The hidden toll: Atrophy of key central nervous system relays in African American women with multiple sclerosis.

BACKGROUND: African American persons with MS (AApwMS) have more aggressive clinical and imaging outcomes than White American pwMS (WApwMS), including lower brain and spinal cord (SC) volumes. However, imaging studies are lacking considering the effects of sex, race, and ethnicity together. OBJECTIVE: Compare MS clinical and imaging features among AApwMS and WApwMS, incorporating the modifying effects of sex, race, and ethnicity. METHODS: Clinical variables and MRI were obtained for AApwMS and WApwMS. RESULTS: Thirty-five MRIs in 28 AApwMS (61 % female) and 255 MRIs in 91 WApwMS (68 % female) were evaluated. AApwMS had a shorter MS disease duration (median 5.9 years, IQR 2.7-13.1) compared to WApwMS (9.4 years, IQR 3.8-17.0; p = 0.034). Fewer AApwMS ever used disease modifying therapy (69 %) compared to WApwMS (92 %; p < 0.001), while the likelihood of having progressive MS and developing severe disability were similar between groups (p > 0.05). AA women with MS had smaller thalamus (p = 0.016), cerebellar grey matter (p = 0.025), and SC-C2 (p = 0.005) volumes than WA women with MS. Although multiple brain and SC regions were smaller in AA men than WA men with MS, the differences were not significant. CONCLUSION: Interaction between sex, race, and ethnicity may influence differences in imaging metrics of key central nervous system relays, likely preceding clinical worsening in MS.