MS in Black Americans: Research Challenges Old Beliefs

Until recently, much of the medical community believed that multiple sclerosis (MS) was far less common among Black Americans than in the white population. This misconception became something of a self-fulfilling prophecy: Believing that MS was uncommon in this group, doctors would often unintentionally misdiagnose Black people who actually had MS, which in turn led to a low measured rate of MS — and widespread inappropriate and ineffective treatment.

This isn’t the first or only time that false beliefs about multiple sclerosis have held powerful sway, says Nicholas LaRocca, PhD, a psychologist and consultant for the National Multiple Sclerosis Society.

“In the 1920s, it was thought that MS was a vascular disease or that it was caused by some sort of psychological or emotional weakness,” Dr. LaRocca says.

But just as research has shown those ideas to be incorrect, large, well-run studies have shown that Black people definitely do develop MS, perhaps as frequently as or even more frequently than white people.

A& study published in May 2013 in the journal Neurology that used patient records from the Kaiser Permanente Southern California health plan, for example, found a higher incidence of MS among Black patients than among white, Hispanic, or Asian patients.

Similarly, a study published in June 2012 in the journal Brain that was conducted by the U.S. Department of Veterans Affairs found that among U.S. military veterans, Black people had the highest incidence of MS out of all races and ethnicities in the study group.

Still, exactly how common MS is among Black Americans remains a matter of debate, in part because researchers have only just begun to investigate this question, and in part because the complex causes of MS mean that the incidence of disease is likely to vary from one study population to another. For example, an article published in March 2019 in the journal Neurology found that overall, MS was 38 percent more prevalent in the Northeast than in the South of the United States.

Causes of MS Complex Across Groups

Diverse factors contribute to the onset of MS, including genetics and environmental influences, such as geography. A person’s risk for MS increases the farther that person lives from the equator. For example, light-skinned Scandinavians are at much higher MS risk than dark-skinned Africans.

One reason geography affects MS risk is that people who live in cold climates far from the equator are less likely to expose their skin to sunlight, and the sun’s rays are what enable human bodies to produce vitamin D. Inhabitants of cold Northern zones consequently tend to have lower blood levels of vitamin D, and such a deficiency is a risk factor for multiple sclerosis.

But the intersection of race, sun exposure, and vitamin D levels shows just how complicated the onset of MS is. In a study published in February 2018 in the journal Nutrients, researchers found that higher lifetime exposure to ultraviolet light — a measure of sun exposure — was associated with a lower risk of MS in both Black and white people, independent of vitamin D levels. Higher blood levels of vitamin D were associated with a lower risk of MS in white people only.

Meanwhile, MS genetics are complex, with as many as 200 different genes involved, says Bruce Cree, MD, a neurologist and clinical research director at the UCSF Multiple Sclerosis Center in San Francisco. Dr. Cree has been deeply involved in research on the genetic causes of MS.

One gene, called HLA-DRB1, plays an outsize role in the onset of MS. Variants of HLA-DRB1 show up in genetic profiles of MS patients of Northern European ancestry, and related variants show up in profiles of Black Americans with MS.

Both Cree and LaRocca emphasize that the genetic makeup of nearly all Black Americans reflects a mixture of ethnic groups. Due to the history of slavery in the United States, Black Americans often have Northern European ancestors. They may also have Native American or Asian forebears.

To better understand the role of genetics in the development and progression of MS, the UCSF Multiple Sclerosis Genetics Project is recruiting Black Americans on an ongoing basis to participate in the African American Study arm of the project. “The study has had a number of challenges with recruitment throughout the years,” says Cree. “We’re still very interested in having people of African descent with MS participate.”

Several articles have already been published based on the data from this ongoing study, including one, published in August 2019 in the Multiple Sclerosis Journal, that examined the relevance of genetic risk factors for MS — which have been established mostly based on studying people of European ancestry — in African American and Hispanic populations in the United States.

MS Often More Severe in Black Americans

Based on his research, Cree estimates that compared with people of Northern European ancestry in the United States, those of African ancestry develop MS at about half the rate. But Black Americans tend to develop more aggressive forms of MS than white Americans do.

“We see greater motor impairment and a larger percentage of African American patients with spinal involvement,” says Cree, which indicates a more aggressive form of illness. A study published in November 2016 in the Multiple Sclerosis Journal found that after adjusting for differences in age and gender, MS severity scores — on a scale of 0 to 10 — were 1.1 points higher, on average, among African Americans than among Caucasian Americans.

Another study, published in July 2010 in the journal Neurology, found that African Americans were more likely to belong to higher tiers of an MS severity score and less likely to belong to lower tiers than white Americans. With six different tiers of MS severity, 41.5 percent of cases among African Americans fell in the top two tiers, compared with 29.3 percent of cases among white Americans. The two lowest tiers had 23.4 percent of cases among African Americans, compared with 35.4 percent of cases among white Americans.

A more recent study, published in November 2018 in the journal Brain, found that both brain and retinal (eye) atrophy happened faster in African Americans than in Caucasian Americans with MS. African Americans tended to lose gray brain matter at a rate of 0.9 percent per year and white matter at 0.7 percent per year, compared with 0.5 percent and 0.3 percent for Caucasian Americans. While 12.1 percent of African Americans showed microcystoid degeneration in their eyes, only 0.9 percent of Caucasian Americans did, and atrophy of retinal nerve fibers and other cells was shown to proceed at a faster rate.

Yet another study, published in February 2018 in the journal Neurologic Clinics, found that African Americans with MS were more likely than Caucasians to have disease involving the eyes or spinal cord, both of which predict greater disability. This greater tendency toward disability is also related to lower access to healthcare in general, and MS specialists in particular, among African Americans and other minority groups, the study noted.

MS Therapies for Black Americans

In general, studies have suggested that the MS treatments that work better for Caucasians also work better for African Americans, although the evidence is limited in this area. For example, interim results of a real-world study of Tecfidera (dimethyl fumarate), presented in June 2019, showed that the drug was safe and effective in African American and Black people with relapsing-remitting MS — something that original clinical trials of the drug couldn’t show, since they didn’t include enough Black participants.

For Sharon Froston, 55, a Black woman who lives in Boston and was diagnosed with MS 13 years ago, newer disease-modifying medications for MS have kept her illness under control.

“I currently take an oral medication called Aubagio (teriflunomide) once a day, and it works well for me, without any side effects,” says Froston. Before starting Aubagio, Froston went monthly to an MS center for Tysabri (natalizumab) infusions. Unsurprisingly, she prefers the pills.

Importantly, though, Black Americans have generally been largely absent from clinical trials for MS treatments. “In some pivotal trials, there were literally fewer than 10, and in other studies, fewer than five” participants, says Cree. Such underrepresentation of Black Americans in clinical trials must change, both Cree and LaRocca agree.

But recruitment can be a challenge when it comes to including Black people and other minority groups in clinical trials, says Jagannadha “Jay” Avasarala, MD, a neurologist and MS specialist at UK Kentucky Neuroscience Institute in Lexington. Dr. Avasarala wrote an article, published in January 2019 in the journal CNS Spectrums, that recommends adding disclaimers to published articles as well as to drug package inserts when clinical trials don’t include enough participants from racial and ethnic minority groups. Drug companies, he writes, should also collect data on efficacy in minority groups once a treatment is in widespread use, and report this data to the U.S. Food and Drug Administration (FDA).

Looking at African American participation in two clinical trials of MS drugs a decade apart, “what shocked me was that the numbers dropped from 11 percent to 2 percent,” says Avasarala. “That was unacceptable to me.” Having data to support a drug’s efficacy in this population matters, he says, because of the documented differences in MS progression and disease burden compared with other groups.

Getting adequate Black participation in MS drug trials, Avasarala says, might require drug companies stepping up their recruitment efforts, the FDA pressuring or requiring drug companies to include more minorities in clinical trials, and Black Americans themselves participating more. “I don’t know if there is an easy fix,” he adds.

Ocrevus Potentially Important for Black Americans With MS

In March 2017, the FDA approved Ocrevus (ocrelizumab), the first drug ever approved for primary-progressive MS. Ocrevus is given as an intravenous infusion in a clinic or doctor’s office twice a year, and appears to have only mild side effects for most people. It is also effective as a treatment for relapsing MS.

The approval of a drug for primary-progressive MS “is especially important for African Americans,” says Cree, “since they tend to have progressive forms of MS to a greater extent than white people.” Because of the faster progression and greater disease burden that Black people with all forms of MS often experience, Cree notes, it’s especially important for this group to receive an effective treatment promptly, “perhaps earlier in the disease course” than might be considered for white people.

Since its FDA approval, Ocrevus has been the subject of ongoing research, which has shed light on its effectiveness in Black people with MS. Cree notes that within a subgroup of 72 participants of African descent in a clinical trial, the drug showed benefits similar in scale to those seen in the overall study group.

That includes being just as effective at preventing relapses and disability, says Cree, although these trends weren’t statistically significant because of the small number of African American participants. But Ocrevus was shown to significantly reduce new MS lesion formation, as well as lead to the composite outcome of “no evidence of disease activity,” over the alternative treatment in the trial, Rebif (interferon beta-1a). Overall, says Cree, “there seemed to be a robust effect of treatment favoring use of ocrelizumab.”

Recognizing Symptoms and Getting Help

It’s important for anyone at risk of developing MS — including Black people — to recognize its symptoms so that treatment can be started early, when it’s most effective.

Getting a definitive diagnosis of MS can often take some time for anyone, regardless of race, because many of the symptoms of MS resemble those of other diseases.

Froston’s first symptom was double vision, which wasn't immediately recognized as MS. The eye drops she used for her vision problem helped, but when other symptoms, including tingling in her fingers, arose and she mentioned them to her dentist, he referred her to a neurologist, who correctly diagnosed MS.

Because of socioeconomic differences, Black Americans often have less access to the best care for MS and other health conditions. But no matter your background, if you suspect that you or a loved one may have MS and you need advice or assistance, you can contact the National MS Society, where an MS Navigator can guide you to appropriate medical care and other resources in your area.

Additional reporting by Quinn Phillips.