Obesity and Pediatric Multiple Sclerosis

This study examines whether being overweight or obese affects how multiple sclerosis (MS) progresses in children and young adults. Researchers will compare young people with MS to healthy children matched by age, sex, and weight to understand the connection between body weight and MS disease activity. **You may be eligible if...** - You are between 10 and 20 years old - You have been diagnosed with relapsing-remitting MS within the past 3 years - OR you are a healthy child or young adult willing to serve as a comparison participant **You may NOT be eligible if...** - You have a progressive form of MS - You have another active immune system disease - You have had steroid treatment within 30 days of enrollment - You have a condition affecting the brain's white matter other than MS - You have MOG antibodies (suggesting a different diagnosis) Talk to your doctor to see if this trial is right for you.