For the first study, Dr. Jorge Correale, of the Raúl Carrera Institute for Neurological Research in Buenos Aires, Argentina, and colleagues analyzed the body mass index (BMI) of 420 individuals aged 15 or 20 years.
At baseline, 210 of the 420 participants had MS and the other 210 did not have the disease.
Researchers found that participants who were obese at the age of 20 were twice as likely to develop MS later in life, compared to the individuals who were not obese.
In addition, researchers also found that those who had a higher BMI had higher levels of leptin in their blood.
This protein is produced by fatty tissues that regulate the storage of fat in the body, as well as appetite and immune response.
Because leptin promotes inflammatory responses in the body, Dr. Correale
says, this could explain the association between obesity and MS.