Vitamin D and Health

Evidence considered since IOM report
Intervention studies
6.276 Postmenopausal women (n=36,282) in the Women’s Health Initiative Study of calcium and vitamin D
were randomised to receive vitamin D 3 (10 µg/400 IU) plus calcium (1000 mg) or placebo daily
(Racovan et al., 2012). Over an average of 5 years, 163 new cases of rheumatoid arthritis were
identified (by self-report and validated rheumatic medication use) but there was no difference
between the vitamin D and placebo groups (HR=1.04, 95% CI, 0.76-1.41).
Systemic lupus erythematosus (SLE)
6.277 IOM Report: The IOM did not identify any RCTs or meta-analyses for this indicator. Observational
studies which suggested an association between vitamin D and SLE showed variability in the serum
25(OH)D concentrations associated with SLE. The IOM concluded that the evidence was not sufficient
to permit conclusions being drawn about an association between SLE and serum 25(OH)D
concentration.
6.278 No further studies published after the IOM report, on serum 25(OH)D concentration and risk of SLE,
could be identified.
Summary - Immune modulation
6.279 Evidence from cohort studies on maternal serum 25(OH)D concentration and development of asthma in the
offspring is inconsistent. A systematic review of observational studies reported that conflicting results make it
difficult to establish any clear relationship. Findings from 4 subsequent cohort studies are inconsistent.
6.280 Findings from cohort studies of atopic disorders are inconsistent.
6.281 A large systematic review (219 intervention, prospective and cross-sectional studies) reported that vitamin D
supplementation has little effect on risk of developing autoimmune disease.
6.282 There is a paucity of RCTs on the effect of vitamin D supplementation on development of specific autoimmune
diseases. One RCT reported no effect of vitamin D supplementation during pregnancy on childhood wheezing.
6.283 Evidence to link vitamin D and MS is largely observational and inconsistent. Genetic studies suggest associations
between the ApaI and FokI VDR polymorphisms and MS risk but the role of CYP27B1 in the development of MS is
unclear.
6.284 Data are lacking on the relationship between vitamin D and type 1 diabetes, inflammatory bowel disease,
rheumatoid arthritis and SLE.
Infectious diseases
6.285 A possible role of vitamin D in modulating the immune response has been suggested by the presence
of VDRs and 1α-hydroxylase (CYP27B1) in various cells of the immune system including B and T
lymphocytes, macrophages and dendritic cells. Cell studies have shown that vitamin D enhanced
bactericidal activity of human macrophages against Mycobacterium tuberculosis (Crowle et al., 1987).
Liu et al. (2006) reported that TLR activation of human macrophages upregulated expression of the
VDR and 1α-hydroxylase genes, leading to induction of the antimicrobial peptide cathelicidin and
restricting growth of intracellular M tuberculosis. It has been proposed that in vitamin D deficiency,
the infected macrophage is unable to produce sufficient 1,25(OH) 2 D to upregulate production of
cathelicidin.
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