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Free vitamin D 3 index and vitamin D‐binding protein in multiple sclerosis: A presymptomatic case–control study
Author(s) -
Grut Viktor,
Biström Martin,
Salzer Jonatan,
Stridh Pernilla,
Lindam Anna,
AlonsoMagdalena Lucia,
Andersen Oluf,
Jons Daniel,
Gunnarsson Martin,
Vrethem Magnus,
Hultdin Johan,
Sundström Peter
Publication year - 2022
Publication title -
european journal of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 124
eISSN - 1468-1331
pISSN - 1351-5101
DOI - 10.1111/ene.15407
Subject(s) - medicine , multiple sclerosis , vitamin d and neurology , vitamin , vitamin d binding protein , index (typography) , immunology , world wide web , computer science
Background and purpose High levels of 25‐hydroxyvitamin D 3 (25[OH]D 3 ) are associated with a lower risk for multiple sclerosis (MS). The bioavailability of 25(OH)D 3 is regulated by its main plasma carrier, vitamin D‐binding protein (DBP). Free 25(OH)D 3 can be estimated by also measuring DBP concentration. In addition, DBP has immunomodulatory functions that may independently affect MS pathogenesis. No previous studies have assessed free 25(OH)D 3 or DBP in presymptomatically collected samples. This study was undertaken to assess free 25(OH)D 3 and DBP as risk factors for MS. Methods A nested case–control study was performed with presymptomatic serum samples identified through cross‐linkage of MS registries and Swedish biobanks. Concentration of 25(OH)D 3 was measured with liquid chromatography and DBP levels with sandwich immunoassay. Free 25(OH)D 3 was approximated as free vitamin D 3 index: (25[OH]D 3 /DBP) × 10 3 . MS risk was analyzed by conditional logistic regression, calculating odds ratios (ORs) with 95% confidence intervals (CIs). Results Serum samples from 660 pairs of matched cases and controls were included. At <20 years of age, high levels of free vitamin D 3 index were associated with a lower risk of MS (highest vs. lowest quintile: OR = 0.37, 95% CI = 0.15–0.91, p for trend across quintiles = 0.04). At age 30–39 years, high levels of DBP were associated with a lower MS risk (highest vs. lowest quintile: OR = 0.36, 95% CI = 0.15–0.85, p for trend = 0.02). Conclusions These findings support the hypothesis that high levels of free 25(OH)D 3 at a young age reduce the risk of MS later in life. They also implicate a role for DBP in MS etiology.