Following on from Alastair's post about links between metabolic syndrome and risk of Parkinson's disease, I've been reading this study which looks at a concept related to the metabolic syndrome - vascular risk. Here the authors are interested in how risk factors such as high blood pressure, diabetes and body mass affect people in the early stages of Parkinson's and particularly how they relate to the subtle problems with thinking and memory.
They studied 140 people with early-stage Parkinsons and around 60 healthy people of the same age, who were assessed for vascular risk factors and performance on tests of thinking and memory and followed up for 4 years. These patients and healthy subjects all had MRI scans to look for subtle signs of damage to the brain due to problems with blood vessels.
They looked at links between factors such as diabetes and blood pressure, scores on cognitive tests and the number of areas of abnormalities on MRI. Their first important finding was no difference between areas of abnormality on MRI scan between Parkinson's patients and healthy participants. However, in Parkinson's disease but not healthy people, MRI abnormalities were associated with poor performance on memory tests. Furthermore, the risk score was associated with a deterioration in an overall test of mental processes over time.
There are some issues with this study - in traditional statistics, we set a standard of certainty, which allows for a small amount of error. The more experiments you do, the more chance you will make an error and find a positive result by chance. This study looks at many associations, increasing the risk that some results may not be true.
However, it's particularly important to study these associations due to the fact that factors such as blood pressure and diabetes are treatable with current medications. If these factors play any significant role in memory problems in Parkinson's, we will need to look for them and aggressively treat them from early in the disease. We need to build up an evidence basis for this, looking in more detail for example at the level of blood pressure over which treatment will improve outcomes. In the meantime, it's a good reminder for physicians and patients of the multiple additional potential benefits of managing blood pressure, diabetes and weight.
- anna
https://www.ncbi.nlm.nih.gov/pubmed/30169897?log$=activity
They studied 140 people with early-stage Parkinsons and around 60 healthy people of the same age, who were assessed for vascular risk factors and performance on tests of thinking and memory and followed up for 4 years. These patients and healthy subjects all had MRI scans to look for subtle signs of damage to the brain due to problems with blood vessels.
They looked at links between factors such as diabetes and blood pressure, scores on cognitive tests and the number of areas of abnormalities on MRI. Their first important finding was no difference between areas of abnormality on MRI scan between Parkinson's patients and healthy participants. However, in Parkinson's disease but not healthy people, MRI abnormalities were associated with poor performance on memory tests. Furthermore, the risk score was associated with a deterioration in an overall test of mental processes over time.
There are some issues with this study - in traditional statistics, we set a standard of certainty, which allows for a small amount of error. The more experiments you do, the more chance you will make an error and find a positive result by chance. This study looks at many associations, increasing the risk that some results may not be true.
However, it's particularly important to study these associations due to the fact that factors such as blood pressure and diabetes are treatable with current medications. If these factors play any significant role in memory problems in Parkinson's, we will need to look for them and aggressively treat them from early in the disease. We need to build up an evidence basis for this, looking in more detail for example at the level of blood pressure over which treatment will improve outcomes. In the meantime, it's a good reminder for physicians and patients of the multiple additional potential benefits of managing blood pressure, diabetes and weight.
- anna
https://www.ncbi.nlm.nih.gov/pubmed/30169897?log$=activity
Eur J Neurol. 2018 Aug 31. doi: 10.1111/ene.13797. [Epub ahead of print]
Modifiable Vascular Risk Factors, White Matter Disease, and Cognition in Early Parkinson's Disease
Chahine LM, Dos Santos C, Fullard M, Scordia S, Weintraub D, Erus G, Rosenthal L, Davatzikos C, McMillan CT.
Dementia in Parkinson's Disease (PD) is common and disabling. Identification of modifiable risk factors for it is essential. Vascular risk factors may be associated with cognitive decline in early PD. Biomarkers that serve as surrogates of the long-term effect of vascular risk factors on PD are needed. To that end, we aimed to quantitate white matter hyperintensities in early PD, measure associations with vascular risk factors, and examine relationships between white matter hyperintensities and longitudinal cognition.
Participants in the Parkinson Progression Markers Initiative study (141 PD patients, 63 healthy controls) with adequate baseline structural brain MRIs were included. Hypertension and diabetes history, and body mass index, were combined to create a vascular risk score. White matter hyperintensities were quantitated via automated methods. Cognition was assessed annually with a comprehensive test battery.
Vascular risk score was associated with white matter hyperintensities for total brain (β=0.210;p=0.021), total white matter (β=0.214;p=0.013), frontal (β=0.220;p=0.002) and temporal (β=0.212;p=0.002) regions. Annual rate of change in global cognition was greater in those with higher vascular risk score (β=-0.040;p=0.008) and greater white matter hyperintensities (β=-0.029;p=0.049). Higher temporal white matter hyperintensity burden was associated with great decline over time in verbal memory (β=-0.034;p=0.031).
In early PD, modifiable vascular risk factors are associated with white matter hyperintensities on brain MRI. Temporal white matter hyperintensity burden predicts decline in verbal memory. White matter hyperintensities may serve as a surrogate marker for the effect of vascular risk factors on cognitive abilities in PD. This article is protected by copyright. All rights reserved.
Participants in the Parkinson Progression Markers Initiative study (141 PD patients, 63 healthy controls) with adequate baseline structural brain MRIs were included. Hypertension and diabetes history, and body mass index, were combined to create a vascular risk score. White matter hyperintensities were quantitated via automated methods. Cognition was assessed annually with a comprehensive test battery.
Vascular risk score was associated with white matter hyperintensities for total brain (β=0.210;p=0.021), total white matter (β=0.214;p=0.013), frontal (β=0.220;p=0.002) and temporal (β=0.212;p=0.002) regions. Annual rate of change in global cognition was greater in those with higher vascular risk score (β=-0.040;p=0.008) and greater white matter hyperintensities (β=-0.029;p=0.049). Higher temporal white matter hyperintensity burden was associated with great decline over time in verbal memory (β=-0.034;p=0.031).
In early PD, modifiable vascular risk factors are associated with white matter hyperintensities on brain MRI. Temporal white matter hyperintensity burden predicts decline in verbal memory. White matter hyperintensities may serve as a surrogate marker for the effect of vascular risk factors on cognitive abilities in PD. This article is protected by copyright. All rights reserved.
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