Vitamin D and Health

serum 25(OH)D concentration in neonates were associated with increased risk of developing
schizophrenia in later life (McGrath et al., 2010b). Serum 25(OH)D concentrations were measured
from dried neonatal blood samples and divided into quintiles: < 19.7, 19.7-30.9, 31-40.4, 40.5-50.9
and > 51 nmol/L. Compared with the 4 th quintile, neonates in the lowest quintile (< 19.7 nmol/L) were
at increased risk of developing schizophrenia (RR=2.1; 95% CI, 1.3-3.5). Neonates in the 2 nd (19.7-
30.9 nmol/L) and 3 rd quintiles (31-40.4 nmol/L) were also at increased risk of developing schizophrenia
(RR=2.0; 95% CI, 1.3-3.2 and RR=2.1; 95% CI, 1.3-3.4 respectively) as were neonates in the highest
quintile (> 51 nmol/L) (RR=1.7; 95% CI, 1.04-2.8).
6.331 A systematic review and meta-analysis of 19 observational studies (8 cross-sectional, 10 case-control;
1 nested case-control) with measures of serum 25(OH)D concentrations in schizophrenic patients
(Valipour et al., 2014) reported that the overall mean difference in serum 25(OH)D concentration
between schizophrenic and control participants was -15 nmol/L (95% CI, -27, -3 nmol/L) but between
study heterogeneity was significant (I 2 =97.6). The overall prevalence of 25(OH)D concentration
< 50 nmol/L in schizophrenic patients was 65% (95% CI, 46-84%); however between study
heterogeneity was significant (I 2 =84.8). Meta-analysis of the odds ratios reported in studies indicated
that individuals with serum 25(OH)D concentration < 50 vs > 50 nmol/L were more likely to have
schizophrenia (OR=2.16; 95% CI, 1.32-3.56).
Summary - Neuropsychological functioning
6.332 RCTs demonstrate no significant effect of vitamin D supplementation on cognition or depression. Evidence
linking vitamin D to cognition and depression is supported mainly by cross-sectional data which suggest an
association between lower 25(OH)D concentration and poor cognitive function. This finding might be due to
reverse causation since changes in cognition and depression may alter diet and/or behaviour in a way which
would reduce serum 25(OH)D concentration.
6.333 Evidence relating vitamin D to autism is very limited and mainly ecological.
6.334 No intervention trials have examined the relationship between vitamin D and schizophrenia. Evidence linking
vitamin D to schizophrenia is mainly ecological. Cross-sectional and case-control studies report that serum
25(OH)D concentration < 50 nmol/L is associated with increased schizophrenia risk; however, 1 case-control
study found that serum 25(OH)D concentration < 20 and > 50 nmol/L is associated with increased schizophrenia
risk.
Oral health
6.335 Vitamin D can impact on oral health by interference in mineralisation of teeth during their
development and by modifying the rate of progression of bone loss during periodontal disease, which
may result in more rapid tooth loss in people with low serum 25(OH)D concentration.
6.336 The impact of vitamin D deficiency on tooth development has been recognised for many years (Dick,
1916) and has been described in both vitamin D dependent rickets (Kikuchi et al., 1988; Zambrano et
al., 2003) and in hypophosphataemic vitamin D resistant rickets (Nishino et al., 1990; Seow et al.,
1995; Goodman et al., 1998; Murayama et al., 2000). Teeth are relatively protected during the
mineralisation phase so effects on teeth are fewer than those seen skeletally. However there are
disturbances of both enamel and dentine formation, that are very similar in the various conditions.
The enamel that develops is hypoplastic, pitted and relatively thin with reduced mineralisation making
the teeth more susceptible to caries. The dentine is abnormal in macroscopic structure and also has
lower than normal levels of mineralisation. Individuals with rickets develop high levels of dental caries
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