ESPE Abstracts

Background: Vitamin D deficiency can cause rickets and impaired bone growth in infants. In India, randomization to higher vitamin D supplementation doses in pregnancy led to decreased anterior fontanelle and increased head circumference at 0 and 9 months.

Objective and hypotheses: To investigate the impact of cord 25-hydroxyvitamin D (25(OH)D) concentrations on cranial measures.

Method: In a Danish prospective birth cohort of 2549 mother/child pairs, we investigated the association between cord 25(OH)D and infants’ anterior fontanel size (n=766), head shape (n=1528) and head circumference (n=1777). Included were infants between 2.5 and 6 months of age with available cord 25(OH)D and cranial anthropometrics. Excluded were multiples and conditions affecting growth. Fontanel area was calculated from the transverse and longitudinal diameters, head circumference z-scores were generated from national growth charts. 25(OH)D was analyzed using liquid chromatography mass spectrometry. Linear and logistic regression analyses were stratified by prematurity and adjusted for age, sex, smoking, body mass index, educational level, parity, maternal age, skin tone and season of birth.

Results: Mean (S.D.) cord 25(OH)D was 47.1 (21.7) nmol/l, head circumference 41.5 (1.5) cm. At median (IQR) age 3.7 (2.5-6) months, fontanel transverse diameter was 23 (0–58) mm; longitudinal diameter 20 (0–64) mm; area 225 (0–1690) mm². Asymmetric/flat head shape was present in 846 (55.3%). No differences were seen between boys and girls in fontanel size or risk of asymmetric head shape, however boys had significantly larger head circumference than girls. No crude or adjusted associations were found between cord 25(OH)D and any cranial measure.

Conclusion: Cord 25(OH)D is not associated with infant cranial measures in a well-off western population.