Estimation of the maternal vitamin D intake that maintains circulating 25-hydroxyvitamin D in late gestation at a concentration sufficient to keep umbilical cord sera >= 25-30 nmol/L: a dose-response, double-blind, randomized placebo-controlled trial in pregnant women at northern latitude
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Date
2018
Authors
O'Callaghan, Karen M.
Hennessy, Áine
Hull, George L. J.
Healy, Karina
Ritz, Christian
Kenny, Louise C.
Cashman, Kevin D.
Kiely, Mairead E.
Journal Title
Journal ISSN
Volume Title
Publisher
Oxford University Press
Published Version
Abstract
Background: In the absence of dose-response data, Dietary Reference Values for vitamin D in nonpregnant adults are extended to pregnancy. Objective: The aim was to estimate vitamin D intake needed to maintain maternal 25-hydroxyvitamin D [25(OH)D] in late gestation at a concentration sufficient to prevent newborn 25(OH)D <25-30 nmol/L, a threshold indicative of increased risk of nutritional rickets. Design: We conducted a 3-arm, dose-response, double-blind, randomized placebo-controlled trial in Cork, Ireland (51.9 degrees N). A total of 144 white-skinned pregnant women were assigned to receive 0, 10 (400 IU), or 20 (800 IU) mu g vitamin D-3/d from <= 18 wk of gestation. Vitamin D metabolites at 14, 24, and 36 wk of gestation and in cord sera, including 25(OH)D-3, 3-epi-25(OH)D-3, 24,25(OH)(2)D-3, and 25(OH)D-2 were quantified by liquid chromatography-tandem mass spectrometry. A curvilinear regression model predicted the total vitamin D intake (from diet and antenatal supplements plus treatment dose) that maintained maternal 25(OH)D in late gestation at a concentration sufficient to maintain cord 25(OH)D at >= 25-30 nmol/L. Results: Mean +/- SD baseline 25(OH)D was 54.9 +/- 10.7 nmol/L. Total vitamin D intakes at the study endpoint (36 wk of gestation) were 12.1 +/- 8.0, 21.9 +/- 5.3, and 33.7 +/- 5.1 mu g/d in the placebo and 10-mu g and 20-mu g vitamin D-3 groups, respectively; and 25(OH)D was 24.3 +/- 5.8 and 29.2 +/- 5.6 nmol/L higher in the 10- and 20-mu g groups, respectively, compared with placebo (P < 0.001). For maternal 25(OH)D concentrations >= 50 nmol/L, 95% of cord sera were >= 30 nmol/L and 99% were > 25 nmol/L. The estimated vitamin D intake required to maintain serum 25(OH)D at >= 50 nmol/L in 97.5% of women was 28.9 mu g/d. Conclusions: Thirty micrograms of vitamin D per day safely maintained serum 25(OH)D concentrations at >= 50 nmol/L in almost all white-skinned women during pregnancy at a northern latitude, which kept 25(OH)D at > 25 nmol/L in 99% and >= 30 nmol/L in 95% of umbilical cord sera.
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Keywords
25-hydroxyvitamin D , dietary requirements , dose-response , ODIN , Neonatal , Pregnancy , Randomized controlled trial , Vitamin D , Vitamin D requirements
Citation
O'Callaghan, K. M., Hennessy, Á., Hull, G. L. J., Healy, K., Ritz, C., Kenny, L. C., Cashman, K. D. and Kiely, M. E. (2018) 'Estimation of the maternal vitamin D intake that maintains circulating 25-hydroxyvitamin D in late gestation at a concentration sufficient to keep umbilical cord sera ≥25–30 nmol/L: a dose-response, double-blind, randomized placebo-controlled trial in pregnant women at northern latitude', The American Journal of Clinical Nutrition, 108(1), pp. 77-91. doi: 10.1093/ajcn/nqy064