060825:Cognitive Dysfunction / Q000097:blood* / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage / Q000097:blood*; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D014805:Vitamin B 12 / Q000097:blood*
chemical_list: D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12