Smoking and Multiple Sclerosis

How the habit may increase risk of the disease

Table of Contents
View All
Table of Contents

Smoking is thought to be a risk factor for developing multiple sclerosis (MS). The habit is also strongly associated with having a worse disease course and with decreased effectiveness of MS treatment. Even children exposed to secondhand smoke are more likely to develop MS later in life than their peers.

There are no established methods of preventing yourself from having MS; experts suggest that there may be environmental and genetic contributors. Nevertheless, the link between MS and smoking has been so consistent and convincing that leaders in the field, including the National Multiple Sclerosis Society, recommend smoking cessation for people who have been diagnosed with MS or who are at risk of developing MS, as well as their spouses and parents.

While researchers have been attempting to pinpoint the reason for the relationship between MS and smoking—and have come to some conclusions—many questions still remain.

How Cigarettes Increase the Risk of MS
Verywell / Cindy Chung

Smoking, Secondhand Smoke, and MS Risk

Several studies in recent years have identified a higher risk of becoming diagnosed with MS among smokers, which has been estimated to be double that of nonsmokers. Secondhand smoke is also strongly associated with MS.

This link appears to be related to several factors, including smoke-induced alterations of the immune system. Smoking and secondhand smoke change the immune system in more than one way. They may:

  • Interfere with your immunity, making you more prone to infections
  • Increase the risk of becoming sick after exposure to Epstein-Barr virus (EBV), a common virus that may contribute to MS
  • Predispose you to produce autoantibodies, which are immune cells that mistakenly attack your own body

So far, research suggests that smoking does not appear to be an independent risk factor for MS. This means that it probably causes changes in your body to induce MS if you are already at risk, rather than singlehandedly causing MS.

If you or your child is at risk of MS, then avoidance of smoking and secondhand smoke may help prevent the disease.

You or your child may be at risk of MS if:

  • You have a blood relative who has MS
  • Autoimmune disease, such as lupus or rheumatoid arthritis, runs in the family
  • You have had a demyelinating episode, which can be a one-time event—described as a clinically isolated syndrome (CIS)—or may be the first of future multiple sclerosis exacerbations
  • You have had an infection with EBV
  • You have the presence of the HLA-DR15 gene: This gene is not the only gene that can predispose someone to MS, and it does not have to be present for MS to develop.

Smoking and MS Progression

Smoking is also directly linked to MS progression. Smokers are more likely to have frequent relapses and to advance from relapsing-remitting MS (RRMS) to secondary progressive MS (SPMS), which is a more aggressive form of the disease.

Smokers with MS also tend to have more extensive damage in the brain than those with MS who are not exposed to smoking.

Because smoking can prompt you to make autoantibodies, the same autoimmune changes that predispose you to developing MS can also predispose you to relapses.

It is also well established that smoking reduces the function of the immune system throughout the whole body, making you more susceptible to infections. Infections can trigger a worsening of your MS symptoms. And smoking also interferes with healthy lung function, specifically predisposing you to lung infections.

It is still not entirely clear which substance in cigarettes worsens the MS disease process, and there may be several other additional factors at play that make MS worse for smokers.

How Smoking Can Impact MS Treatment

Not only does smoking increase your risk of developing MS and alter your disease course, but it also interferes with the effects of the medications used for the treatment of MS.

For example, smoking is associated with worsening disease when using Tysabri (natalizumab), a potent disease-modifying treatment for MS. Researchers have found that smokers produce antibodies that fight the medication, making it less effective.

Avonex, Rebif, and Plegridy—all brands of interferon beta-1a (IFNβ-1a)—are commonly used treatments for MS. Smokers with MS have an increased risk of making antibodies to IFNβ-1a, potentially making it less effective.

Smoking Cessation's Effect

You may not see the point in quitting smoking if your MS is already at a very advanced stage.

However, the number of cigarettes and length of time that a person smokes is linked to the severity of the disease. And quitting may slow the disease process and help preserve key cognitive functions (including memory, abstract reasoning, and verbal skills).

Quitting Help

Quitting cigarettes is never an easy thing, particularly if you believe that smoking helps you cope with the stress of living with MS. But you cannot ignore the fact that the benefits of quitting far outweigh any perceived benefit cigarettes may offer.

Committing to quit is step 1. But to set yourself up for success, it's important to then educate yourself as to what to expect, from symptoms of nicotine withdrawal to cravings and more.

Devise a quit program that speaks to issues like these as well as your personal motivations (e.g., some people see success in using a rewards system). You might also want to speak with your healthcare provider to see what quit smoking aids might be right for you.

If you don't know how to stop, help is available. Call 1-800-QUIT-NOW (1-800-784-8669) to connect directly with a staffed hotline in your state. The National Cancer Institute also offers an instant messaging LiveHelp hotline.

You may also find support groups, apps, and resources provided by helpful.

A Word From Verywell

MS is not considered a preventable disease. Yet the higher risk of MS that is associated with smoking suggests that the risk of developing MS can be modified. If you have risk factors for MS, one of the ways you can reduce your risk of getting the condition is by staying away from cigarette smoke. Remember, too, that if you already have been diagnosed with this disease, a complete look at your lifestyle is worthwhile, as stress, sleep, and other factors can influence how you feel.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Wingerchuk DM. Smoking: effects on multiple sclerosis susceptibility and disease progression. Ther Adv Neurol Disord. 2012;5(1):13-22. doi:10.1177/1756285611425694

  2. Petersen ER, Søndergaard HB, Laursen JH, et al. Smoking is associated with increased disease activity during natalizumab treatment in multiple sclerosis. Mult Scler. 2019;25(9):1298-1305. doi:10.1177/1352458518791753

  3. Hedström AK, Ryner M, Fink K, et al. Smoking and risk of treatment-induced neutralizing antibodies to interferon β-1a. Mult Scler. 2014;20(4):445-50. doi:10.1177/1352458513498635

By Julie Stachowiak, PhD
Julie Stachowiak, PhD, is the author of the Multiple Sclerosis Manifesto, the winner of the 2009 ForeWord Book of the Year Award, Health Category.