Association between the risk and severity of Parkinson’s disease and plasma homocysteine, vitamin B12 and folate levels: a systematic review and meta-analysis

Abstract

BackgroundParkinson’s disease (PD) is recognized as the second most prevalent progressive neurodegenerative disease among the elderly. However, the relationship between PD and plasma homocysteine (Hcy), vitamin B12, and folate has yielded inconsistent results in previous studies. Hence, in order to address this ambiguity, we conducted a meta-analysis to summarize the existing evidence.MethodsSuitable studies published prior to May 2023 were identified by searching PubMed, EMBASE, Medline, Ovid, and Web of Science. The methodological quality of eligible studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). Meta-analysis and publication bias were then performed using R version 4.3.1.ResultsThe results of our meta-analysis, consisting of case–control and cross-sectional studies, showed that PD patients had lower folate and vitamin B12 levels (SMD [95%CI]: −0.30[−0.39, −0.22], p < 0.001 for Vitamin B12; SMD [95%CI]: −0.20 [−0.28, −0.13], p < 0.001 for folate), but a significant higher Hcy level (SMD [95%CI]: 0.86 [0.59, 1.14], p < 0.001) than healthy people. Meanwhile, PD was significantly related to hyperhomocysteinemia (SMD [95%]: 2.02 [1.26, 2.78], p < 0.001) rather than plasma Hcy below 15 μmol/L (SMD [95%]: −0.31 [−0.62, 0.00], p = 0.05). Subgroup analysis revealed associations between the Hcy level of PD patients and region (p = 0.03), age (p = 0.03), levodopa therapy (p = 0.03), Hoehn and Yahr stage (p < 0.001), and cognitive impairment (p < 0.001). However, gender (p = 0.38) and sample size (p = 0.49) were not associated.ConclusionHcy, vitamin B12, and folic acid potentially predict the onset and development of PD. Additionally, multiple factors were linked to Hcy levels in PD patients. Further studies are needed to comprehend their roles in PD.

Cannabinoids: Potential for Modulation and Enhancement When Combined with Vitamin B12 in Case of Neurodegenerative Disorders

“…Vitamin B12 deficiency has been associated with microvascular changes and impaired cerebral blood flow, which may contribute to neuroinflammation and neuronal injury observed in PD. Impaired cerebral perfusion may exacerbate dopaminergic neuron degeneration and motor symptoms associated with PD [ 118 , 119 , 120 ].…”

“…These studies collectively underscore innovative strategies for enhancing drug efficacy and more effectively targeting neurodegenerative and other diseases. Quan et al, 2023 [ 120 ] Quan et al (2023) underline the significant role of vitamin B12 in neurodegenerative processes, with a focus on how fingolimod, a treatment for multiple sclerosis, promotes vitamin B12 homeostasis in the CNS. Fingolimod facilitates this by binding to Transcobalamin 2 (TCN2), creating a complex that increases vitamin B12 availability in astrocytes.…”