Multiple sclerosis 43% less likely in child if an average of 330 IU of vitamin D was taken while pregnant - Nov 2025
Vitamin D intake and multiple sclerosis risk in the Norwegian Mother, Father and Child cohort
J Neurol Neurosurg Psychiatry . 2025 Nov 28 doi: 10.1136/jnnp-2025-337300 PDF behind paywall
Akash Kapali 1 2, Anne Kjersti Daltveit 1 3, Kjell-Morten Myhr 2 4, Kjetil Bjornevik 5 6, Karine Eid 4 7, Marte-Helene Bjørk 4 7, Anne Lise Brantsæter 8 9, Trond Riise 1 2, Marianna Cortese 10
Background: Higher vitamin D has consistently been associated with a lower multiple sclerosis (MS) risk, but some controversy remains about whether this is due to vitamin D itself or sunlight.
Methods: We conducted a prospective study among women participating in the Norwegian Mother, Father and Child Cohort Study, recruited in 2002-2008 and followed until 2022. We identified incident MS cases through data linkage with the Norwegian MS Registry. Total vitamin D intake from food and supplements was obtained from validated food frequency questionnaires completed in pregnancy. We estimated HRs for MS and 95% confidence intervals (CI) using Cox regression.
Results: Among 78,074 participants, 349 developed MS during follow-up. Their median daily vitamin D intake was 296 international units (IU) compared with 333 IU among women who did not develop MS. Higher total vitamin D intake was associated with a 42% lower MS risk (HR comparing top vs bottom quintile 0.58, 95% CI 0.38 to 0.89, ptrend<0.01). The results were similar when adjusting for age at delivery, total energy intake, pre-pregnancy body mass index and smoking. The associations were similar for vitamin D intake from food (HR for top vs bottom quintile 0.70, 95% CI 0.47 to 0.1.04, ptrend=0.02) and supplements (HR for ≥600 IU/day vs <200 IU/day 0.65, 95% CI 0.41 to 1.04, ptrend=0.01).
Conclusions: In this prospective study, higher vitamin D intake was associated with lower MS risk in women living in Norway, where there is insufficient sun-induced vitamin D production during most of the year. This supports the hypothesis that vitamin D itself modifies MS risk.
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