African Amercian MSers show more nerve loss than European American MSers?

Kimbrough DJ, Sotirchos ES, Wilson JA, Al-Louzi O, Conger A, Conger D, Frohman TC, Saidha S, Green AJ, Frohman EM, Balcer LJ, Calabresi PA.Retinal Damage and Vision Loss in African-American Multiple Sclerosis Patients. Ann Neurol. 2014 Nov 8. doi: 10.1002/ana.24308. [Epub ahead of print]#

Objective: To determine whether African-American (AA) multiple sclerosis (MS) patients exhibit more retinal damage and visual impairment compared to Caucasian-American (CA) MS patients. Methods: 687 MS patients (81 AA) and 110 healthy control (HC) subjects (14 AA) were recruited at three academic hospitals between 2008 and 2012. Using mixed effects regression models, we compared high and low contrast visual acuity (HCVA and LCVA) and high-definition spectral-domain optical coherence tomography (Cirrus-OCT) measures of retinal architecture between MS patients of self-identified AA and CA ancestry. 

Results: In HC, baseline peripapillary retinal nerve fiber layer thickness (RNFL) was 6.1 μm greater in AA (p = 0.047), while ganglion cell / inner plexiform layer (GCIP) thickness did not differ by race. In MS patients, baseline RNFL did not differ by race, and GCIP was 3.98 µm thinner in AA (p = 0.004). AA had faster RNFL and GCIP thinning rates compared to CA (p = 0.004 and p= 0.046, respectively). AA MS patients had lower baseline HCVA (p = 0.02) and worse LCVA per year of disease duration (p= 0.039). Among patients with an acute optic neuritis (AON) history, AA had greater loss of HCVA than CA patients (p = 0.012). 
Interpretation: This multicenter investigation provides objective evidence that AA MS patients exhibit accelerated retinal damage compared to CA MS patients. Self-identified AA ancestry is associated with worse MS-related visual disability, particularly in the context of an AON history, suggesting a more aggressive inflammatory disease course among AA MS patients or a subpopulation therein.
This study looks in eyes of black Americans and finds more evidence of nerve damage than found in White Americans. This is consistent with the finding that black AmerIcans and Europeans tend to develop Progressive MS compared to White Europeans, which suggests that there may be some genetic of physiological effect, that results in less toleration of inflammatory damage that results nerve damage.

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