MINNEAPOLIS – People who develop multiple sclerosis (MS) as children and grow up in less advantaged neighborhoods may have a larger volume of inflammation and brain tissue loss on imaging than those who grow up in more advantaged neighborhoods, according to a study published in the November 27, 2024, online issue of Neurology® , the medical journal of the American Academy of Neurology .
MS rarely develops in children. About 5% of people with MS are diagnosed before age 18.
In addition to neighborhood location, worse brain imaging outcomes were also seen among people who self-identified as Black or Latino, those from families where the parents had lower education levels, and those who had public health insurance, which is used as a marker of low household income.
"Our findings suggest that social disadvantage in childhood can have lasting effects on MS severity," said study author Kimberly A. O'Neill, MD, of New York University Grossman School of Medicine. "Childhood is a critical time for exposure to environmental factors associated with increased susceptibility to MS, such as passive smoke, pollution and low sunlight exposure. More studies are needed to understand which and how factors in disadvantaged neighborhoods increase the risk for MS severity in young people."
The study involved 138 people with an average age of 20 who were diagnosed with MS before age 18, known as pediatric onset MS. They had been diagnosed with MS for an average of four years.
All had brain scans to measure areas of brain inflammation and injury due to MS and brain volume loss. Researchers collected information on social factors that may impact a person's health, including self-reported race and ethnicity, type of health insurance, parents' education level, and the degree of neighborhood advantage or disadvantage.
Social factors associated with disadvantage correlated with greater volume of inflammatory lesions in the white matter of the brain and also with greater black hole volume, which is a sign of irreversible loss of brain tissue. Together, the identified social factors accounted for 26% of the difference in white matter lesion volume and 23% of the difference in black hole volume among participants.
Once all factors were taken into account, having public health insurance was the strongest predictor of having greater amounts of inflammation and tissue loss. People with public health insurance had average white matter lesion volume that was larger than people with private insurance. They also had average black hole volumes larger than those with private insurance.
The researchers found that the differences were not explained by how soon children were seen by a neurologist, how quickly they were started on medication for MS or how effective their medications were at slowing their disease progress.
"This suggests that access to health care does not explain the more severe disease burden shown in the brain scans of people in disadvantaged groups in our study," O'Neill said. "While these are associations and not causes, many of these groups have historically been underrepresented in MS research and our work here is just beginning."
A limitation of the study is that researchers used the address of the children at the time of their diagnosis but did not have information on any prior addresses. Additionally, only a few types of social factors were studied.
The study was supported by the Lourie Foundation.
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The American Academy of Neurology is the world's largest association of neurologists and neuroscience professionals, with over 40,000 members. The AAN's mission is to enhance member career fulfillment and promote brain health for all. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Alzheimer's disease, stroke, concussion, epilepsy, Parkinson's disease, multiple sclerosis, headache and migraine.
