New research uncovers health changes up to 15 years before multiple sclerosis symptoms appear, opening doors for opportunities to guide prevention and care.
A new study led by Dr. Helen Tremlett, Vancouver Coastal Health Research Institute researcher and professor in the UBC Faculty of Medicine, sheds light on the earliest stages of multiple sclerosis (MS). Published in JAMA Network Open and with funding from the National MS Society and MS Canada, the research team found that the disease process may begin up to 15 years before characteristic symptoms used to make a diagnosis appear.
By analyzing 25 years of health care data from across British Columbia, the study identified subtle early signs of MS that could pave the way for earlier diagnosis and more effective prevention strategies.
Canada has one of the highest rates of MS in the world, with an average of 12 Canadians diagnosed every day. MS is a neurological disease of the central nervous system, affecting the brain, spinal cord and optic nerves. It can cause debilitating symptoms such as cognitive impairment, weakness, vision problems and mood changes, among others.
Previously, most MS research investigated a shorter period before the date of diagnosis and not the earlier date of MS symptom onset.
“This study tells us that MS may start much earlier than previously thought. It’s a key finding that challenges how we think about what causes MS and when we should be looking for it.”
Tremlett’s current study, with UBC postdoctoral fellow Dr. Marta Ruiz-Algueró as first author, examines health care use 25 years before the date of neurologist-determined MS symptom onset. The team found that individuals who later developed MS visited general practitioners much more frequently — reporting issues like fatigue, dizziness, pain and mental health concerns — compared to people who did not develop the disease. These differences began as early as 15 years before symptom onset.
“We now see evidence of the disease process being underway long before symptoms are identified and a diagnosis is made,” says Tremlett.
Identifying early clues in health care usage
The research team accessed comprehensive health administrative data through Population Data BC, which covers the entire provincial population and tracked various types of physician visits in the 25 years leading up to MS symptom onset. Data included MS clinic records of 2,038 patients with MS that were compared with up to five people without MS to study patterns of health care use.
Among the increased health care visits noted were those for general symptoms such as fatigue, pain and depression up to 15 years before symptom onset. Individuals who developed MS also visited psychiatrists more often up to 12 years before symptom onset. Physician specialist visits, including ophthalmology and neurology, increased eight to nine years before symptom onset.
Despite identifying potential early warning signs of MS, Tremlett cautions that these associated symptoms are common and non-specific. "The vast majority of people with these symptoms do not and will not develop MS,” she says. “Our findings are about population patterns, not individual predictions.”
The study extends Tremlett’s earlier research by tracking the prodromal phase of MS over 25 years and using neurologist-confirmed onset dates for more precise timing. “This is probably the earliest point we can define for classical MS onset,” she says.
“Understanding this extended prodromal phase has huge implications for MS prevention and care.”
“If you want to develop prevention strategies, you need to know the right window to target,” Tremlett adds.
Leveraging B.C.’s health data for future research
While limitations remain and the data used was unable to capture more subtle signs or symptoms that didn’t result in a doctor’s visit, Tremlett emphasizes the power of using B.C.’s health data as a resource to uncover the broader picture of MS development. She stresses that these findings reshape how researchers and clinician-scientists approach MS.
“This data enables us to look at health care use on a population-wide scale without what we term ‘recall bias’: when a patient is asked to remember past symptoms after the fact,” says Tremlett. “With access to concrete, objective data, we can identify patterns that individual patients or clinicians might not.”
Tremlett's team recently secured funding from the Canadian Institutes of Health Research to further explore how the prodromal phase in MS compares to other immune-mediated diseases, seeking to identify what is specific to MS and what is common across conditions.
“The opportunity here is to identify MS earlier and to intervene sooner to potentially slow or prevent disease progression,” Tremlett says. “While we are not there yet, this research is an important step toward a future where MS can be detected and managed before disabling symptoms appear.”
