- MS Australia-supported research showed that in people with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), those who smoke had a relapse rate 2.2 times that of people who had never smoked.
- People with MOGAD who were former smokers had similar relapse rates to people who never smoked.
- This suggests that quitting smoking can significantly reduce disease activity for people living with MOGAD.
What is MOGAD?
Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an inflammatory disorder of the central nervous system (brain, spinal cord and optic nerves). Similar to MS, in MOGAD there is loss of the myelin coating around the nerves, disrupting the transfer of messages within the central nervous system. It is a separate distinct disorder to MS, with a different underlying disease process. In MOGAD, the immune system mistakenly makes antibodies that target the myelin oligodendrocyte glycoprotein (MOG) molecule. This causes the loss of myelin (demyelination).
MOGAD can have similar symptoms to MS, but there are differences. For example, in MS, optic neuritis (inflammation of the nerve connecting the brain and eye) often affects one eye but rarely both. In MOGAD, optic neuritis commonly affects both eyes. There are also differences in how lesions in the brain look on scans.
Clinical attacks in MOGAD (also termed flares, exacerbations, or, if a recurrence, relapses) are driven by sudden inflammation in the central nervous system.
Smoking and its impact on disease progression
In MS, tobacco smoking can significantly increase disease progression, by around 55% .
MOGAD is a relatively newly-recognised disease, so there is limited information available at this early stage. In people with MOGAD, current smoking is linked with poorer recovery. But it is not clear whether smoking affects the risk of relapse. It is also not known whether other health factors that affect blood vessels – known as vascular risk factors – affect relapse risk. These factors include high blood pressure, high blood cholesterol, type 2 diabetes and increased body size.
What did the researchers do?
The team, including MS Australia-supported researchers, analysed data from 172 people with MOGAD from the Demyelinating Research Tissue Bank in the UK. They investigated the link between relapse rates and smoking status and vascular risk factors.
In this study, smoking status was categorised as never smoked, past smoker or current smoker. Vascular risk factors were previously diagnosed high blood pressure, high blood cholesterol or type 2 diabetes. Vascular risk factors also included increased body size as measured by body mass index (BMI). BMI is calculated by body weight in kilograms divided by height in metres squared. In this study, increased body size was defined as BMI greater than 25 kg/m2.
Relapses were defined as a new clinical attack from MOGAD more than 30 days after an earlier attack. The researchers analysed the time it took to have a relapse and the annual relapse rate.
Researchers also took into account a person’s background factors. These included age at onset of MOGAD, sex, the type of first clinical attack (e.g., optic neuritis or acute disseminated encephalomyelitis (inflammation of the brain and spinal cord)), use of steroid medications after the first attack and use of immune-suppressive treatment.
What did the researchers find?
Published in Multiple Sclerosis Journal, the researchers showed that people with MOGAD who were current smokers had a relapse rate more than double (2.2 times) that of people who had never smoked.
The relapse rate was similar between people who were past smokers and people who had never smoked. There were no differences in the time to relapse between current smokers and never-smokers.
Vascular risk factors did not affect relapse rates or time to relapse after taking background factors into consideration. However, the researchers noted that studies with a bigger group of people with MOGAD are needed to confirm this.
What does this mean for people with MOGAD?
This study suggests that smoking can worsen aspects of the disease in people with MOGAD. People who had quit smoking had similar relapse rates to those who have never smoked, suggesting that quitting may reduce this risk.
Similarly in MS, quitting smoking is beneficial. Every 10 years a person with MS stays smoke-free lowers their risk of disability progression by about 30%.
For information about quitting smoking, see MS Australia’s Living Well with MS resource, MS Australia’s Health and Wellbeing page on smoking,  Quitline, or the Australian Government.
