Cardiovascular disease linked to brain shrinkage in MS

• A long-term study conducted at the University at Buffalo, NY, USA looked at the potential link between cardiovascular diseases in people with MS and brain lesions and shrinkage (atrophy)
• MRI scans from 194 people with MS, including people with and without cardiovascular diseases, were examined over a five-year period and compared to MRI scans of people without MS
• The study showed that heart disease and high blood pressure (hypertension) were linked to increased loss of whole brain volume and white matter volume in the people with MS Cardiovascular diseases were not linked to increased brain lesions or relapses
• The authors suggest that careful monitoring and treatment of cardiovascular disease in people with MS could be important and could potentially improve overall disease outcomes

Previous studies have shown that the presence of other health conditions in people with MS (known as comorbidities) is associated with worsened disease and poorer long-term outcomes. Conditions such as autoimmune diseases, cardiovascular disease and psychiatric illnesses have all been linked to worse clinical and disability outcomes in MS.

However, there has been some disagreement between different studies as to whether these other health conditions affect brain lesions, brain atrophy (tissue shrinkage) and/or disability. So, researchers at the Buffalo Neuroimaging Analysis Centre at the University at Buffalo, State University of New York, USA set out to investigate this link using a larger group of patients and a comparatively longer follow-up period.

The study, conducted by PhD student Davan Jakimovski, Professor Robert Zivadinoc and their colleagues, was published in the European Journal of Neurology in August.
The study enrolled 194 people with MS and 43 people without neurological disease. The majority of the people with MS had relapsing remitting disease (60%), 15% had clinically isolated syndrome (the very earliest sign of possible MS) and the rest had secondary progressive or primary progressive MS.

MRI scans were taken at the start of the study to measure brain volumes, including whole brain volume, grey matter and white matter volume and the total volume of MS lesions in the brain tissue. Questionnaires were also used to identify the presence of other health conditions. All participants were then followed for an average period of five years, at which point the scans were repeated.

Increased brain atrophy

The researchers found that the participants with MS had greater loss of whole brain volume and white matter volume compared to people without neurological disease and that the people with relapsing MS had a greater white matter loss compared to those with progressive MS, who experienced greater grey matter loss.

When the researchers compared results from the people with MS who had cardiovascular diseases to those who did not, taking into account age, sex, and disease duration, they found that people with MS who also had hypertension or heart disease had a significantly higher loss of whole brain volume and white matter than those who did not have cardiovascular diseases.

Cardiovascular disease was not associated with any differences in brain volume loss in the people without neurological disease, and high blood fat levels (hyperlipidaemia) did not appear to affect brain tissue loss in people with MS.

The researchers did not find any link between cardiovascular diseases and the volume of lesions in the brains of the people with MS and the only characteristic that was linked to a higher number of relapses among the people with MS was a history of smoking.

Heart disease and BMI

The team also looked at whether a combination of other health conditions might also influence brain tissue loss. They found that a combination of heart disease and high body mass index (BMI, a measure of weight relative to height) and having heart disease and a history of smoking were also linked to a greater loss of whole brain and white matter volume over the five-year period.

This five-year study is one of the first to show that high blood pressure and heart disease can contribute to accelerated brain atrophy in people with MS. It confirms and adds to the evidence from previous studies that comorbidities are linked to worse outcomes in people with MS. It also confirms the results of previous studies showing that smoking is associated with worse outcomes in people with MS.

Brain atrophy is a marker of MS disease activity that has been linked more closely to disability outcomes for people with MS than other markers such as relapses and MRI lesions. So, this study adds to the growing evidence that managing other health conditions in people with MS is important to potentially improve long term disease outcomes.

With thanks to MS Research Australia – the lead provider of research summaries on our website.