Vitamin D is associated with cognitive function in elders receiving home health services.
BACKGROUND
The objective of this study was to examine the association between 25-hydroxyvitamin D, 25(OH)D, and cognitive function.


METHODS
A cross-sectional investigation of 25(OH)D and cognition was completed in 377 black and 703 non-black (mainly Caucasian) elders (65-99 years) participating in the nutrition and memory in elders study. Participants underwent a comprehensive neuropsychological battery, and 25(OH)D concentrations were obtained.


RESULTS
More than 65% of elders had suboptimal 25(OH)D concentrations (< or =20 ng/mL or < or =50 nmol/L). Approximately 18% were deficient in 25(OH)D (<10 ng/mL or <25 nmol/L). After adjusting for age, sex, race, body mass index, education, center, kidney function, seasonality, physical activity, and alcohol use, 25(OH)D was associated with better performance on trails A (beta = -0.49, p < .03), trails B (beta = -0.73, p < .02), digit symbol (beta = 0.19, p < .001), matrix reasoning (beta = 0.04, p < .02), and block design (beta = 0.07, p < .04) tests. Associations remained after adjustment for homocysteine, apoE4 allele, plasma B vitamins, and multivitamin use (y/n). 25(OH)D concentrations >20 ng/mL were associated with better performance on tests of executive function, including trails A (80.5 vs 95, p < .05), trails B (205s vs 226s, p < .05), matrix reasoning (7.8 vs 7.0, p = .03), and digit symbol (31.5 vs 37, p < .01). There were no associations between 25(OH)D and memory tests. Factor analysis yielded factors for memory, executive function, and attention/processing speed. After adjustment, 25(OH)D was associated with the executive function (beta = 0.01, p < 0.01) and attention/processing speed factors (beta = 0.01, p = .03), but not the memory factor (beta = -0.001, p = 0.65).


CONCLUSIONS
25(OH)D was positively associated with cognitive performance, particularly with measures of executive function in this elderly population.
Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington Street, Boston, MA 02111, USA.
Jennifer S
JS
Buell
Tammy M
TM
Scott
Bess
B
Dawson-Hughes
Gerard E
GE
Dallal
Irwin H
IH
Rosenberg
Marshal F
MF
Folstein
Katherine L
KL
Tucker
D000368:Aged; D000369:Aged, 80 and over; D003071:Cognition; D003430:Cross-Sectional Studies; D005260:Female; D006296:Health Services; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D025341:Principal Component Analysis; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000523:psychology
D014807:Vitamin D; C104450:25-hydroxyvitamin D