Obesity is never healthy, and that may be especially true for people who also develop multiple sclerosis.

Obese people with MS are likely to see the disability linked to the disease rapidly worsen, said German researchers who followed more than 1,000 patients in a new study.

Weight loss, they suggested, might help slow the progression of the disease.

“The findings from this study raise important questions about the role of elevated BMI (body mass index) on mechanisms that drive neurologic disability in MS,” said Dr. Fiona Costello, a professor of neurology at the Cumming School of Medicine at the University of Calgary in Canada.

Obesity correlates with a higher risk of developing MS, she said. “What has not been clear is how obesity is linked to disease severity and disability progression in individuals with MS. But a large body of published literature has shown that deleterious disease associations with obesity are not unique to MS.”

Obesity already has been linked to an increased risk of heart disease and type 2 diabetes, as well as cognitive impairment and dementia, said Costello, who had no part in the study.

This study can’t prove that obesity speeds up greater disability in patients with MS, only that the two seem to be connected, the researchers noted.

Still, “obtaining a normal weight is likely beneficial for people with MS,” said Dr. Asaff Harel, director of the multiple sclerosis center at Lenox Hill Hospital in New York City. He played no role in the research.

MS is an autoimmune disease that affects the central nervous system. It can cause permanent disability or even death, and there is no cure. Symptoms usually start in the 30s or 40s.

The study team was led by Dr. Jan Lunemann, a professor of neurology at the University of Munster. The researchers collected data on 1,066 patients with relapsing-remitting MS who took part in a German nationwide MS study.

When their MS was diagnosed, 15% of the patients were obese, meaning they had a BMI of 30 or higher. Almost 7% also suffered from type 2 diabetes or high blood pressure — conditions linked to obesity. The researchers checked participants’ disability levels every two years over six years.

Although obese patients didn’t have a greater relapse rate or more nerve damage over the course of the study, they had greater disability at the time of diagnosis. And their levels of disability grew faster than those of people who weren’t obese, the researchers found.

Obese patients reached a higher level on the Expanded Disability Status Scale in just under 12 months, compared with nearly 18 months for those who weren’t obese. Patients with obesity were also more than twice as likely to reach this higher level of disability within six years, regardless of which drugs they were treated with, the researchers found.

Patients who were overweight but not obese did not face a higher risk of disability. “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,” the researchers wrote.

“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 added.

Weight management should be explored as a potentially modifiable risk factor for disability progression in MS patients, Costello said.

“It stands to reason for any individual with or without MS, working to achieve the best possible BMI will benefit their overall health, particularly since motor disability and cognitive decline, which independently co-associate with obesity, are challenges and concerns for people living with MS,” she said.

Conversations between health care providers and MS patients about body weight need to be approached with an honest acknowledgment about what we know and don’t know about the many implications of obesity, Costello said.

Also, “patient-centered discussions need to be handled with sensitivity, being mindful that body image perceptions are an important part of health and wellness,” she added.

Harel said several studies have shown that obesity is a risk factor for the development of MS, and some have suggested that obesity is associated with worse MS outcomes.

“We do not precisely understand the pathophysiology of this,” he said. “The treatment of MS is not solely about disease-modifying agents. One should take a holistic view, as regular exercise, healthy diet and adequate sleep likely impact MS severity.”

The report was published online Nov. 1 in the Journal of Neurology, Neurosurgery & Psychiatry.

More information

For more on multiple sclerosis, see the U.S. National Institute of Neurological Disorders and Stroke.

SOURCES: Fiona Costello, MD, professor, neurology, Cumming School of Medicine, University of Calgary, Alberta, Canada; Asaff Harel, MD, director, multiple sclerosis center, Lenox Hill Hospital, New York City; Journal of Neurology, Neurosurgery & Psychiatry, Nov. 1, 2022, online