Being obese at the time of multiple sclerosis (MS) diagnosis has been linked to higher levels of current and subsequent disability, according to research from the German National MS cohort.
The researchers have suggested that reverting to a healthy weight may improve clinical outcomes for patients after MS diangosis. However, it has not been clear whether obesity is linked to faster disability progression after the disease has been diagnosed.
To answer this question, the researchers analysed data from 1066 participants with relapsing-remitting MS from across Germany who were taking part in The German National MS study. Over a quarter (29.5%, 315) of participants were men with an average age of 33.
At the time of MS diagnosis, 159 patients (15%) were obese with a BMI of at least 30. Co-existing conditions associated with obesity such as type 2 diabetes and high blood pressure were found in 68 patients (6.5%).
Measuring disability in obese patients
Levels of disability in the participants were measured every two years for a total of six years after the MS diagnosis, using the Expanded Disability Status Scale (EDSS). The scale ranges from 0 to 10 in increments of 0.5. Obesity at the time of MS diagnosis was not associated with a higher relapse rate, or a higher build-up of nerve damage, as seen on MRI brain scans, over the six years.
However, levels of disability were higher at the time of MS diagnosis and at each of the subsequent three-time points, after considering participants’ age, sex, and smoking status.
Obese participants developed greater levels of disability over a shorter period than non-obese participants. Obese patients reached level three of EDSS after just under 12 months, on average, compared with nearly 18 months for those who were not obese. Obese patients were also twice as likely to reach level three within six years, regardless of what type of drug treatment they were on.
Obese patients will decline faster after MS diagnosis
The risk of reaching EDSS level three within six years in this group was twice as high in obese patients as it was in those who were not. This fell to an 84% heightened risk after factoring in sex, age, and smoking status.
Notably, being overweight (having a BMI between 25–29.9) at the time of MS diagnosis was not clearly associated with higher rates of disability then or subsequently.
As this, study was purely observational the precise cause of the issue could not be identified. The researchers acknowledge that BMI was only assessed at the beginning of the study and co-existing conditions were limited to type 2 diabetes and high blood pressure.
“Our finding that obesity, but not overweight in MS patients, is associated with a poorer outcome suggests a threshold effect of body mass on disability accumulation in MS,” explained the authors.
“These data suggest that dedicated management of obesity should be explored for its potential merit in improving long-term clinical outcomes of patients diagnosed with MS,” they concluded.
A full report of the findings has been published in the Journal of Neurology Neurosurgery & Psychiatry.