- Study results showed that the incidence of relapses was higher in smokers than in non-smokers.
- Smokers were 2.72 times more likely to experience a relapse and were also more than twice as likely to experience any form of disease activity.
- Former smokers had a disease course that was similar to that of people who had never smoked before.
A new study published in the journal of Multiple Sclerosis and Related Disorders found that people with relapsing-remitting multiple sclerosis (RRMS) who receive oral disease-modifying therapies (DMTs) are more likely to experience a relapse or any form of disease activity if they are smokers.
The researchers also discovered that former smokers had a disease course similar to those who had never smoked before, indicating that it is not too late to give up!
What was the aim of the research?
It is well known that smoking can increase the risk of developing MS and can be a risk factor for poorer disease outcomes. However, there are few data on how smoking can impact the effectiveness of oral medications.
A team of researchers in Japan recently examined the medical records of 103 people living with RRMS and receiving DMTs (either fingolimod or dimethyl fumarate) between 2012 and 2019 in one centre.
What did the researchers do?
At the start of treatment, 19 (18.4%) patients were current smokers, with 15 (78.9%) of them continuing to smoke until the end of the study. Of the 84 non-smokers, 23 (27.4%) were previous smokers, and 61 (72.6%) had never smoked.
During the follow-up period, a total of 27 patients (26.2%) experienced a relapse, and 49 (47.6%) had any form of disease activity — either a relapse or the appearance of new lesions on MRI scans.
What did the study find?
Results showed that the incidence of relapses was higher in smokers than in non-smokers (47.4% vs. 21.4%), as was the percentage of patients who experienced any form of disease activity (79% vs. 40.5%).
The time from the start of treatment to experiencing relapse was also significantly shorter in smokers than non-smokers, with smokers being 2.72 times more likely to experience a relapse over the observation period. Smokers were also more than twice as likely to experience any form of disease activity.
After accounting for various parameters — such as age, biological sex, and disease activity at the start of treatment — smoking stood out as an independent risk factor for relapse and disease activity in people receiving oral DMTs, fingolimod and/or dimethyl fumarate.
What does this mean for people with MS?
The researchers concluded that “RRMS patients should be advised to stop smoking even after initiation of [DMTs]” adding, “Education about smoking cessation is necessary for patients with RRMS under [disease-modifying medications] who smoke.”
These remarkable findings send a clear message regarding smoking in people with MS. They add to the wider body of unequivocal evidence that smoking worsens MS.
Experts strongly recommend that anyone with MS, at any stage, stops smoking as soon as possible.
People with MS who smoke experience a lower quality of life, as well as an increased risk of depression and anxiety.
Smoking increases the risk of MS progression by around 55%, making it a key risk factor for disease progression. You can read more about this in our Modifiable Lifestyle Guide for people with MS.
The good news is that quitting smoking at any time is beneficial for people with MS.
There are excellent general resources available at Quit, to help people quit smoking. The video in this article, by MS Australia-funded researcher Dr Claudia Marck, talks about some of the additional challenges of quitting for people with MS.
For more information and support, please talk to your healthcare team.
