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Managing MS during pregnancy

Opinion on how MS impacts pregnancy is based largely on data that predate the current era of active treatment and the newer generation of disease-modifying therapies (DMTs). In this section I have therefore addressed many of the important issues that women who are considering pregnancy need to understand, including:

  • the effect of pregnancy on the course of MS
  • how to manage relapse during pregnancy
  • the role of naturally occurring interferon-beta and its possible implications for women with MS taking therapeutic interferon-beta
  • management of MS symptoms and morning sickness during pregnancy
  • the crucial issue of DMT safety and possible teratogenic effects on the developing foetus.

Will pregnancy affect the course of my MS?

Yes, pregnancy effects on MS have been observed at a group level, though it is difficult to notice changes in individuals. It is well known that MS attack rates drop during the second and third trimesters of pregnancy and relapses rebound again in the first 6 months after delivery. However, only a minority of women with MS have post-partum relapses. Breastfeeding may blunt the post-partum rebound, but this is not absolute. Therefore, most neurologists now recommend starting or restarting DMTs soon after delivery to try and prevent post-partum relapses.

At a population level, the more children you have, the better your overall prognosis. This effect is small and is based on studies done in the pre-DMT era. It may be due to the immunological effects of pregnancy that work like a DMT in MS. Immunologists have tried to understand this phenomenon in the hope of developing treatments for MS that mimic the pregnancy state.

How is a relapse managed during pregnancy?

In the event of having a relapse during pregnancy, a short course of high-dose corticosteroids can be considered. However, I limit using steroids to disabling and/or severe relapses, especially early in the first trimester, as there is a small risk of orofacial abnormalities (cleft lip and palate) and reduced birth weight from exposure of the developing foetus to high-dose steroids. There is also a risk of precipitating gestational diabetes in women receiving high doses of steroids during pregnancy. In the rare situation of a severe relapse unresponsive to high-dose steroids, plasma exchange may need to be considered.

Could neutralising antibodies to therapeutic interferon-beta affect my baby?

Naturally occurring interferon-beta is a cytokine (cell-signalling agent) produced by the body to help fight infections. As there is only one human interferon-beta, antibodies to therapeutic interferon-beta (IFN-beta) will neutralise the body’s own natural interferon-beta. If you are taking IFN-beta for your MS, there is thus a theoretical risk that neutralising antibodies (NABs) to the DMT might cross the placenta and affect the role of human interferon-beta in foetal development.

Interferon-beta is important for innate immunity and neutralising your own interferon-beta may put you at risk of getting viral infections. Interferon-beta also plays a role in foetal bone development, but the placenta does not mature in relation to immunoglobulin transfer until near the end of the second trimester of pregnancy, so it is unlikely that sufficient NABs cross the blood ̶ placental barrier to affect foetal bone development. However, in the third trimester, NABs will cross over the placenta into the foetal circulation and may impact the baby’s innate immunity. Despite these theoretical concerns, there is no indication from published data to support these potential adverse effects of NABs on IFN-beta.

If I fall pregnant while on a DMT, will this affect the baby?

This depends on which DMT you are taking and what you mean by ‘affecting the baby’. We worry most about teratogenic effects, which describe congenital malformations. Teriflunomide, S1P modulators and cladribine are generally classified as drugs that may be teratogenic, and hence precautions need to be taken so as not to fall pregnant on these agents. Foetal malformations usually occur very early in foetal development, often before the woman knows she is pregnant; therefore, it is difficult to do anything about it once foetal exposure occurs. Despite this, even for women who are on these agents and fall pregnant, we don’t automatically recommend termination of pregnancy. We refer them to the high-risk pregnancy clinic to discuss the options with an obstetrician. Many women continue their pregnancies with an uneventful outcome and a normal baby. On the other hand, some women choose the option of terminating their pregnancy.

A large amount of data from MS pregnancy registries and post-marketing surveillance indicates no increased risk of major congenital anomalies or spontaneous abortions (miscarriages) after exposure to interferon-beta or glatiramer acetate. Most neurologists are, therefore, comfortable with their female patients falling pregnant on these agents, continuing the treatment through pregnancy and then breastfeeding their babies.

Fumarates (dimethyl fumarate [Tecfidera], diroximel fumarate [Vumerity]) are not teratogenic and are unlikely to have a negative impact on pregnancy outcomes. We need more data from registries and post-marketing surveillance before we can be confident that the fumarates are safe during pregnancy. However, these agents are prodrugs and converted to monomethyl fumarate, which is part of our metabolism, so it is very unlikely that the fumarates will cause problems. I don’t have an issue with women falling pregnant on the fumarates and continuing them through pregnancy, but there is conflicting advice about this.

Should I continue taking drugs for my MS symptoms during pregnancy?

Yes and no. It depends on what the medications are for and whether they are safe during pregnancy. Ideally, you should wean off any symptomatic therapies or at least change to alternative medications that are safe to take during pregnancy. It is important to try and plan your pregnancy and if necessary be referred to a special medical pregnancy clinic so that these issues can be addressed. Many women with MS find that their MS-related symptoms improve during pregnancy, and they can do without symptomatic therapies. However, unless you are prepared to wean yourself off symptomatic therapies you won’t know.

Physical therapies should be continued during pregnancy. One could argue that everyone with MS should be physically active and do pelvic floor exercises. Pregnancy and childbirth may impact bladder and bowel function, so it is important to see a pelvic floor therapist to start pelvic floor exercises. The latter are taught to women in antenatal classes.

How do you treat morning sickness or hyperemesis gravidarum during pregnancy?

Treating morning sickness or hyperemesis gravidarum is no different in women with MS than in the general population. It involves hydration, vitamin supplements (in particular, thiamine) and the judicious use of antiemetics (for example, cyclizine, prochlorperazine, promethazine, chlorpromazine, metoclopramide and domperidone). If the vomiting extends into the second trimester, ondansetron can be used. In very severe cases of morning sickness, steroids may be required; for example, hydrocortisone 100 mg twice daily can be converted to prednisolone 40 ̶ 50 mg daily by mouth, which can then be tapered to the lowest level that still controls symptoms. For patients taking a fumarate, try and take your medication later in the morning when you are less likely to vomit.

What dose of vitamin D do you advise during pregnancy?

During pregnancy vitamin D requirements are increased and I recommend doubling the dose for supplementation from 4,000 IU of vitamin D3 to 8,000 IU per day. At the same time, women who are pregnant should be on iron and folate supplements that should ideally be started before falling pregnant.

References

Krysko KM et al. Treatment of women with multiple sclerosis planning pregnancy. Curr Treat Options Neurol 2021;23:11.

Other articles in this series on Pregnancy and childbirth
Planning for pregnancy
Preparing to give birth
Breastfeeding if you are on a DMT
Concerns about parenting

Concerns about parenting

Being disabled or unemployed because of MS does not mean you cannot be a good parent. Here I cover some of these practical considerations as well as the steps you can take to reduce the potential risk of your child developing MS.

Can I be a good parent if I become disabled from my MS?

This is difficult to answer and depends on how disabled you are, the nature of your disabilities and whether you have support. For example, some patients who are wheelchair users, or close to being wheelchair users, when they give birth manage to nurse and look after their children. On the other hand, some patients with cerebellar problems find it very difficult to bathe, change and feed their babies due to poor coordination and tremor. If you have advanced MS, the decision to start or extend your family needs to be discussed with your partner. If necessary, ask an occupational therapist to assess you and discuss all the issues relevant to you becoming a parent. Disability per se is not a reason not to have children, but it does raise important issues that need careful consideration. The decision to have children needs to be taken by you and not by your HCP.

If I become disabled or unemployed because of MS, will I be able to support my children?

This is another difficult question, and the answer depends on your circumstances. In the modern era having children and supporting them is expensive, but most high-income countries have social safety nets to protect you and your family in times of adversity. We now have effective DMTs that prevent or delay disability, so deciding to have children is easier than it was in the pre-DMT era.

What is the risk of my children getting MS?

MS is not a genetic disease in the Mendelian sense that you pass on to your children with a well-defined inheritance pattern. However, there are genetic factors that increase your risk of getting MS. In high-prevalence countries such as the UK, the lifetime chances of a woman developing MS is about 1 in 375 ̶ 400; for a man, it is close to 1 in 750 ̶ 800. However, for a daughter whose mother has MS, the risk is close to 1 in 40, and for a son, it is lower than 1 in 80. In some studies, the latter risk is no higher than the background rate. If the father has MS, the risk of his daughter developing MS is about half the risk of mother ̶ daughter pairing, i.e. 1 in 70. For a son of a father with MS, the risk is likely lower than this, but the results across studies are inconsistent.  

Can I prevent my children from getting MS?

Based on the known and modifiable risk factors for MS, you should try and keep your children vitamin D replete. To do this, you will likely need to supplement your children’s vitamin D intake as follows:

  • for children less than 2 years of age, 600 IU per day
  • for children 2 ̶ 10 years of age 2,000 IU per day
  • for children above 10 years of age, 4,000 IU vitamin D3 per day (the same dose we recommend for adults).

Other modifiable risk factors are childhood and adolescent obesity and smoking. We estimate that about 15 ̶ 20% of new or incident new cases could potentially be prevented by eliminating obesity and smoking in the general population. I must stress that these suggested interventions are based on studies that show associations between the risk factors and MS but may not necessarily be cause and effect. I should also point out that most people with all the risk factors for MS will not get the disease. This implies that the development of MS involves other random factors, or bad luck, that can’t necessarily be modified.

The issues raised above show you how complex the management of MS has become, which is why there is a push for people with MS to be managed in specialist MS units.

References

Krysko KM et al. Treatment of women with multiple sclerosis planning pregnancy. Curr Treat Options Neurol 2021;23:11.

Other articles in this series on Pregnancy and childbirth
Planning for pregnancy
Managing MS during pregnancy
Preparing to give birth
Breastfeeding if you are on a DMT

What is multiple sclerosis?

This is the first of a series of basic lessons to help you understand multiple sclerosis (MS).

Key points

  • MS is an autoimmune disease in which the immune system attacks the central nervous system.
  • Its exact cause is unknown; some contributory environmental factors are outlined.
  • Common manifestations of MS include lesions, relapses and intermittent symptoms, which often worsen with fatigue.
  • Early treatment is important to help prevent the damage that occurs with MS.

Multiple sclerosis (MS) is an organ-specific autoimmune disease. Autoimmune simply means that the immune system, whose primary role is to fight infections and cancers, goes awry and attacks itself. Organ-specific means that a disease is limited to one organ. So, in the case of MS, the immune system attacks the central nervous system (CNS), which consists of the brain, spinal cord and optic nerves.

Every organ in the body has its specific autoimmune disease. For example:

  • joints: rheumatoid arthritis
  • skin: psoriasis 
  • insulin-producing cells of the pancreas: type 1 diabetes
  • intestines: inflammatory bowel disease
  • kidneys: autoimmune nephritis (interstitial or glomerulonephritis).

The cause of MS

At present, the exact cause of MS is unproven. MS is a complex disease that occurs due to the environment’s interaction with inherited or genetic factors.1 Some of the main environmental factors are:

  • low vitamin D levels or a lack of sunshine
  • smoking 
  • Epstein–Barr virus (EBV), the virus that causes infectious mononucleosis (glandular fever) 
  • obesity, particularly in adolescence.

What we don’t know is how these genetic and environmental factors interact to cause MS. There are many genetic variants that predispose someone to get MS, but only a minority of people who have these variants will get the disease. Similarly, only a minority of people exposed to environmental risk factors get the disease.

Mechanisms that underlie the common manifestations of MS

Lesions

MS is characterised by inflammatory lesions – areas of damage or scarring (sclerosis) in the CNS – that come and go. The clinical manifestations of MS depend on where these inflammatory lesions occur. If, for example, a lesion involves the optic nerve, it will cause impaired vision; if it involves the brain stem, it causes double vision, vertigo or unsteadiness of gait; a spinal cord lesion leads to loss of feeling, limb weakness or bladder and bowel problems.  

Relapses

A new MS lesion in a site that is eloquent will cause symptoms and neurological signs; if these last for at least a day, they are called an attack or a relapse. If a lesion occurs in a site not associated with overt symptoms, this is often referred to as a subclinical or asymptomatic relapse. Subclinical relapses can be detected using magnetic resonance imaging (MRI). It is said that for every clinical attack there are 10 or more sub-clinical attacks (new MRI lesions).2 

Damage frequently occurs at the site of MS lesions. The inflammation strips the myelin covering the nerve processes and may cut through axons. Axons are the nerve processes that transmit electrical impulses or signals. When the axons are stripped of their myelin sheath, and/or are cut, they can’t transmit electrical signals. This causes loss of function, which manifests with specific symptoms.

Demyelination: loss of the myelin sheath that insulates nerves, leading to disruption of electrical signals. Image courtesy of Timonina/shutterstock.com

Intermittent symptoms

Surviving axons that pass through the lesion are able to recover function, by synthesising and distributing so-called ion channels across the demyelinated segment or by being remyelinated. Both these processes are not perfect. For example, the new sodium channels may not function normally, so they sometimes fire spontaneously. The spontaneous firing of axons may cause positive symptoms, for example, pins and needles, pain or spasms. The new myelin is typically thinner and shorter than normal and is temperature, fatigue and stretch sensitive. 

Stretch sensitivity

If someone with MS has a lesion in their spinal cord, electric shock-like sensations may occur when they stretch the spinal cord by bending or flexing their neck; this is known as Lhermitte’s sign.  

Temperature sensitivity

Recurrent symptoms may occur when body temperature rises, for example following fever, exercise or a hot bath. The MS symptoms (which may vary among individuals) disappear when the fever resolves or the body cools down. The temperature sensitivity is often referred to as Uhtoff’s phenomenon

Fatigue

Symptoms tend to worsen with physical and/or mental fatigue; for example, someone with MS may begin dragging a leg or dropping their foot after 20–30 minutes of walking. This is because the transmission in the functioning nerves, which have been previously damaged, begins to fail. This failure may be related to a lack of energy and/or to temperature changes that occur with exercise. 

Worsening MS (also called progressive MS)

If the axons, or nerve processes, above and below an MS lesion die off, the surviving axons may sprout to take over the function of the axons below the lesion. This puts an unnecessary strain on the surviving axons, which makes them vulnerable to die off in the future. A reduction in the number of nerves in a neuronal system reduces the neurological reserve of that system, making it more vulnerable to future attacks. In other words, the ability to recover from future attacks is reduced, and the neuronal pathway is susceptible to delayed degeneration and premature ageing. Clearly, if no treatment is given and focal inflammatory lesions continue to come and go, this will cause worsening of the disease. If enough damage is allowed to accrue, even switching off new inflammatory lesions may not prevent the so-called delayed neurodegeneration. This is why one of the primary principles of managing MS is early treatment to prevent damage from occurring in the first place. We have also discovered that the neuronal systems with the longest nerve fibres, in particular the bladder and legs, are much more susceptible to damage. We think this is simply because the longest pathways provide the greatest scope to be hit by multiple MS lesions.

Ageing and MS

As we get older our nervous systems degenerate. If we live long enough, we will all develop age-related neurological problems, such as unsteadiness of gait, loss of memory, reduced vision, loss of hearing, and poor coordination. 

What protects people with MS from becoming disabled and developing age-related neurodegeneration are brain reserve and cognitive reserve. Brain reserve is simply the size of your brain or the number of nerve cells you have. Cognitive reserve, in comparison, relates to how well these nerves function; it is associated with your level of education and how well you enrich your life by using your brain. From about 35 years of age, our brains start to shrink. In MS, this brain shrinkage is in general much greater than normal, and the resulting reduction in brain and cognitive reserve almost certainly primes the nervous system to age earlier. This is one of the reasons why people with MS continue to develop worsening disability later in the course of their disease. This insight is one of the main reasons why we promote early effective treatment of MS to protect and maintain brain and cognitive reserves.  


References

  1. Olsson T, et al. Interactions between genetic, lifestyle and environmental risk factors for multiple sclerosis. Nat Rev Neurol 2017;13:25–36.
  2. Gafson A, et al. The diagnostic criteria for multiple sclerosis: From Charcot to McDonald. Mult Scler Relat Disord 2012;1:9–14

What prognostic group do I fall into?

Having some idea of how bad your MS is, or not, will allow you to discuss important issues with your neurologist so that you can make an informed decision about your MS treatment.

Key points

  • It is hard to predict the disease course of MS accurately for an individual.
  • Population data allow us to define three broad prognostic MS categories: good, indeterminate or poor.
  • Given sufficient time, most people with MS will do badly without treatment.
  • Factors linked to poor prognosis in untreated people with MS are listed.
  • The wide use of disease-modifying therapies is changing the natural history of MS for the better.
  • Adopting a healthy lifestyle, in parallel with appropriate treatment, can help to improve outcomes.  

Predicting MS outcomes: an imperfect science

We can’t predict the prognosis of an individual person with MS very accurately. So don’t let your neurologist mislead you if he or she says you are likely to have benign MS. ‘Benign MS’ is a relative term and can only be used retrospectively once you have had MS for many years or decades. In the era before disease-modifying treatments (DMTs), most people with MS would eventually become disabled, which is why I prefer not to use the term benign MS to predict outcomes. I now use it as a treatment aim, because we want all people with MS to have benign disease.

Three broad prognostic categories

Applying population data to place an individual into a broad prognostic group is often helpful. It allows you to frame your disease in terms of potential outcomes and may help you balance the risks of some treatments against the potential impact of MS later in your life. Predicting outcomes in MS is comparable to an actuary working in the insurance industry; we try to give you an average prognosis with a wide range of possibilities or errors. For this reason, I try to keep it simple and classify people with MS into three prognostic categories: poor, indeterminate, or good. Poor in this context means that if you leave MS to its own devices and let it run its natural course, the average person in this category will do badly.

Most people with a predicted poor prognosis will do badly without treatment for their MS.

Given sufficient time, most people with MS will deteriorate without treatment. This is why I actively promote treatment based on the scientific rationale that preventing damage now will protect your brain reserve and cognitive reserve and improve your long-term outcome. This is the philosophy behind the MS Brain Health initiative and the report Brain health: time matters in multiple sclerosis,1 which everyone with MS should take time to read. 

Factors linked to poor prognosis

Below is a list of factors that have been linked to poor prognosis in people who have not received a DMT. If you have fewer than five of these factors, you are likely to have a good outcome. In comparison, people with ten or more of these factors fall into the poor prognostic group. Most people with MS fall into the intermediate (indeterminate) prognostic group, with 5–10 of these factors. Some of these baseline factors are modifiable,2,3 so you can make the effort to help improve your own prognosis

Please note that the factors listed here only apply to people with MS who are untreated.  It is clear that DMTs are changing the outcome of MS.

  1. Older age of onset (greater than 40 years).
  2. Male sex.
  3. Multifocal onset – more than one site in the nervous system involved with the initial attack.
  4. Efferent or effector system is affected early – that is, the motor (power), cerebellar (balance and coordination) or bladder and bowel functions.  
  5. Partial or no recovery from initial relapses – do you have residual deficits from your initial attacks?
  6. A high relapse rate in the first 2 years – that is, more than two relapses. 
  7. Early disability – an Expanded Disability Status Scale (EDSS) score > 3.0 within 5 years of symptom onset indicates a poor prognosis. You can calculate your EDSS using an online calculator (web-EDSS calculator).
  8. Abnormal magnetic resonance imaging (MRI) scan with large lesion load – more than nine T2 lesions (white blobs) on the baseline MRI.
  9. Active or enhancing lesions on your baseline (initial) MRIenhancing lesions imply that the lesions are new and actively inflamed.
  10. Posterior fossa lesions on the MRI – these refer to lesions in the back of the brain that involve the brainstem and cerebellum.
  11. Lesions in the spinal cord on MRI.
  12. Obvious early brain atrophy on MRI – brain atrophy refers to premature shrinkage of the brain over and above what you would expect for your age. This information is unlikely to be available to you because neuroradiologists often do not measure or comment on it. 
  13. Retinal thinning on optic coherence tomography (OCT) – people with MS who have lost a lot of retinal nerve fibres do worse than people with a normal retina. Yes, the eye is truly a window into what is happening in the brain of someone with MS. 
  14. Abnormal cerebrospinal fluid – positive immunoglobulin (Ig) bands (known as oligoclonal bands, OCBs) in the spinal fluid.
  15. Raised neurofilament levels in your spinal fluid – this test may not be part of routine care at your neurology centre. Neurofilaments are proteins that are released from damaged nerve fibres, and high neurofilament levels indicate greater damage and poorer outcome than low levels.
  16. Low vitamin D levels – this is controversial, but several studies have shown that people with MS with low vitamin D levels do worse than those with higher levels. These observations do not necessarily imply that by taking vitamin D you will do better. Low vitamin D levels may be related to reverse causation, in that the MS-associated inflammation uses up vitamin D; more inflammation indicates worse MS and is therefore linked with greater depletion of vitamin D levels.
  17. Smoking – smokers with MS do worse than non-smokers. This is modifiable and it is one of many reasons why you should try and give up smoking. 
  18. Comorbidities – people with MS who are obese, have diabetes, prediabetes, hypertension or raised cholesterol do worse than people with MS without these comorbidities.4
  19. Cognitive impairment – people with MS with poor cognitive function do worse than people with MS with good cognition. You can’t really assess your own cognition at present; you need to have it tested by a neuropsychologist.

‘It won’t happen to me’

Humans have interesting psychology in that they tend to consider themselves to be the exception to the rule. Gamblers don’t enter a casino to lose; they always believe they will win. A person with lung cancer who starts chemotherapy believes they will be one of the 10% who is cured. When someone is diagnosed with MS, they believe they will be one of the 30% with benign disease. (The current view among MS neurologists is that 30% of untreated people with MS will have benign disease.) 

This definition of ‘benign MS’ is based on having no or little disability at 15 years since onset, i.e., an EDSS score of 3.0 or less (no visible disability). However, when you interrogate people with so-called benign MS you find that more than 50% of them have hidden symptoms of depression, anxiety or cognitive impairment. Can we really justify this definition of benign MS? What is more, when you follow people with benign MS past 15 years, only 15% remain benign at 25 years and 5% at 30 years. If you get to 40 years of follow-up, half of these with benign MS will become disabled over the next 10 years.

Moving towards a more favourable outcome

Many will state that these figures are now out of date and there are newer and better figures, which show MS is a more benign disease. You are right, and there are several very good reasons for this. In population-based studies, the proportion of subjects with benign MS is greater than in hospital- or clinic-based studies; for example, in the Olmsted Mayo Clinic MS population, about 45% have benign disease at 15 years. The reason for this is that people with MS with benign disease often drop out of hospital follow-up, but still show up in population-based studies. 

The earlier diagnosis of MS, that is, identification of those who would not have been diagnosed in the past, is changing the definition of MS. For example, most people with a clinically isolated syndrome (CIS) are now being diagnosed as having MS. The wide use of DMTs is beginning to change the natural history of MS for the better; making sure that people with MS adopt a healthy lifestyle is another strategy that can be done in parallel. 

With currently available high-efficacy DMTs and the prospect of effective combination treatments in the future, the proportion of people with MS who experience normal ageing is set to increase. The blue areas illustrate the likely number of people with MS in each prognostic category.
With currently available high-efficacy DMTs and the prospect of effective combination treatments in the future, the proportion of people with MS who experience normal ageing is set to increase. The blue areas illustrate the likely number of people with MS in each prognostic category.
With currently available high-efficacy DMTs and the prospect of effective combination treatments in the future, the proportion of people with MS who experience normal ageing is set to increase. The blue areas illustrate the likely number of people with MS in each prognostic category.
With currently available high-efficacy DMTs and the prospect of effective combination treatments in the future, the proportion of people with MS who experience normal ageing is set to increase. The blue areas illustrate the likely number of people with MS in each prognostic category.

With currently available high-efficacy DMTs and the prospect of effective combination treatments in the future, the proportion of people with MS who experience normal ageing is set to increase. The blue areas illustrate the likely proportion of people with MS in each prognostic category.

The above figures illustrate what we aim to do with currently available high-efficacy DMTs (compared with older, lower efficacy treatments). We are simply trying to move you to the right, into a more favourable prognostic group. In other words, we want to make sure your MS is benign and that you reach old age with as healthy a brain as possible. Your brain reserve and cognitive reserve protect you from developing age-related cognitive impairment and dementia. MS reduces both of these reserves, which is why it is so important to protect them. With the prospect of effective combination treatments in the future, the proportion of people with MS who experience normal ageing is set to increase.

References

  1. Giovannoni G, et al. Brain health: time matters in multiple sclerosis. 2015, Oxford Health Policy Forum CIC.
  2. Miller DH, et al. Clinically isolated syndromes. Lancet Neurol 2012: 11:157–69.
  3. Weld-Blundell IV, et al. Lifestyle and complementary therapies in multiple sclerosis guidelines: Systematic review. Acta Neurol Scand 2022;145:379–92.
  4. Kappus N, et al. Cardiovascular risk factors are associated with increased lesion burden and brain atrophy in multiple sclerosis. J Neurol Neurosurg Psychiatry 2016;87:181–7.