Traumatic brain injury, race, ethnicity and cognition in newly diagnosed persons with multiple sclerosis.

We sought to determine whether a history of traumatic brain injury (TBI) could explain the lower symbol digit modalities test (SDMT) scores observed among newly diagnosed multiple sclerosis (MS) and control participants identifying as Black or Hispanic versus white in the MS Sunshine Study (n = 1172). 330 (29.2 %) participants reported a history of ≥1 TBI. Accounting for TBI did not explain the significant independent associations between having MS, being Black or Hispanic and lower SDMT. The pervasive effects of systemic racism in the United States remain the best explanation for the lower SDMT scores observed in Black and Hispanic participants.