Vitamin D and Health

6.251 VDRs are expressed in cells of the immune system (e.g., lymphocytes, macrophages, natural killer
cells) suggesting that vitamin D may have immunomodulatory effects. Low serum 25(OH)D
concentration has been associated with allergic conditions (e.g., asthma and atopic conditions) and
autoimmune diseases. It has been proposed that vitamin D may play a role in the development of
allergic and autoimmune disease based on ecological data reporting greater prevalence of these
diseases in Northern latitudes where sun exposure is lower (Ponsonby et al., 2002; Staples et al.,
2003).
6.252 Autoimmune disease is caused by a dysfunction of the body’s immune system and is mediated by T or
B cell activation leading to tissue damage. The aetiology and pathogenesis of most autoimmune
disorders remains unknown and several factors have been implicated in their development. A number
of epidemiological studies have reported an association between low serum 25(OH)D concentration
and asthma and atopic disorders as well as several autoimmune disorders including inflammatory
bowel disease, multiple sclerosis, rheumatoid arthritis and systemic lupus erythematosus (Kriegel et
al., 2011; Antico et al., 2012).
6.253 IOM Report: The IOM considered evidence on asthma and autoimmune disease (type I diabetes,
inflammatory bowel and Crohn’s disease, multiple sclerosis, rheumatoid arthritis and systemic lupus
erythematosus). It concluded that, overall, the evidence was not consistently supportive of a causal
role for vitamin D in reducing risk of asthma or autoimmune disease.
Evidence considered since IOM report (Tables 46-49, Annex 2)
Systematic reviews and meta-analyses
6.254 A systematic review of 219 studies (cross-sectional, intervention and prospective) examined whether
serum 25(OH)D concentration was related to the risk of developing autoimmune disease and whether
vitamin D supplementation could modify its progress (Antico et al., 2012). Most of the studies were of
patients with pre-existing autoimmune disease; only 2 prospective cohort studies examined
correlations between serum 25(OH)D concentration and risk of developing autoimmune disease. Out
of these, 1 (Nielen et al., 2006) found no correlation between serum 25(OH)D concentration and risk
of developing rheumatoid arthritis while the other (Munger et al., 2006) found an inverse association
between risk of developing multiple sclerosis and serum 25(OH)D concentration in white participants
only (OR per 50 nmol/L increase=0.59; 95% CI, 0.36-0.97). The authors concluded that although
genetic and epidemiological studies suggest a potential role of vitamin D in the prevention of
autoimmune diseases there was little evidence of benefit from vitamin D supplementation.
Asthma and atopic disorders
Intervention studies
6.255 A randomised trial examined the effect of prenatal vitamin D supplementation on childhood wheezing
(Goldring et al., 2013). Pregnant women (n=180; at 27 weeks gestation) were randomised to receive
either vitamin D 2 (20 µg/800 IU daily), a single dose of vitamin D 3 (5000 µg/200,000 IU), or no vitamin
D. There was no significant difference between groups in risk of wheeze at 3y of age (HR=0.86; 95%
CI, 0.49-1.50; p=0.69).
Cohort studies
6.256 A systematic review on the effects of vitamin D supplementation in pregnancy on multiple maternal
and childhood health outcomes, which identified 8 observational studies assessing relationships
between maternal vitamin D intake during pregnancy (n=4), maternal serum 25(OH)D concentration in
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