- A new study published in Neurology, the Official Journal of the American Academy of Neurology, showed that people with multiple sclerosis (MS) and depression had about a 5.4 times increased risk of death from all causes compared to people without MS and depression.
- People with MS with and without depression also had an increased risk of vascular diseases, such as heart attack and stroke.
- The study findings emphasize the importance of identifying and treating depression and other cardiovascular (CV) risk factors in people with MS.
Nearly 1 million people in the United States have MS, a central nervous system disease with a variable and sometimes disabling course. Women are three times more likely to develop MS than men, and people typically receive a diagnosis between 20-50 years of age.
Scientists believe MS is an autoimmune disease where a person’s body attacks the myelin sheath (the covering surrounding the nerves), resulting in abnormal conduction of electrical impulses through the nerves in the brain and spinal cord.
People with MS may experience various symptoms, including altered vision, muscle weakness, incoordination, numbness, pain, trouble with memory or focus, tremors, and depression.
The paper in Neurology quotes previous studies showing that people without MS but with depression have a 30% increased risk of developing vascular disease and a 70% greater risk of death from all causes.
This prompted researchers from the Imperial College of London, the University College London Queen Square Institute of Neurology in the United Kingdom, and the Max Rady College of Medicine University of Manitoba, CA, to conduct a study.
In an interview with MNT, co-author and study researcher Dr. Raffaele Palladino, MD, Ph.D. in the Department of Primary Care and Public Health, Imperial College of London, explained: “Depression is the most frequent comorbidity in people with MS, affecting more than 20% of them.”
“Considering that depression is associated with poorer health behaviors (diet, physical activity) and vascular risk management, we wanted to assess whether the association between depression, vascular disease, and mortality differs in people with MS as compared with [the] general population.”
The retrospective study examined medical records of 12,251 people with MS and 72,572 people without MS (matched control group) from England who featured in the Clinical Research Datalink database between January 1, 1987, and September 30, 2018.
For the study, researchers stratified participants into four groups: the control group without depression, the control group with depression, MS without depression, and MS with depression. The study followed participants until an event occurred or the end of the study period, whichever came first.
The outcomes that the study measured included:
- acute coronary syndrome
- cerebrovascular disease
- combination of acute coronary syndrome, cerebrovascular disease, and peripheral arterial disease
- CV mortality
- all-cause mortality
Twenty-one percent of participants with MS and 9% of control groups had depression at baseline. People with depression tended to be younger and female.
Over 10 years, people with MS had an increased risk of vascular disease with and without depression versus matched controls without depression. The vascular disease risk was about 1.5 fold for people with MS without depression and 3.3 fold for people with MS and depression.
Over the same decade and compared to the control group without depression, participants in the control group with depression had 1.8 times increased risk for all-cause mortality. The risk for all-cause mortality for those with MS without depression was 3.9 times higher and 5.4 times greater for those with MS and depression.
Researchers also observed sex-specific differences in the results. Women with depression and MS had 2.62 times the risk of CV disease death than controls without depression. Whereas for men with MS and depression, there was no increased risk.
Strengths of the study include the study’s large sample size, study design, long duration of follow-up, and use of sensitivity and statistical analyses to control for potential
Limitations of the study include missing data leading to the exclusion of analysis of body mass index as a factor and potential miscoding or misclassification of collected data.
Dr. Barbara Giesser, MD, neurologist, MS specialist at Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, CA, an expert who was not involved in the study, commented on the need for additional studies for MNT.
“This paper [showed] a synergistic association between depression and CV disease and overall mortality in the MS population, [with a greater increase in] mortality from atherosclerotic vessel disease in women with MS and depression [than] men.”
“You certainly want to see if treating depression and atherosclerotic vascular disease in people with MS lowers their overall mortality and […] see if treating the depression lowers the risk of atherosclerotic vessel disease,” she said, adding:
“The take-home message is that these are risk factors outside of the direct […] neurologic impact of MS that need to be identified and treated. Depression certainly should be screened for and addressed, as well as risk factors for vascular disease such as diabetes, hypertension, and hyperlipidemia.”