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Certain diabetes medications may affect one’s risk of developing multiple sclerosis. Christina House/Los Angeles Times via Getty Images
  • Multiple Sclerosis (MS) is a potentially debilitating condition, most cases of which are unexplained.
  • A recent piece of research has proposed that people under the age of 45 with type 2 diabetes who are being treated with anti-hyperglycemic medications may be less likely to develop MS.
  • The same study found that those who start treatment with anti-hyperglycemic medication over the age of 45 may be more at risk of developing MS.

Multiple sclerosis (MS) is a potentially debilitating condition that affects the ability of nerves to signal properly, and it is twice as common in women as it is in men. Its potential causes are yet unclear.

MS is considered an autoimmune disease, and like other autoimmune conditions, its causes are thought to be a combination of environmental and genetic factors.

MS occurs when the fatty protective sheath around nerve cells known as myelin degenerates, this affects cell signaling and causes symptoms such as vision problems, difficulty standing as well as bladder control and sexual problems. It can even cause partial paralysis.

Some people have both type 2 diabetes (T2D) and MS. Researchers have observed that people with T2D who receive anti-hyperglycemic drugs experience some improvements in their symptoms. Earlier this year, researchers launched a clinical trial to repurpose metformin, an anti-hyperglycemic drug, as an MS drug.

A recent piece of research has looked into the effects of anti-hyperglycemic drugs used to treat T2D on MS risk.

The retrospective study published in the journal Heliyon has shown that using anti-hyperglycemic drugs can help to reduce people’s risk of developing MS if the onset of T2D and treatment is before the age of age 45.

However, the researchers also found that these drugs can increase the risk of developing in those over the age of 45, particularly in women.

In the current study, researchers from the University of Arizona, Tucson, examined a cohort of over 5 million people with T2D from the Mariner insurance claims database, and over 1.5 million people were included in their final analysis.

The researchers then matched participants who had either been exposed to anti-hyperglycemic medications, including insulin, metformin, sulphonylureas, glitazones, and DPP4 inhibitors to treat their T2D, and those who had not.

Their findings showed that T2D patients who took anti-hyperglycemic medications had a 22% decreased risk of developing MS over an average follow-up of 6.2 years in patients who were younger than 45 years when they started taking them.

When individual drugs were analyzed, sulfonylureas alone or in combination with metformin were most significantly associated with a decrease in the risk of developing MS in the time frame studied.

Conversely, they also found that people who had started treatment over the age of 45 had a 16% increased risk of developing MS.

Those who had the highest number of comorbidities saw a 36% increase in the risk of developing MS if they took anti-hyperglycemic drugs.

When researchers looked at males and females separately, they found that females were more at risk following anti-hyperglycemic use than males, for whom confidence in an association was low.

Researchers have proposed the difference could be due to menopause, which occurs in most women in their late 40s and early 50s, though perimenopause can start earlier.

They explain that T2D control often worsens in women after menopause due to the loss of estrogenic control of insulin. This can lead to significant inflammation, they say, which could similarly lead to a worsening of MS symptoms.

However, they also note that the rate of MS overall is lower after the age of 40, and therefore menopause, as has previously been found.

Having one autoimmune disease, where problems are caused by the immune system attacking cells it shouldn’t, is associated with an increased risk of other forms of autoimmune disease.

People with T2D, for example, although it is not considered an autoimmune disease, are more at risk of developing multiple sclerosis, with women under the age of 50 with T2D being most at risk, a study of a cohort in Taiwan showed. The authors suggested the reasons were unclear, noting that while both are understood to have some genetic factors, there are no genetic risk factors in common between the condition.

Dr. Hana Patel, GP specialist in chronic disease and mental health and Mindset Coach told Medical News Today in an interview:

“It’s another risk factor that’s associated with MS. Though, it’s not the diabetes [that] causes it, but because you’re more likely to get other autoimmune conditions, it’s more likely to happen to someone who’s got diabetes.”

The findings are complicated by the fact that MS diagnosis can often be made years after the onset of symptoms, according to Dr. Achillefs Ntranos, chief neurologist and MS specialist at Treat MS.

“The findings of the paper are intriguing, but I would not say they are controversial, as there could be a biological basis for them. Glucose metabolism is essential for the immune response, so modulating that could have an effect in immune-mediated diseases, such as MS,” he told MNT.

“However, this study has some limitations as it is a retrospective study based on an insurance claims database, which can harbor certain biases that can affect the results. Therefore, the findings of this study need to be replicated in another cohort to strengthen their scientific validity,” he added.