The Relationship between Nutrient Status and Cognitive Performance in Persons with Parkinson's Disease

OBJECTIVE: To determine the relationship between plasma markers of nutrient status and cognitive function in persons with Parkinson’s disease.BACKGROUND: Cross sectional data suggests that higher vitamin D levels may be related to better performance in some cognitive domains in persons with PD. Elevated homocysteine and low omega-3 poly-unsaturated fatty acids (PUFAs) have also been associated with cognitive decline. We hypothesized that the combination of these measurements would be a greater predictor of cognitive impairment than individual measurements.DESIGN/METHODS: This is an add-on study to a longitudinal study following memory function in persons with Parkinson’s disease. 294 subjects with PD were examined. Cut off levels for each measure were as follows: Deficient vitamin D3 u003e30 ng/ml; elevated homocysteine u003c14 ng/ml; deficient omega-3 - EPA+DHA u003c5[percnt] total PUFA weight. Cognitive measures included measures of global function (MMSE, MOCA), verbal memory (Hopkins Verbal Learning Test), verbal fluency (animals, vegetables, FAS words), attention (digit-symbol substitution, line orientation) and executive function (trails test, letter-number sequencing) were administered. Ordinary least-squares regression assessed mean differences in cognition between deficiency groups after correcting for age.RESULTS: Nutrient deficiencies were found as follows: fully replete - 49; 1 deficiency - 114; 2 deficiencies - 98; fully deficient - 39. Compared to fully replete subjects, fully deficient subjects showed significantly poorer cognitive ability across a number of tests including digit-symbol substitution (p=0.049), vegetable fluency (pu003c0.018), immediate verbal recall (p=0.011), and delayed verbal recall (p=0.023). Subjects deficient in at least two biomarkers also showed reduced performance in immediate recall compared to fully replete subjects (p=0.034).CONCLUSIONS: These results indicate PD patients whose serum levels of vitamin D3, homocysteine and omega-3 PUFAs are outside normal ranges exhibit poorer cognitive ability across a handful of domains, especially with respect to verbal performance. Disclosure: Dr. Hiller has nothing to disclose. Dr. Murchison has received research support from NINDS. Dr. Cholerton has nothing to disclose. Dr. Hu has nothing to disclose. Dr. Zabetian has nothing to disclose. Dr. Leverenz has received personal compensation for activities with Axovant, GE Healthcare, Navidea Biopharmaceuticals, Piramal Healthcare, and Teva CNS as a consultant. Dr. Chung has received personal compensation in an editorial capacity for Med-IQ. Dr. Montine has nothing to disclose. Dr. Carney has nothing to disclose. Dr. Quinn has received personal compensation for activities with Novartis as a speaker.