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bioRxiv · 10.1101/584888

Accelerated brain ageing and disability in multiple sclerosis

Abstract

BackgroundBrain atrophy occurs in both normal ageing and in multiple sclerosis (MS), but it occurs at a faster rate in MS, where it is the major driver of disability progression. Here, we employed a neuroimaging biomarker of structural brain ageing to explore how MS influences the brain ageing process.\n\nMethodsIn a longitudinal, multi-centre sample of 3,565 MRI scans in 1,204 MS/clinically isolated syndrome (CIS) patients and 150 healthy controls (HCs) (mean follow-up time: patients 3*41 years, HCs 1*97 years) we measured brain-predicted age using T1-weighted MRI. Brain-predicted age difference (brain-PAD) was calculated as the difference between the brain-predicted age and chronological age. Positive brain-PAD indicates a brain appears older than its chronological age. We compared brain-PAD between MS/CIS patients and HCs, and between disease subtypes. In patients, the relationship between brain-PAD and Expanded Disability Status Scale (EDSS) at study entry and over time was explored.\n\nFindingsAdjusted for age, sex, intracranial volume, cohort and scanner effects MS/CIS patients had markedly older-appearing brains than HCs (mean brain-PAD 11*8 years [95% CI 9*1--14*5] versus -0*01 [-3*0--3*0], p<0*0001). All MS subtypes had greater brain-PAD scores than HCs, with the oldest-appearing brains in secondary-progressive MS (mean brain-PAD 18*0 years [15*4--20*5], p<0*05). At baseline, higher brain-PAD was associated with a higher EDSS, longer time since diagnosis and a younger age at diagnosis. Brain-PAD at study entry significantly predicted time-to-EDSS progression (hazard ratio 1*02 [1*01--1*03], p<0*0001): for every 5 years of additional brain-PAD, the risk of progression increased by 14*2%.\n\nInterpretationMS increases brain ageing across all MS subtypes. An older-appearing brain at baseline was associated with more rapid disability progression, suggesting brain-age could be an individualised prognostic biomarker from a single, cross-sectional assessment.\n\nFundingUK MS Society; National Institute for Health Research University College London Hospitals Biomedical Research Centre.

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BibTeXRIS

Cole, J. H., Raffel, J., Friede, T., Eshaghi, A., Brownlee, W., Chard, D., De Stefano, N., Enzinger, C., Pirpamer, L., Filippi, M., Gasperini, C., Rocca, M. A., Rovira, A., Ruggieri, S., Sastre-Garriga, J., Stromillo, M. L., Uitdehaag, B., Vrenken, H., Barkhof, F., Ciccarelli, O., Nicholas, R.. 2019-03-21. Accelerated brain ageing and disability in multiple sclerosis. https://doi.org/10.1101/584888

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