| Title: | Associations between vitamin D and autoimmune diseases: Mendelian randomization analysis |
| Journal: | Seminars in Arthritis and Rheumatism |
| Published: | 30 Jun 2023 |
| Pubmed: | https://pubmed.ncbi.nlm.nih.gov/37437450/ |
| DOI: | https://doi.org/10.1016/j.semarthrit.2023.152238 |
Publication 11606
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Abstract
OBJECTIVE: The VITAL trial of vitamin D supplementation suggested a possible protective effect for autoimmune diseases but uncertainties remain. We investigated potential causal effects of vitamin D on composite and individual autoimmune diseases using Mendelian randomization.</p>
METHODS: We used data from 332,984 participants of the UK Biobank of whom 23,089 had at least one autoimmune disease defined using ICD code and/or self-report. Diseases were further considered in mechanistic subgroups driven by "autoimmunity" (n = 12,774) or "autoinflammation" (n = 11,164), then individually. We selected variants within gene regions implicated in vitamin D biology to generate a weighted genetic score. We performed population-wide analysis using the ratio method, then examined non-linear effects across five quantiles based on 25-hydroxycholecalciferol levels.</p>
RESULTS: Genetically-predicted vitamin D was associated with lower risk of diseases in the autoinflammation group (OR 0.95 per 10 ng/ml increase in 25-hydroxycholecalciferol; 95%CI 0.91-0.99; p = 0.03) but not the autoimmunity group (OR 0.99; 95%CI 0.95-1.03; p = 0.64) or combined. When considering individual diseases, genetically-predicted vitamin D was associated with lower risk of psoriasis (OR 0.91; 95%CI 0.85-0.97; p = 0.005), the most common disease in the autoinflammation group, and suggestively with systemic lupus erythematosus (OR 0.84; 95%CI 0.69-1.02; p = 0.08); results were replicated using data from independent studies. We found no evidence for a plausible non-linear relationship between vitamin D and any outcome.</p>
CONCLUSIONS: We found genetic evidence to support a causal link between 25-hydroxycholecalciferol concentrations and psoriasis and systemic lupus erythematosus. These results have implications for potential disease prevention strategies, and the interpretation and design of vitamin D supplementation trials.</p>
5 Authors
- Sizheng Steven Zhao
- Amy Mason
- Eva Gjekmarkaj
- Haruyuki Yanaoka
- Stephen Burgess
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