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Citation
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Lopez J, Campa A, Lewis JE, Huffman FG, Liuzzi JP, Li T, Martinez AH, Ferris SM, Rasul A, Farooqi A, Lopez Medrano AM, Atlas SE, Tiozzo E, Konefal J, Woolger JM. J. Prev. Alzheimers Dis. 2017; 4(1): 29-36. |
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Affiliation
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Johanna Lopez, Ph.D., RDN/LDN. Clinical and Research Dietitian, Division of Gastroenterology, University of Miami Miller School of Medicine, Miami, FL 33136 jlopez2@miami.edu Ph: 305-243-4113 or 786-973-2363 Fax: 305-243-1619. |
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Abstract
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BACKGROUND: Vitamin D deficiency has been associated with an increased risk of falls in older adults. Several studies have demonstrated an association between vitamin D deficiency and gait and cognitive impairments, which are two risk factors for falls in the elderly. There is lack of research about the role of vitamin D in cognitive function in the context of mobility.
OBJECTIVE: The purpose of this study was to evaluate the association between vitamin D status with the age-related changes in mobility through higher order cognitive function using a dual task physical performance test.
DESIGN: Cross-sectional. SETTING: Community-dwelling older adult population located in Miami, Fl. PARTICIPANTS: Healthy participants over the age of 55 (n=97) who participated in the parent interventional study. MEASUREMENTS: Participants completed assessments that included serum levels of vitamin D, surveys, and dual task physical performance tests. Spearman's correlations, independent t-tests, repeated measures ANOVAs and multiple logistic regressions were used to examine the relationship between vitamin D insufficiency (25-hydroxyvitamin D <30 ng/ml) and sufficiency (≥30 ng/ml) and dual task physical performance variables. The significance level was set at α=0.05.
RESULTS: There were no significant associations between vitamin D insufficiency and gait velocity during either task. Using Spearman correlations, slower single (P=0.011) and dual task counting rates (P=0.006) were significantly associated with vitamin D insufficiency. Independent t-tests showed dual and single task counting rates were significantly lower in the vitamin D insufficient group compared to the sufficient group (P=0.018 and P=0.028, respectively). The results for the ANOVAs indicated that velocities and counting rates were not significantly different by vitamin D status (Wilk's Lambda =0.999; F (1, 95) =.11, P=.740) (Wilk's Lambda =.999, F(1,95)=.13, P=.718). Vitamin D status was not significantly associated with dual task physical performance (defined as the difference in dual and single task) in gait velocity (OR=1.00, 95% CI: 0.98; 1.02, P=0.772) and counting rate (OR=1.684, 95% CI: 0.15; 19.57, P=0.677), when controlling for confounders.
CONCLUSIONS: Since counting backward is a mental tracking task, which is a component of executive function, our results suggest a relationship between vitamin D insufficiency and executive dysfunction. Executive dysfunction has been previously associated with fall risks in the elderly, and it could be a possible mediator between vitamin D and falls. Our data suggest that cognition may play a significant role in vitamin D's influence on falls, while motor function may play a lesser role.
Language: en |