Smoking is an established risk factor for multiple sclerosis (MS). Smoking also worsens the course of disease for people who already have MS.
MS is an inflammatory disease that involves the breakdown of the protective layer around nerve cells in your brain and spinal cord. This protective layer is called myelin.
The exact cause of MS isn’t known, but it’s likely that certain environmental factors trigger its development in people who are genetically prone to MS. Smoking has been shown to be one of these environmental factors that can worsen the course of MS or increase your risk of developing it.
Harmful chemicals in tobacco smoke enter your bloodstream and then travel to tissues throughout your body. Smoking is also an established risk factor for many other chronic conditions, like lung cancer and cardiovascular disease.
Keep reading to learn more about the link between smoking and MS.
Smoking has been shown to worsen the course of MS and make you more prone to developing it.
Increased risk of MS
A combination of genetics and environmental factors are thought to play a role in the development of MS. Studies consistently report higher rates of MS in people who smoke.
In a 2022 study, researchers examined the smoking habits of 9,419 people with MS and an equal number of people without MS.
At the time of MS onset, 44.1% of people with MS and 35.9% of the control group had ever regularly smoked. Likewise, 38.1% of people with MS and 29.2% of people without MS reported still smoking.
Researchers reported the overall attributed factor of smoking for MS as 13.1%. The attributable factor is the statistic that researchers use to estimate the portion of a disease caused by a specific risk factor.
That means the researchers determined that at least 13% of cases of MS could be prevented through the avoidance of tobacco smoking.
Worse progression of MS
In a 2022 study from the United Kingdom, researchers examined how smoking and quitting smoking affected the progression of MS symptoms in 7,498 people.
Current smokers reported higher disability than those who had never smoked. Study participants with MS who continued to smoke had faster disease progression in all measured categories. These included surveys measuring the degree of depression and anxiety as well as motor disability and difficulty with walking.
Smoking and late onset MS
Late onset MS is usually defined as MS diagnosed over age 50 years.
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Smokeless tobacco
In a 2023 study, researchers aimed to examine the influence of smoking habits, exposure to snuff, and passive smoking on MS progression.
Snuff is a form of smokeless tobacco placed behind the upper lip. Passive smoking was a measure of tobacco smoke exposure at work or home.
The research team’s key findings were:
- High degrees of smoking were linked to a worse MS outlook.
- Passive smoking was associated with faster disease progression than never smoking.
- The use of moist snuff was associated with about the same disease progression as not smoking and slower disease progression than smoking or passive smoking.
Based on these results, researchers concluded that nicotine replacement therapy with smokeless nicotine sources, such as snuff, could be an attractive way for people with MS to quit smoking. However, researchers also acknowledged that smokeless nicotine therapy could have other harmful health effects.
The development of MS is complex. It likely involves a combination of environmental and genetic factors.
According to the MS Society, it’s very unlikely that smoking is 100% responsible for the development of MS. While smoking is not the only cause of MS, it can contribute to the risk.
The increased risk of MS is lower if you quit smoking than if you continue smoking your entire life.
In a 2023 study, researchers examined the effect of smoking on 103 people starting to take oral disease-modifying drugs to treat MS.
Researchers found that smokers started to experience MS symptoms sooner than nonsmokers, even after starting these drugs. The disease course in former smokers was similar to never-smokers.
In the 2022 study from the United Kingdom mentioned earlier, researchers found evidence that the disease progression slowed in people with MS who quit smoking, eventually matching disease progression in those who have never smoked.
Quitting smoking can be very difficult, but it’s possible. Stopping smoking can benefit many aspects of your overall health. Many people find it helpful to get outside support, like starting counseling or joining support groups.
Other methods to help you quit smoking include:
- nicotine replacement therapy, which comes in forms like:
- patches
- gums
- inhalers
- smoking cessation medications, such as Chantix and Zyban, that help reduce cravings and withdrawal symptoms
- alternative supportive therapies, like:
- hypnosis
- meditation
According to the MS Society, some studies show that vapor from e-cigarettes without nicotine may damage cells that protect your brain, but more research is needed.
It’s less clear how nicotine products affect the risk of MS development. There’s not a lot of research or evidence about the effects of nicotine gum on MS.
While smoking and vaping are thought to be harmful in MS, nicotine is also harmful. So, nicotine gum can be a method to stop smoking, but it’s healthier to eventually stop using the gum, too.
In a 2024 review of studies, researchers found that most studies showed a relationship between environmental smoke exposure and the risk of MS, especially childhood exposure.
Smoking is a well-established risk factor for the development of MS and worsening course of disease. People who quit smoking have been shown to have a better outlook and may even eventually match the outlook of people who have never smoked.
Research has shown that at least 13% of cases of MS could be prevented through the avoidance of tobacco smoking.
Smoking has many side effects on your health. It’s an established risk factor for lung cancer and cardiovascular disease.
If you have MS or a family history of MS, it’s especially crucial to quit smoking, as it can increase your risk of developing the disease or worsen your symptoms or disease progression.