#ECTRIMS2021 – Quitting Smoking May Help Slow MS Progression
Editor’s note: The Multiple Sclerosis News Today team is providing in-depth coverage of the virtual 37th Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS), Oct. 13–15. Go here to see the latest stories from the conference.
Multiple sclerosis (MS) patients who quit smoking show a slower rate of disease progression than those who continue to smoke, according to a large real-world study in the U.K.
Moreover, disease progression in former smokers was found to be comparable to that of people who had never smoked, highlighting the beneficial effect of smoking cessation in this patient population, according to researchers.
“When smokers quit, there is a slowing in the rate of motor disability deterioration so that it matches the rate of motor decline in those who have never smoked,” the researchers wrote.
The takeaway: “Smoking cessation is beneficial for people with MS.”
These findings were shared by Jeff Rodgers, PhD, of the Swansea University Medical School, in the U.K, at the 37th Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS), running virtually Oct. 13-15.
The oral presentation was titled “The impact of smoking cessation on multiple sclerosis disease progression.” The findings were simultaneously published in the journal Brain.
A large body of evidence supports smoking as an influencing factor of MS development and progression. However, whether smoking cessation has a beneficial effect on disease progression over time remains unclear.
To address this knowledge gap, Rodgers and other researchers with the UK MS Register analyzed data from adults with MS participating in the register study — established in 2010 by the Swansea University Medical School, in Wales, and funded by the MS Society UK.
Demographic, lifestyle, and patient-reported outcome (PRO) data were collected between 2011 and 2020 on a biannual basis.
The study’s main goals were to assess the effect of smoking status in three PROs, one of them the MS Physical Impact Scale (MSIS-29-Phys), which measures the impact of disease on motor skills. The other PROs were the MS Walking Scale (MSWS-12), a measure of MS impact on walking abilities, and the Hospital Anxiety and Depression Scale (HADS-Anxiety and HADS-Depression), a general assessment of anxiety and depression.
For all measures, higher scores indicate greater disability.
A total of 7,983 patients provided information on their smoking status and had completed at least one of the PROs. Nearly half (48.3%) had never smoked, while 35.3% were former smokers, and 16.5% were active smokers.
The results showed that, at the study’s start, current smokers “were younger and had higher median anxiety and depression scores,” while former and current smokers “had a higher level of disability” than never smokers, Rodgers said.
After adjusting for influencing factors — such as daily smoking level, age, sex, ethnicity, and disease duration and type — the researchers found that active smokers had 3–4% higher scores for all PROs relative to those who had never smoked, indicating higher disability and poorer mental health.
There were no major differences between former and never smokers in terms of walking abilities at the study’s start.
In addition, in both former and current smokers, the more cigarettes previously or currently smoked per day, the higher the PRO scores — except for anxiety in former smokers, which was stable across all smoking levels.
When analyzing the data of a subset of 923 MS patients who had annual records over five years, the team found that motor disability and depression significantly worsened over time, regardless of smoking status, while anxiety remained generally stable.
However, at the study’s start, motor and walking difficulties were greater in both former and current smokers, compared with patients who had never smoked.
Over time, former smokers had comparable anxiety and depression to never smokers and showed a slower motor disability progression than active smokers — approaching that of patients who had never smoked. Current smokers consistently showed significantly worse motor disability and mood, relative to the other two groups.
Next, the researchers evaluated whether smoking status influenced time to disease worsening or progression among 4,642 participants with at least three assessments spaced no more than nine months apart.
Disease progression was defined as a 10-point increase in the MSIS-29-Phys and MSWS-12 scores, or a two-point increase in the HADS-anxiety and HADS-Depression score — both of which are considered clinically relevant.
After adjusting for the same influencing factors, the results showed that current smokers “were between [25-30%] more likely to have a progression event than never smokers,” Rodgers said.
Also, there was no statistically significant difference in the rate of disease worsening between former and never smokers.
These findings suggest that “smoking causes real disability progression and mood worsening for people with MS, but when you stop smoking, that worsening stops as well,” Rodgers said.
“This is a very important and hopeful message to people with MS,” Rodgers concluded.
In the published study, the researchers noted that the number of former smokers among MS patients in the registry is higher than the national average.
“This suggests that [people with MS] may not be receiving sufficient encouragement and support to stop,” they wrote.
“This failure is in common with a number of other conditions in which smoking is known to have a negative impact,” they added, noting that “recognition of such a failure has led to calls for advice about smoking cessation to be included in standard clinical guidelines.”
The team said their findings “have provided further impetus for [people with MS] to stop smoking.”