Vitamin D and caudal primary motor cortex: a magnetic resonance spectroscopy study.
BACKGROUND
Vitamin D is involved in brain physiology and lower-extremity function. We investigated spectroscopy in a cohort of older adults to explore the hypothesis that lower vitamin D status was associated with impaired neuronal function in caudal primary motor cortex (cPMC) measured by proton magnetic resonance spectroscopic imaging.


METHODS
Twenty Caucasian community-dwellers (mean±standard deviation, 74.6±6.2 years; 35.0% female) from the 'Gait and Brain Study' were included in this analysis. Ratio of N-acetyl-aspartate to creatine (NAA/Cr), a marker of neuronal function, was calculated in cPMC. Participants were categorized according to mean NAA/Cr. Lower vitamin D status was defined as serum 25-hydroxyvitamin D (25OHD) concentration <75 nmol/L. Age, gender, number of comorbidities, vascular risk, cognition, gait performance, vitamin D supplements, undernourishment, cPMC thickness, white matter hyperintensities grade, serum parathyroid hormone concentration, and season of evaluation were used as potential confounders.


RESULTS
Compared to participants with high NAA/Cr (n = 11), those with low NAA/Cr (i.e., reduced neuronal function) had lower serum 25OHD concentration (P = 0.044) and more frequently lower vitamin D status (P = 0.038). Lower vitamin D status was cross-sectionally associated with a decrease in NAA/Cr after adjustment for clinical characteristics (β = -0.41, P = 0.047), neuroimaging measures (β = -0.47, P = 0.032) and serum measures (β = -0.45, P = 0.046).


CONCLUSIONS
Lower vitamin D status was associated with reduced neuronal function in cPMC. These novel findings need to be replicated in larger and preferably longitudinal cohorts. They contribute to explain the pathophysiology of gait disorders in older adults with lower vitamin D status, and provide a scientific base for vitamin D replacement trials.
Gait and Brain Lab, Lawson Health Research Institute, Parkwood Hospital, The University of Western Ontario, London, Ontario, Canada ; Division of Geriatric Medicine, University Hospital; Memory Clinic; UPRES EA 4638, University of Angers, Angers, France ; Robarts Research Institute, the University of Western Ontario, London, Ontario, Canada.
Cedric
C
Annweiler
Division of Geriatric Medicine, University Hospital; Memory Clinic; UPRES EA 4638, University of Angers, Angers, France.
Olivier
O
Beauchet
Robarts Research Institute, the University of Western Ontario, London, Ontario, Canada.
Robert
R
Bartha
Department of Clinical Neurological Sciences, University Hospital, the University of Western Ontario, London, Ontario, Canada.
Vladimir
V
Hachinski
Gait and Brain Lab, Lawson Health Research Institute, Parkwood Hospital, The University of Western Ontario, London, Ontario, Canada.
Manuel
M
Montero-Odasso
D000368:Aged; D000369:Aged, 80 and over; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D003071:Cognition / Q000502:physiology; D015331:Cohort Studies; D003401:Creatine / Q000378:metabolism; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D009044:Motor Cortex / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D015999:Multivariate Analysis; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D010281:Parathyroid Hormone / Q000097:blood; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D010281:Parathyroid Hormone; D014807:Vitamin D; D001224:Aspartic Acid; C000179:N-acetylaspartate; C104450:25-hydroxyvitamin D; D003401:Creatine