Gestational vitamin D and offspring risk of multiple sclerosis: a systematic review and meta-analysis

Abstract

Purpose: Our objective was to systematically review and meta-analyze studies that assessed the association between gestational vitamin D levels and risk of multiple sclerosis (MS) in offspring. Methods: Embase and Pubmed databases were searched from inception to May 2018. Original, observational studies that investigated both clinically defined MS (in offspring) and vitamin D levels in utero or shortly after birth were included. Two reviewers independently abstracted data and assessed the quality of studies using the Newcastle-Ottawa Quality Assessment Scale. Summary effect estimates and 95% confidence intervals were calculated with random effects models using inverse variance weighting. Determinants of heterogeneity were evaluated. Results: Four case-control studies of moderate to low risk of bias were included. Summary effect estimates of the effect of higher levels of gestational vitamin D on risk of offspring MS demonstrated a significant protective effect in random effects (OR: 0.63, 95% CI: 0.47, 0.84) models and in a stratified analysis based on study quality. Factors identified as determinants of heterogeneity were the definitions of vitamin D deficiency, the characteristics of study participants, and the quality of the study. Conclusions: Sufficient levels of vitamin D during pregnancy may be protective against offspring's development of multiple sclerosis later in life.