Dietary folate and vitamins B-12 and B-6 not associated with incident Alzheimer's disease¹

Issue title: Folate and Homocysteine in Alzheimer's Disease

Guest editors: Thomas Shea

Article type: Research Article

Authors: Morris, Martha Clare^{a; b; c; *} | Evans, Denis A.^{a; b} | Schneider, Julie A.^{d; e} | Tangney, Christine C.^f | Bienias, Julia L.^{a; b} | Aggarwal, Neelum T.^{d; e}

Affiliations: [a] Rush Institute for Healthy Aging, Rush University Medical Center, Chicago, IL 60612, USA | [b] Department of Internal Medicine, Rush University Medical Center, Chicago, IL 60612, USA | [c] Department of Preventive Medicine, Rush University Medical Center, Chicago, IL 60612, USA | [d] Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA | [e] Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA | [f] Department of Clinical Nutrition Rush University Medical Center, Chicago, IL 60612, USA | Center for Cellular Neurobiology and Neurodegeneration Research, University of Massachusetts Lowell, Lowell, MA 01854, USA

Correspondence: [*] Corresponding author: Dr. Martha Clare Morris, Rush Institute for Healthy Aging, 1645 W. Jackson, Ste. 675, Chicago, IL 60612, USA. E-mail: Martha_C_Morris@rush.edu.

Note: [1] Supported by grants (AG11101 and AG13170) from the National Institute on Aging. The authors gratefully acknowledge the work of study coordinators, Cheryl Bibbs, Michelle Bos, Jennifer Tarpey, and Flavio Lamorticella, their staffs, and the analytic programmer, Hye-Jin Nicole Kim. Dr. Aggarwal is a paid consultant to Pfizer/Eisai.

Abstract: Context:It is currently not known whether dietary intakes of folate and vitamins B12 and B6, co-factors in the methylation of homocysteine, protect against Alzheimer’s disease. Objective:To examine the association between risk of incident Alzheimer’s disease and dietary intakes of folate, vitamin B-12, and vitamin B-6. Design:Prospective cohort study. Setting:Geographically defined biracial Chicago community. Participants:1,041 residents, aged 65 years and older, initially free of Alzheimer’s disease and followed a median 3.9 years for the development of incident disease. Main Outcome Measure:Probable Alzheimer’s disease identified through structured clinical neurological evaluation using standardized criteria. Results:A total of 162 persons developed incident Alzheimer’s disease during follow-up. In logistic regression models adjusted for age, sex, race, education, cognitive activities, APOE-ε4, and dietary intakes of vitamin E in food and total niacin, there was no association between risk of developing Alzheimer’s disease and quintiles of folate intake or of vitamin B-12 intake. The adjusted odds ratio was 1.6 (95% confidence interval: 0.5, 5.2) for persons in the highest quintile of total folate intake (median of 752.7 μg/d) compared with persons in the lowest quintile of intake (median, 202.8 μg/d). Compared with persons in the first quintile of total vitamin B-12 intake (median, 3.1 μg/d) the odds ratio was 0.6 (95% confidence interval: 0.2, 1.6) for persons in the fifth quintile of intake (median, 20.6 μg/d). Intake of vitamin B-6 was not associated with incident Alzheimer’s disease after control for dietary intakes of vitamin E and total niacin. Conclusion:Dietary intakes of folate, vitamin B-12, or vitamin B-6 do not appear to be associated with the development of Alzheimer’s disease.

Keywords: Folate, folic acid, vitamin B-12, vitamin B-6, Alzheimer's disease, dementia, aging

DOI: 10.3233/JAD-2006-9410

Journal: Journal of Alzheimer's Disease, vol. 9, no. 4, pp. 435-443, 2006