“Both are characterized by unstable protein accumulation, lysosomal and mitochondrial dysfunction, and chronic systemic inflammation,” the study authors explained. “Insulin resistance is a hallmark of T2D and may also be an important feature of PD. “
In addition to studies on the association between the two diseases, prior systematic reviews and meta-analyzes have examined whether T2D may contribute to the development of PD risk. Although the findings are controversial, the researchers note that most of these studies employed groups of patients with diabetes, compared to T2D. , with this association also not being explored through modern causal means.
Attempting to further investigate whether T2D can be a predictor of PD, the researchers from Queen Mary University of London (QMUL) conducted a systematic review of 33,408 articles, with 28 observational studies selected for meta -analysis. Each study examined the association of T2D with PD risk and progression and came from 1 of 6 databases: PubMed, Web of Science, Scopus, Ovid, Rxiv, and medRxiv.
Leveraging random mendelian (MR), a method in genetic epidemiology that can be used to follow observational associations for evidence of true causal effects, the researchers then collected summary data from genome-wide association studies. to assess the causal effects of genetic predisposition toward T2D on PD risk and progression.
In the meta-analysis, combined effect estimates showed that T2D was associated with an increased risk of PD (odds ratio [OR], 1.21; 95% CI, 1.07–1.36), MR-supported causal relationship (non-variable stress mechanism) [IVW] NO, 1.08; 95% CI, 1.02-1.14; P. = .010).
In addition, the results show that T2D is associated with faster progression of motor signals (normal mean difference [SMD], 0.55; 95% CI, 0.39–0.72) and cognitive decline (SMD, −0.92; 95% CI, −1.50 to −0.34), although only motor improvement was supported by MR (IVW OR, 1.10; 95% CI, 1.01-1.20; P. = .032).
“This research brings together findings from many other studies to provide conclusive evidence that T2D appears to affect not only PD risk, but also PD progression,” he said. -consociate author Alastair Noyce, MD, senior clinical lecturer in the Neurology Prevention Unit at the Wolfson Institute of Preventive Medicine, QMUL, in a statement.
Addressing the findings of the study, the researchers stated that the analysis did not consider the effect of antidiabetic drugs on PD risk and progression. In particular, prior studies of treatments for the treatment of T2D have been shown to reduce the severity of PD and lower risk of PD.
“T2D treatment could delay PD progression,” the study authors concluded. “Therefore, careful screening for T2D and early treatment of T2D in patients with PD would be appropriate.”
Information
Chohan H, Senkevich K, Patel RK, et al. Type 2 diabetes as a testament to the risk and progression of Parkinson’s disease. Mov Disorder. Published online 8 March 2021. doi: 10.1002 / mds.28551