Objective: To measure blood levels of vitamin B12 and homocysteine (tHcy) in contemporary clinical trial participants and to determine whether these analytes were associated with clinical progression.

Background: Our analysis of baseline serum in the DATATOP study showed geometric mean levels of B12 of 369pg/ml and 9.5µM for tHcy.  We also found associations of low B12 with greater worsening of ambulatory capacity (AC) and of elevated tHcy(>15µM) with greater declines in the MMSE. Since DATATOP was performed in the late 1980’s, before mandatory folic acid fortification in the US, dietary changes may have altered these levels.

Method: We measured B12 and tHcy from baseline and end-of study blood samples from 3 clinical trials of early PD (SURE-PD, STEADY-PDIII, and SURE-PD3) as well as information regarding vitamin supplement use and then tested for associations of analyte levels with annualized changes in clinical rating scales.

Results: Baseline geometric mean B12 levels for these studies ranged from 484-618 pg/ml and for tHcy ranged from 7.4-10 µmol/L. Use of B12-containing supplements ranged from 41-61%, and those taking supplements had higher B12 and lower tHcy. Those who began levodopa, but were not taking B12-supplements, had greater end-of-study tHcy.  Compared to those with tHcy ≤ 15µmol/L, participants combined from STEADY-PDIII and SURE-PD3 with tHcy > 15µmol/L experienced more rapid declines in Montreal Cognitive Assessment scores (0.7 vs 0.2 points/year, p=0.04).  No association of B12 tertiles with AC was observed

Conclusion: In these contemporary trials, B12 levels were higher than for DATATOP, due in large part to increased B12-supplement intake, while tHcy levels were similar.  Like DATATOP, there was greater cognitive decline in those with tHcy>15µM.  While an association of low B12 with greater worsening of ambulatory capacity was not found in this study, the smaller number of subjects with low B12 levels reduced the power to replicate this finding. Further study of tHcy with PD cognitive impairment is warranted, particularly since use of B12 containing supplements appeared to prevent increases in tHcy after starting levodopa.(Presented as poster at the American Academy of Neurology Meeting on April 17, 2024)

« Back to 2024 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/relationships-of-blood-vitamin-b12-and-homocysteine-with-parkinsons-disease-progression-in-3-contemporary-clinical-trials/