Nerve damage marker linked to lower daily activity in progressive MS
Study finds higher NfL scores line up with steady declines in step counts
Written by |
Higher blood levels of neurofilament light chain, a marker of nerve damage, are associated with lower daily activity in people with progressive forms of multiple sclerosis, a study found.
- Higher blood levels of the nerve damage marker NfL are linked to reduced daily physical activity in progressive MS.
- Study participants whose NfL levels increase more rapidly over time tended to experience greater declines in daily step counts.
- A reverse association was also observed, with a 10% increase in daily steps tied to 0.015-point lower NfL z-score.
Higher blood levels of neurofilament light chain (NfL), a well-established marker of nerve damage, are associated with lower daily activity in people with progressive forms of multiple sclerosis (MS), a study found.
The study also demonstrated that patients in whom NfL levels increased more rapidly over time tended to experience greater declines in daily activity, as measured by the number of daily steps using a wearable device.
The findings suggest that “reduced daily physical activity is associated with greater ongoing tissue injury measured by [NfL], and vice versa,” researchers wrote.
The study, “Association Between Neurofilament Light Chain and Real-World Ambulatory Function in Progressive MS,” was published in Annals of Clinical and Translational Neurology.
Study explored potential link between NfL levels and mobility
MS is caused by the immune system mistakenly attacking nerve cells in the brain and spinal cord. NfL is a protein found in nerve fibers that is released into the bloodstream when these fibers are damaged, so measuring NfL in blood can help researchers track nerve injury in people with MS. However, how changes in NfL levels relate to patients’ mobility has been less clear.
To investigate this, researchers at the University of California, San Francisco conducted an analysis of data from the Phase 3 SPI2 trial (NCT02936037), which evaluated high-dose biotin against a placebo in people with progressive MS, but found no significant differences in disease progression.
As part of the trial, participants’ daily step counts were assessed using a wearable device, and their NfL levels were also measured at multiple visits over time. The current analysis included 506 participants who had at least one blood NfL measurement paired with a daily step-count measurement during the study.
The participants had a mean age of 52.7 years, and 53.8% were women. Most had secondary progressive MS (64.4%), while the remaining 35.6% had primary progressive MS. Their median score on the Expanded Disability Status Scale, a measure of MS-related disability, was 6, which indicates a need for a walking aid.
Reverse association also observed
At the first available assessment, participants had a median of 3,029 daily steps. Their mean blood NfL z-score was 1. A z-score compares a person’s NfL level with reference values from healthy people, adjusted for factors such as age and body mass index, a measure of body fat based on weight and height. A score of 1 means the level was one standard deviation above the reference value for a matched healthy population.
Over the 27-month study period, higher blood NfL z-scores were associated with lower daily step counts. Specifically, each 1-point increase in the NfL z-score was associated with approximately 3.4% fewer daily steps.
The reverse association was also observed, with a 10% increase in daily steps being linked to a 0.015-point lower NfL z-score. These associations remained consistent across sex, disability level, trial treatment, and use of disease-modifying therapies.
Throughout the study, NfL levels increased among participants whose daily step counts declined by at least 15%, while they remained relatively stable among those whose step counts increased by at least 15%. However, the difference between groups did not reach statistical significance.
Higher [NfL] was associated with reduced daily ambulatory activity in progressive MS, and vice versa.
The researchers next examined whether changes in NfL preceded changes in daily activity. In an analysis comparing NfL changes during the first six months with changes in step counts during the following six months, greater increases in NfL tended to be associated with subsequent declines in daily steps. However, this association also did not reach statistical significance.
In a separate analysis of individual changes over the full study period, participants whose NfL levels increased more rapidly tended to experience greater declines in daily step counts. This association was statistically significant, although it was modest.
“Higher [NfL] was associated with reduced daily ambulatory activity in progressive MS, and vice versa,” the researchers wrote, adding that “these findings justify further exploration of the use of both biological and functional measures to detect MS progression in clinical and rehabilitation trials.”
However, the team noted that these findings may not apply to people with lower disability levels or other forms of MS.
Leave a comment
Fill in the required fields to post. Your email address will not be published.