1. 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.
- Author
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O'Callaghan, Karen M, Hennessy, Áine, Hull, George L J, Healy, Karina, Ritz, Christian, Kenny, Louise C, Cashman, Kevin D, and Kiely, Mairead E
- Subjects
RICKETS prevention ,VITAMIN D deficiency ,CORD blood ,NUTRITIONAL requirements ,PROBABILITY theory ,REGRESSION analysis ,STATISTICAL sampling ,VITAMIN D ,CHOLECALCIFEROL ,RANDOMIZED controlled trials ,BLIND experiment ,DESCRIPTIVE statistics ,CHILDREN ,PREGNANCY ,PREVENTION - Abstract
Background: In the absence of dose-response data, Dietary ReferenceValues for vitaminDin 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°N). A total of 144 white-skinned pregnant women were assigned to receive 0, 10 (400 IU), or 20 (800 IU) µg 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)D3 , 3-epi-25(OH)D3 , 24,25(OH)2 D3 , and 25(OH)D2 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 µg/d in the placebo and 10-µg and 20-µg vitamin D3 groups, respectively; and 25(OH)D was 24.3 ± 5.8 and 29.2 ± 5.6 nmol/L higher in the 10- and 20-µg 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 µg/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. This trial was registered at www.clinicaltrials. gov as NCT02506439. [ABSTRACT FROM AUTHOR]- Published
- 2018
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