Plasma total homocysteine and memory in the elderly: the Hordaland Homocysteine Study.
We examined the relation between plasma total homocysteine (tHcy), folate, vitamin B12, and episodic memory in elderly community-dwelling subjects. A population-based study was conducted in 1992 and 1993, and subjects were re-investigated after 6 years. Plasma analytes were determined on both occasions. At follow-up, memory performance, using the Kendrick Object Learning Test, was investigated in 2,189 subjects (age, 65-67 years at baseline). Subjects with memory deficit (test score, < 25) had higher tHcy and lower folate at follow-up compared with those without memory deficit: 12.6 (95% confidence interval [CI], 12.1, 13.1) versus 11.5 (95% CI, 11.3, 11.6) micromol/L (p < 0.001) for tHcy, and 6.7 (95% CI, 6.2, 7.1) versus 7.6 (95% CI, 7.5, 7.8) nmol/L (p < 0.001) for folate. The risk of memory deficit increased according to quintiles of tHcy both at baseline and at follow-up. A decline in tHcy, or an increase in folate, over a 6-year period was associated with a higher memory test score; and vice versa. These findings indicate that increased plasma tHcy is an independent risk factor for memory deficit both cross-sectionally and prospectively, and that a "favorable" change in folate or tHcy concentrations over time is associated with better memory performance.
Nurk
Eha
E
Department of Pharmacology, Oxford Project to Investigate Memory and Ageing (OPTIMA), University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom.
Refsum
Helga
H
Tell
Grethe S
GS
Engedal
Knut
K
Vollset
Stein E
SE
Ueland
Per M
PM
Nygaard
Harald A
HA
Smith
A David
AD
D000368:Aged; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D005492:Folic Acid / Q000097:blood; D005500:Follow-Up Studies; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008568:Memory; D008569:Memory Disorders / Q000097:blood* / Q000453:epidemiology*; D011446:Prospective Studies; D012307:Risk Factors; D014805:Vitamin B 12 / Q000097:blood
D015415:Biomarkers; D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12