Smoking in Multiple Sclerosis, NMOSD and MOGAD: Risk, Progression and Recovery After Attacks

Smoking and the risk of developing multiple sclerosis

The association between smoking and MS risk is one of the most consistent epidemiological findings in neuroimmunology. Meta-analyses indicate that people who smoke have, on average, approximately a 1.5-fold higher probability of developing MS than never-smokers. Many studies also show a dose-response relationship: the greater the cumulative smoking exposure, the higher the risk.

In the Smoking Attributable Risk in Multiple Sclerosis study, which included 9,419 people with MS and the same number of population controls, the estimated proportion of MS cases attributable to smoking was 13.1%. This is a population measure, not an individual prediction: it does not mean that any particular person's risk of MS is 13%. It reflects how substantial the contribution of smoking may be at the population level.

The 2026 umbrella review confirmed the overall picture: active cigarette smoking and waterpipe smoking were consistently associated with a higher risk of MS. The authors also emphasized that most available evidence remains observational, studies are heterogeneous, and a causal effect cannot be measured with the same precision as in a randomized clinical trial.

Why might smoking contribute to the development of MS?

The most likely explanation is a combination of mechanisms rather than a single pathway. Tobacco smoke causes chronic inflammation of the airways, changes the function of innate and adaptive immune cells, increases oxidative stress and may interact with genetic susceptibility to MS. Studies have described interactions between smoking and HLA risk alleles, supporting a “genetics + environment” model rather than a single-cause explanation.

One hypothesis of particular interest is lung irritation: combustion products and airway inflammation may be more important for MS risk than nicotine itself. This distinction has practical implications when choosing smoking-cessation methods.

What matters more in MS: nicotine or tobacco smoke?

This question is important because some patients are afraid of nicotine-replacement therapy — patches, gum or sprays — and continue smoking as a result.

A large Swedish cohort published in 2023 and including 9,089 people with MS compared active smoking, passive smoking and smokeless oral tobacco. Active and passive smoke exposure were associated with faster EDSS progression. Use of snuff did not show the same adverse association with progression.

This does not mean that nicotine is harmless, and it is certainly not a recommendation to use snuff. Smokeless tobacco has its own risks. The data do, however, support a practical conclusion: nicotine-replacement therapy should not be equated with continued smoking. For a patient who cannot stop cigarettes without pharmacological support, a nicotine patch or another approved nicotine-replacement method is usually far preferable to inhaling tobacco smoke.

Smoking and the effectiveness of multiple sclerosis treatment

It cannot be stated that smoking reduces the effectiveness of every disease-modifying therapy to the same extent. However, observational signals exist for some treatments.

For example, in a 2023 study of people with relapsing MS treated with dimethyl fumarate or fingolimod, current smoking was associated with a higher risk of relapse and overall disease activity. After multivariable adjustment, relapse risk remained higher in current smokers. Former smokers had activity measures closer to those of never-smokers.

The study was relatively small and does not prove a universal pharmacological interaction between cigarettes and all MS therapies. It does, however, support an important practical principle: effective MS treatment does not remove the need to stop smoking.

Vaping, e-cigarettes and heated tobacco: are they safer for people with MS?

At present there are no high-quality clinical data allowing e-cigarettes or heated-tobacco systems to be considered safe for people with MS, NMOSD or MOGAD.

The 2026 umbrella review specifically assessed this question and reached an important conclusion: among the included reviews, there were no studies directly evaluating the effect of e-cigarettes or vaping on MS risk or progression. The statement “vaping is safer for MS” therefore does not have an adequate evidence base.

Experimental studies show that e-cigarette aerosols can produce endothelial dysfunction, inflammation and disruption of the blood-brain barrier. These are mainly preclinical data and cannot be directly converted into numerical risks for humans.

Practical conclusion: switching from cigarettes to vaping should not be considered a proven neurologically safe long-term strategy. If an e-cigarette is used as a temporary step toward complete smoking cessation, it is preferable to time-limit that plan and define the final goal in advance — no smoking.

How to quit smoking with MS, NMOSD or MOGAD

The overall approach is the same as in people without a demyelinating disease: the best outcomes usually come from combining pharmacological and behavioral support.

• Nicotine-replacement therapy: patches, gum, lozenges and sprays. For a person with MS, these are generally preferable to continued smoking.
• Varenicline: one of the most effective medications for smoking cessation; prescribed with attention to contraindications and comorbidities.
• Bupropion: can be used in selected patients, but contraindications, drug interactions and seizure risk need to be considered.
• Behavioral support: individual or group programs, work on triggers, setting a quit date and support after smoking relapse.
• Treatment of sleep problems, anxiety and depression: these conditions often interfere with cessation and may require parallel treatment.

In MS, fatigue, cognitive symptoms and reduced physical activity should also be taken into account because they can make standard cessation programs more difficult. The plan should be realistic and should not rely only on “willpower”.

Key points