BY DAN HURLEY
INDIANAPOLIS— Overweight and obese patients were more likely than those of normal weight to show a significant progression of their disease markers or symptoms of multiple sclerosis (MS) during five years of follow-up, according to a new study presented here as a poster today at the annual meeting of the Consortium of MS Centers.
Based on a review of case records for 150 patients at a single center, the retrospective analysis was the first study to examine the effects of body mass index (BMI) on progression of multiple sclerosis in adults. The findings echo those of recent studies showing that higher weight in youth is associated with both a greater risk of developing MS and an earlier age of onset. But because this and other studies have been observational rather than randomized trials, the results provide no insight into causality, let alone mechanism, said neurologists who reviewed the abstract for the Neurology Today Conference Reporter.
The study author agreed that the study has its limitations and needs to be followed up with a randomized prospective trial, but said that in the meantime, it provides useful clinical information for neurologists and patients alike.
“It’s 150 patients from a single center, and it’s retrospective,” said study author Aliza Ben-Zacharia, DrNP, ANP, MSCN, a nurse practitioner and neurology teaching assistant at the Corinne Goldsmith Dickinson Center for MS at Mount Sinai Health System in New York. “But regardless of the limitations, it’s good, valid information. Patients always want to be proactive and to be able to change the course of their disease and have some control. We can point to the data and suggest that patients with MS may consider participating in weight management programs and may schedule an appointment with a nutritionist for proper counseling.
“We don’t know yet if you lose weight, your risk goes down,” she added. “All we know for now is there is a remarkable association between weight, MRI, and [scores on] the Extended Disability Status Scale [EDSS]. I think that this is sufficient data to share with patients. Some patients will want to take ownership of the disease and enroll in weight management programs and lose the weight.”
Dr. Zacharia conducted a logistic regression analysis to determine the association between baseline BMI of 150 patients at her center and their MS progression over five years retrospectively as measured by EDSS, new lesions on MRI, relapse rate, and the Timed 25-Foot Walk (T25FW).
The mean age was 45.5 years; 79 percent were female; 68 percent were never smokers, and 77 percent had relapsing-remitting MS. The mean BMI was 27, with 27 percent of patients classified as overweight and 30 percent as obese.
After controlling for age, gender, race/ethnicity, disease duration, brain changes, number of relapses, and MS type, the patients’ odds of having an increased EDSS by at least one point was eight times greater in obese patients with mild disability compared to those with normal BMI (p=0.017).
The odds of having new brain MRI lesions was 6.2 times greater in overweight subjects (p<0.0001) than in subjects with normal BMI after controlling for potential confounders. But in a violation of any expected dose-response rate between weight and MS, the odds were only 2.6 times greater in obese subjects (p=0.048).
The odds of having at least one relapse in five years was 3.8 times greater (p=0.47) in obese patients than in their non-obese counterparts after controlling for gender and smoking history. The odds of having a 20 percent change on the T25FW were 1.1 times (p=0.040) greater for each increase of one unit of the baseline BMI after controlling for age, gender, and disease duration.
Commenting on the study, Aaron Miller, MD, FAAN, a professor of neurology at the Icahn School of Medicine at Mount Sinai and medical director of the Corinne Goldsmith Dickinson Center for MS at Mount Sinai Health System, said: “It’s a provocative finding that should lead to additional studies to better understand the nature of the relationship between body weight and MS. But it doesn’t tell us whether the body mass index is actually causing the worsening.
“It could be a marker of a genetic predilection that causes both increased weight and risk of MS,” said Dr. Miller, who was not involved with the study. “The big question is whether improving body mass would have any salutary effect on the course of MS.”
The relationship between weight and MS could be a case of reverse causality and needs to be explored further, said Dalia Rotstein, MD, MPH, an assistant professor of neurology at the University of Toronto.
“Advanced MS can lead to decreased activity which can cause obesity,” Dr. Rotstein said. “There is some evidence that leptin levels may be increased in MS, but again the causal direction of that relationship is unclear.
“I don’t think you can go wrong by recommending a healthy diet to patients," she said. "Without question, comorbidities like diabetes and cardiovascular disease can adversely affect MS progression. But I certainly wouldn’t recommend weight-loss drugs. We really need a stronger evidence base.”
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