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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #307587
Title: Low 25-hydroxyvitamin D levels and cognitive impairment in hemodialysis patients

Author
item SHAFFI, KAMRAN - TUFTS - NEW ENGLAND MEDICAL CENTER
item TIGHIOUART, HOCINE - TUFTS - NEW ENGLAND MEDICAL CENTER
item SCOTT, TAMMY - JEAN MAYER HUMAN NUTRITION RESEARCH CENTER ON AGING AT TUFTS UNIVERSITY
item LOU, KRISTINA - TUFTS - NEW ENGLAND MEDICAL CENTER
item DREW, DAVID - TUFTS - NEW ENGLAND MEDICAL CENTER
item WEINER, DANIEL - TUFTS - NEW ENGLAND MEDICAL CENTER
item SARNAK, MARK - TUFTS - NEW ENGLAND MEDICAL CENTER

Submitted to: Journal of the American Society of Nephrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2013
Publication Date: 6/1/2013
Citation: Shaffi, K., Tighiouart, H., Scott, T., Lou, K., Drew, D., Weiner, D., Sarnak, M. 2013. Low 25-hydroxyvitamin D levels and cognitive impairment in hemodialysis patients. Journal of the American Society of Nephrology. 8(6):979-986.

Interpretive Summary: Vitamin D de'ciency and cognitive impairment are both prevalent in hemodialysis patients in the United States. This study tested the hypothesis that vitamin D de'ciency may be associated with cognitive impairment because of it protects the neurons and the vascular system from damage, and has properties that modulate the immune system. In a group of 255 patients receiving hemodialysis, we found that 69% of patients had vitamin D concentrations in their blood that were in either the deficient or insufficient ranges. Patients in the de'cient group were more likely to be women, African American, and diabetic and to have been on dialysis for longer periods of time. Higher vitamin D levels were independently associated with better performance on several tests of executive function (e.g. mental flexibility, organization, and planning). No association was seen with tests assessing memory.

Technical Abstract: 25-hydroxyvitamin D (25[OH]D) deficiency and cognitive impairment are both prevalent in hemodialysis patients in the United States. This study tested the hypothesis that 25(OH)D deficiency may be associated with cognitive impairment because of its vasculoprotective, neuroprotective, and immune-modulatory properties. This cross-sectional analysis involved 255 patients enrolled in the Dialysis and Cognition Study between 2004 and 2012. In linear regression models, 25(OH)D was the exposure variable; it was used first as a continuous variable and then stratified as deficient (<12 ng/ml), insufficient (12 to <20 ng/ml), and sufficient (greater than or equal to20 ng/ml). Principal component analysis was used to obtain the memory and the executive function domains from the individual neurocognitive tests. Scores on individual tests as well as on the memory and executive function domains were the outcome variables. Multivariable models were adjusted for age, sex, race, education, and other potential confounding variables. Mean serum 25(OH)D +/- SD was 17.2+/-7.4 ng/ml, with 14%, 55%, and 31% of patients in the deficient, insufficient, and sufficient groups, respectively. Patients in the deficient group were more likely to be women, African American, and diabetic and to have longer dialysis vintage. Higher 25(OH)D levels were independently associated with better performance on several tests of executive function (mean difference on component executive score, 0.16 [95% confidence interval, 0.04-0.28; P=0.01] for each SD higher 25[OH]D). No association was seen with tests assessing memory. 25(OH)D deficiency in hemodialysis patients is associated with worse cognitive function, particularly in domains that assess executive function.