Vitamin D and Health

Summary - Pregnancy & lactation
Bone health indices
Maternal outcomes
6.61 One small cohort study reported a negative correlation between maternal serum 25(OH)D concentration and a
marker of bone resorption (CTX concentration) in the 2 nd and 3 rd trimesters of pregnancy and the postpartum
period.
Fetal/newborn outcomes
6.62 One large RCT in the UK reported no overall effect of vitamin D supplementation during pregnancy on BMC,
BMD or bone area in the newborn infant but a significantly lower BMC, BMD and bone area in infants born to
non-supplemented mothers in the winter (December-February).
6.63 Out of 5 cohort studies, 4 show a positive association between maternal serum 25(OH)D concentration and
various indices of bone health in the fetus/newborn. Three studies chose pre-determined cut-offs to define
vitamin D deficiency (< 50 nmol/L in 2 studies and 42.6 nmol/L in 1 study).
Infants (up to 12 months)
Bone health indices
6.64 IOM report: The IOM reported inconsistent evidence for an association between serum 25(OH)D
concentration and BMC in infants. Out of 2 RCTs examining the effects of vitamin D supplementation
on BMC (Greer et al., 1981; Zeghoud et al., 1997), 1 reported no effect of an increase in serum
25(OH)D concentration on radial bone mass while the other reported a transient increase of BMC in
the supplemented group compared with the unsupplemented group at 12 weeks but not at 26 weeks.
Evidence from case control studies suggested an association between greater whole body BMC and
higher serum 25(OH)D concentration.
Evidence considered since IOM report (Table 10, Annex 2)
Intervention studies
6.65 A study in South Korea (Kim et al., 2010) examined the effect of daily vitamin D supplementation
(10 µg/400 IU for 12 months) on BMD in breast-fed infants (n=74) at 6 and 12 months of age. Vitamin
D supplementation significantly increased serum 25(OH)D concentration but not BMD. However,
there are a number of uncertainties in this paper which include use of BMD rather than BMC or BMAD
in growing children and not providing data on power calculations for the sample size required to
detect a bone density difference with treatment.
6.66 A study in India (Kumar et al., 2011) investigated the effect of vitamin D 3 supplementation
(35 µg/1400 IU per wk for 6 months) on growth (secondary outcome 44 ) in low birth weight term
infants (n=2070; age, ≤ 48 hours). After 6 months, mean serum 25(OH)D concentration was 55 nmol/L
in the supplemented group and 36 nmol/L in the placebo group. Vitamin D supplementation
significantly increased z scores at 6 months for weight (p=0.026), length (p=0.014) and arm
circumference (p=0.033) and significantly reduced the proportion of children with stunted growth
(p=0.018). However, findings from this study should be interpreted with caution since there was a
44 Primary outcomes were mortality and morbidity.
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