Background Salt intake was reported to be associated with increased clinical and MRI activity in adult patients with relapsing-remitting multiple sclerosis (MS).
Objective To determine if salt intake is associated with time to relapse in patients with paediatric-onset MS.
Methods Paediatric-onset MS and patients with clinically isolated syndrome (CIS) within 4 years of disease onset were recruited from 15 paediatric MS centres in the USA as part of a case–control study. Patients with available prospective relapse data subsequent to enrolment were included in this project. Dietary sodium intake was assessed by self-report questionnaire using the validated Block Kids Food Screener. Cox proportional-hazards regression models were employed to determine the association of sodium density, excess sodium intake and sodium density tertiles with time to relapse following study enrolment, adjusting for several confounders.
Results 174 relapsing-remitting MS/CIS patients were included in this analysis (mean age of 15.0 years, and 64.9% females). Median duration of follow-up was 1.8 years. In an unadjusted analysis, density of daily sodium intake was not associated with time to relapse, and patients with excess sodium intake had no decrease in time to relapse as compared with patients with non-excess sodium intake. The multivariable analysis demonstrated that patients in the medium and high tertile of sodium density had a HR of 0.69 (95% CI 0.37 to 1.30, p=0.25) and 1.37 (95% CI 0.74 to 2.51, p=0.32) compared with patients in the lowest tertile, respectively.
Conclusions Higher salt intake was not associated with decreased time to relapse in patients with paediatric-onset MS.
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Contributors BN drafted and edited the manuscript and contributed to the conception and design of the study. TCC performed the statistical analyses, edited the manuscript and contributed to the conception and design of the study. JG, SL, AW, AB, BG, BW-G, GA, J-MT, JH, JN, JR, LK, MG, LB, MR, TC, JR, LB, EW acquired the data, edited and revised the manuscript and contributed to the conception and design of the study. All authors approved the final version of the manuscript.
Funding National Institutes of Health (grant number: R01NS071463-04).
Competing interests BN is a grantee of the National MS Society. This research was conducted while BN was an American Brain Foundation and a Biogen Idec Postdoctoral Fellow. JG was supported by the Foundation for Consortium of Multiple Sclerosis Centers and the NIH Bridging Interdisciplinary Research Careers in Women's Health programmes during this work. She has been a one-time consultant for EMD-Serono. TCC has been supported by the National MS Society and the NIH (R01NS071463). He is an ad-hoc consultant for Biovest International, Inc. EWaubant is funded by the National MS Society, the NIH and the Race to Erase MS. She has received honorarium from Teva Neuroscience and Genzyme for two educational lectures, and is an ad-hoc consultant for Actelion, Sanofi-Aventis and Roche. She is on an advisory board for a clinical trial of Novartis. LK is supported by the National MS Society, NIH, Robert and Lisa Lourie Foundation, Department of Defense. She has received honoraria, consulting payments, grant support or royalties from Biogen, Medimmune, Novartis, Teva Neuroscience, Sanofi-Aventis, and EMD Serono. BW-G received honoraria for serving in advisory boards and educational programmes from Teva Pharmaceuticals, Biogen Idec, Novartis, Accorda EMD Serono, Novartis, Genzyme and Sanofi. She also received support for research activities from the National Institutes of Health, National Multiple Sclerosis Society, National Science Foundation, Department of Defense, EMD Serono, Biogen Idec, Teva Neuroscience, Novartis, Acorda, Genzyme and the Jog for the Jake Foundation. TC has served as a consultant for Biogen-Idec, Teva Neurosciences, Novartis, Sanofi-Aventis, and has received grant support from NIH, National MS Society, Guthy-Jackson Charitable Foundation, CMSC and Merck-Serono and Novartis. JR has research funding from Teva Neuroscience and Biogen. He is a member of the Medical Advisory Board for the DECIDE trial which is funded by Biogen and AbbiV.
Ethics approval Institutional Review Board.
Provenance and peer review Not commissioned; externally peer reviewed.