A large study published in Acta Neurologica Belgica suggests that obesity may increase the risk of developing myasthenia gravis (MG), adding to growing evidence linking excess weight to immune-related diseases.
Researchers analyzed health data from nearly 4 million adults aged 20 and older using the Korean National Health Insurance Service database. They grouped the participants by body mass index (BMI), ranging from underweight to severe obesity and followed them for 10 years to see who developed MG.
Over the course of a decade, 799 of the participants were diagnosed with MG. The results showed that individuals with obesity had a significantly higher likelihood of developing MG compared with those in the normal BMI range. The risk increased steadily alongside BMI, with people in the highest obesity category facing up to 1.88 times the risk of developing the disease.
Researchers observed a similar pattern when looking at abdominal obesity, measured using waist circumference. Those with higher waist measurements were more likely to develop MG, and the risk rose progressively across increasing waist size categories.
Overall, individuals with obesity were estimated to have between a 20% to 88% higher risk of MG than those with normal weight. The findings were consistent across age and sex groups, suggesting that the relationship between obesity and MG risk is broadly applicable across the adult population.
Learn more about MG causes and risk factors
The authors suggest that chronic inflammation associated with obesity may help explain the link. Excess fat tissue produces inflammatory molecules and alters immune system activity, potentially triggering autoimmune responses. Changes in hormones, such as leptin and adiponectin, as well as increased production of immune cells and antibodies may also contribute to the development of MG.
The study also found a slightly higher risk of MG among men who were underweight, though this finding was less clear and needs more research.
The study’s authors say their findings highlight obesity as a potential modifiable risk factor for MG, though they emphasize that further studies are needed to confirm the relationship and understand the underlying mechanisms.
“The present study showed that obesity is associated with the subsequent risk of MG and the risk of MG was more increased in those with higher BMI,” they concluded. “Because the causal relationship between obesity and MG remains uncertain, further prospective and pathophysiologic studies are needed.”
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