J Parkinsons Dis. 2013 Sep 30.
Peterson AL, Murchison C, Zabetian C, Leverenz J, Watson GS, Montine T, Carney N, Bowman GL, Edwards K, Quinn JF.
Portland, OR, USA Oregon Health and Sciences University.
Background: Research in recent years has suggested a role of vitamin D in the central nervous system. The final converting enzyme and the vitamin D receptor are found throughout the human brain. From animal studies vitamin D appears important in neurodevelopment, up-regulation of neurotrophic factors, stabilization of mitochondrial function, and antioxidation.
Objective: To examine the relationship between serum vitamin D and neuropsychiatric function in persons with Parkinson's disease (PD).
Methods: This is an add-on study to a longitudinal study following neuropsychiatric function in persons with PD. Baseline neuropsychiatric performance and serum 25-hydroxyvitamin D were examined for 286 participants with PD. Measures of
- global cognitive function (MMSE, MOCA, Mattis Dementia Scale),
- verbal memory (Hopkins Verbal Learning Test),
- fluency (animals, vegetables, and FAS words),
- visuospatial function (Benton Line Orientation),
- executive function (Trails Making Test and Digit-Symbol Substitution),
- PD severity (Hoehn & Yahr and Unified Parkinson's Disease Rating Scale) and
- depression (Geriatric Depression Scale (GDS))
were administered. Multivariate linear regression assessed the association between vitamin D concentration and neuropsychiatric function, in the entire cohort as well as the non-demented and demented subsets.
Results: Using a multivariate model, higher vitamin D concentrations were associated with better performance on numerous neuropsychiatric tests in the non-demented subset of the cohort. Significant associations were specifically found between vitamin D concentration and verbal fluency and verbal memory (t = 4.31, p < 0.001 and t = 3.04, p = 0.0083). Vitamin D concentrations also correlated with depression scores (t = -3.08, p = 0.0083) in the non-demented subset.
Conclusions: Higher plasma vitamin D is associated with better cognition and better mood in this sample of PD patients without dementia.
Determination of causation will require a vitamin D intervention study.
Note: It appears that if the data were spline fitted, rather than a straight line, that the curve might have peaked around 50 ng
- Overview Parkinson's and Vitamin D
- Increased word fluency associated with higher levels of vitamin D (40 ng and higher) – Dec 2015
- Parkinson's disease stabilized with just 1200 IU of vitamin D – RCT May 2013
- Higher vitamin D levels associated with better cognition and mood in PD patients Medical Press, Jan 2014, comment on this study