The Effects of Body Mass Index (BMI) on Multiple Sclerosis (MS) Progression

Background: Multiple Sclerosis (MS) is a progressive neurological disease leading to loss of function and disability. MS and obesity are both considered inflammatory diseases, and they might be linked through pathophysiological processes. The relationship between Body Mass Index (BMI) and MS progression is unknown.

Objectives: To evaluate the relationship between BMI and MS progression as measured by the Expanded Disability Status Scale (EDSS), MRI new lesions, relapse rate, and the Timed 25 Foot Walk (T25FW).

Methods: Subjects were identified through age, gender, race, disease duration, smoking, and MS type from an MS center in New York City and followed retrospectively for 5 years. Logistic regression analysis was performed to determine the association between the baseline BMI and MS progression: disability, new MRI lesions, relapse rate, and the average 25-foot walk (n=150).

Results: The mean age was 45.5 years (SD 14.3), 79 % were females and 59% were Non-Hispanic Whites, 68% were never smokers, and 77% had relapsing-remitting MS (RRMS). The mean BMI was 27 with 40 (27%) being classified as overweight and 46 (30%) as obese. 63 (42%) developed disability, 70 (47%) had increased brain MRI lesions and 42 (28%) had increased spine MRI lesions, 110 (73%) had increased relapses by at least one relapse during the 5 years, and 38 (25%) had 20% increase on the 25FW. The odds of having increased EDSS by at least 1 point in obese patients with mild disability was 8 times greater than those with normal BMI (p=.017) controlling for age, gender, race/ethnicity, smoking history, disease duration, brain changes, number of relapses and MS type. The odds of having new brain MRI lesions was 6.2 times greater in overweight subjects (p<.0001) and 2.6 times greater in obese subjects (p=.048) than in subjects with normal BMI controlling for age, gender, EDSS, number of relapses and disease duration. The odds of having at least 1 relapse in 5 years was 3.8 times (p=.040) in obese subjects than non-obese controlling for gender and smoking history. The odds of having 20% change on the 25-foot walk was 1.1 (p=.047) times for each increase of one unit of the baseline BMI controlling for age, gender and disease duration. Non-Hispanic Blacks had 5 times greater odds to have high disability (p=.015) than non-Hispanic Whites controlling for age and duration of disease, and current smokers had 5 times greater odds to have increased disability than never smokers (p=.03).

Conclusions: BMI may have an important role in MS outcomes. Assessment and addressing a plan of care with dietary guidelines and weight control programs for patients with MS may aid in minimizing the progression of the disease and other chronic illnesses such as, cardiovascular diseases and diabetes.