Relation of higher folate intake to lower risk of Alzheimer disease in the elderly.
BACKGROUND
Higher intake of folate and vitamins B6 (pyridoxine hydrochloride) and B12 (cyanocobalamin) may decrease the risk of Alzheimer disease (AD) through the lowering of homocysteine levels.


OBJECTIVE
To relate intake of folate and vitamins B6 and B12 to AD risk.


METHODS
We followed up 965 persons 65 years or older without dementia at baseline for a mean +/- SD period of 6.1 +/- 3.3 person-years after the administration of a semiquantitative food frequency questionnaire. Total, dietary, and supplement intake of folate and vitamins B6 and B12 and kilocalorie intake were estimated from the questionnaire responses. We related energy-adjusted intake of folate and vitamins B6 and B12 to incident AD using the Cox proportional hazards regression model.


METHODS
Incident AD.


RESULTS
We found 192 cases of incident AD. The highest quartile of total folate intake was related to a lower risk of AD (hazard ratio, 0.5; 95% confidence interval, 0.3-0.9; P=.02 for trend) after adjustment for age, sex, education, ethnic group, the epsilon4 allele of apolipoprotein E, diabetes mellitus, hypertension, current smoking, heart disease, stroke, and vitamin B6 and B12 levels. Vitamin B6 and B12 levels were not related to the risk of AD.


CONCLUSIONS
Higher folate intake may decrease the risk of AD independent of other risk factors and levels of vitamins B6 and B12. These results require confirmation with clinical trials.
Luchsinger
José A
JA
Taub Institute for Research of Alzheimer's Disease and the Aging Brain, Joseph P. Mailman School of Public Health, Columbia University, New York, NY, USA. jal94@columbia.edu
Tang
Ming-Xin
MX
Miller
Joshua
J
Green
Ralph
R
Mayeux
Richard
R
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000517:prevention & control*; D019587:Dietary Supplements; D002149:Energy Intake; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012306:Risk; D011795:Surveys and Questionnaires; D014803:Vitamin B Complex / Q000008:administration & dosage*
D014803:Vitamin B Complex; D005492:Folic Acid