Multiple Sclerosis Centers of Excellence
Vascular Disease Risk Factors and Multiple Sclerosis
Vijayshree Yadav, MD, MCRP -- Portland, OR
Recent research involving thousands of people with MS suggests that vascular disease risk factors (VDRF) such as obesity, hypertension (high blood pressure), hyperlipidemia (high cholesterol), and diabetes can contribute to the worsening of disability in MS. According to one survey involving more than 8,000 people with MS, nearly 50% of people with MS have at least one VDRF at the time of their MS diagnosis. This article reviews current literature on the relationship between these potentially changeable factors that can affect MS activity and progression.
Among Veterans, VDRF are highly prevalent. Studies suggest that more than 80% of Veterans have at least two VDRF. A current pilot study at the VA in Portland, OR evaluated the prevalence of VDRF in Veterans with MS. The study found that among the 45 enrolled Veterans, 44% had hypertension, 33% had hyperlipidemia, and 11% had diabetes.
Obesity is commonly defined as having a body mass index (BMI) above 30 kg/m2 and overweight individuals as having a BMI between 25 - 29.9 kg/m2. Several studies have suggested higher BMI is associated with greater disability. Importantly, being overweight or obese has been associated with an increase in other comorbidities, with an individual being almost five-times more likely to develop diabetes or hypertension and two-times more likely to develop depression. More comorbidities are also related to decreased quality of life and increased odds of disability.
Hypertension also has a relationship with MS disability. The North American Research Committee on MS (NARCOMS) registry showed increased levels of disability among people with MS with hypertension. People with hypertension had 29% higher risk of early gait disability, 25% higher risk of requiring unilateral assistance (example: cane), and 17% higher risk of requiring bilateral assistance (example: walker) compared to those without hypertension. This registry also showed that people with MS who developed hypertension had a 32% higher risk of developing mild visual disability, 31% higher risk of moderate visual disability, and 16% higher risk of severe visual disability.
Hyperlipidemia has also been associated with MS-related disability and brain imaging (MRI) outcomes. One study looking at blood fat (lipid) levels found that higher low-density lipoprotein (LDL), or “bad” cholesterol, and total cholesterol levels were associated with higher MS disability. Higher high-density lipoprotein (HDL), or “good” cholesterol, was associated with lower inflammatory disease activity on the brain MRI.
It is estimated that 3-8% of people with MS have diabetes mellitus II (DMII), with the highest percentage in North America at 4.1%. In the NARCOMS registry, those with DMII had a 29% higher risk of early gait disability, 28% higher risk of requiring unilateral assistance, and 56% higher risk of requiring bilateral assistance compared to those without DMII, as well as a 35% higher risk of developing mild visual disability, 41% higher risk of moderate visual disability, and 54% higher risk of severe visual disability.
The VA Portland HCS and Oregon Health & Science University MS doctors and scientists are currently conducting a 3-year observational study looking at the progression of MS disability in relation to VDRF. Sixty subjects have been grouped into VDRF positive and VDRF negative. All subjects will have a total of seven study visits consisting of four annual MRI scans. Each study visit will include a neurological exam, physical exam, cognitive tests, and quality of life, nutrition, fatigue, and depression questionnaires. The researchers believe that VDRF may increase disability in MS by slowing blood flow through the gray matter (brain and spinal cord tissue that predominantly contains the nerve cell bodies), decreasing the ability of nerve cells to produce the energy needed for healthy functioning. Using one of the most advanced brain MRI techniques available in the world today, this study will explore abnormalities in vascular function, including blood flow and volume and energy metabolism in the gray matter of the brain. This study may help us develop novel interventions targeting VDRF to slow MS disease progression. The study plans to finish in 2021.
Early identification and management of VDRFs, including lifestyle modification and targeted medical management, may potentially improve outcomes for people with MS by slowing disease activity and disability progression and reducing the risk of other comorbidities that can affect quality of life. While optimizing the management of VDRF will not cure MS, it may provide an additional promising avenue for improving overall health and quality of life.