Exploring the concept of functional vitamin D deficiency in pregnancy: impact of the interaction between 25-hydroxyvitamin D and parathyroid hormone on perinatal outcomes

Loading...
Thumbnail Image
Date
2018
Authors
Hemmingway, Andrea
Kenny, Louise C.
Malvisi, Lucio
Kiely, Mairead E.
Journal Title
Journal ISSN
Volume Title
Publisher
Oxford University Press
Published Version
Research Projects
Organizational Units
Journal Issue
Abstract
Background: Associations of vitamin D with perinatal outcomes are inconsistent and few studies have considered the wider calcium metabolic system. Objectives: We aimed to explore functional vitamin D deficiency in pregnancy by investigating associations between vitamin D status, parathyroid hormone (PTH), and perinatal outcomes. Design: SCOPE (Screening for Pregnancy Endpoints) Ireland is a prospective cohort study of low-risk, nulliparous pregnant women. We measured serum 25-hydroxyvitamin D [25(OH)D] and PTH at 15 wk of gestation in 1754 participants. Results: Mean ± SD 25(OH)D was 56.6 ± 25.8 nmol/L (22.7 ± 10.3 ng/mL) and geometric mean (95% CI) PTH was 7.84 pg/mL (7.7, 8.0 pg/mL) [0.86 pmol/L (0.85, 0.88 pmol/L)]. PTH was elevated in 34.3% of women who had 25(OH)D <30 nmol/L and in 13.9% of those with 25(OH)D ≥75 nmol/L. Whereas 17% had 25(OH)D <30 nmol/L, 5.5% had functional vitamin D deficiency, defined as 25(OH)D <30 nmol/L with elevated PTH. Elevated mean arterial pressure (MAP), gestational hypertension, pre-eclampsia, and small-for-gestational-age (SGA) birth were confirmed in 9.2%, 11.9%, 3.8%, and 10.6% of participants, respectively. In fully adjusted regression models, neither low 25(OH)D nor elevated PTH alone increased the risk of any individual outcome. The prevalence of elevated MAP (19.1% compared with 9.7%) and SGA (16.0% compared with 6.7%) were highest (P < 0.05) in those with functional vitamin D deficiency compared with the reference group [25(OH)D ≥75 nmol/L and normal PTH]. The adjusted prevalence ratio (PR) and RR (95% CIs) for elevated MAP and SGA were 1.83 (1.02, 3.27) and 1.53 (0.80, 2.93), respectively. There was no effect of functional vitamin D deficiency on the risk of gestational hypertension (adjusted RR: 1.00; 95% CI: 0.60, 1.67) or pre-eclampsia (adjusted RR: 1.17; 95% CI: 0.32, 4.20). Conclusion: The concept of functional vitamin D deficiency, reflecting calcium metabolic stress, should be considered in studies of vitamin D in pregnancy. The SCOPE pregnancy cohort is registered at http://www.anzctr.org.au as ACTRN12607000551493.
Description
Keywords
Vitamin D , 25-hydroxyvitamin D , Parathyroid hormone , Pregnancy , Perinatal , Mean arterial pressure , Gestational hypertension , Preeclampsia , Small-for-gestational-age
Citation
Hemmingway, A., Kenny, L. C., Malvisi, L. and Kiely, M. E. (2018) 'Exploring the concept of functional vitamin D deficiency in pregnancy: impact of the interaction between 25-hydroxyvitamin D and parathyroid hormone on perinatal outcomes', The American Journal of Clinical Nutrition, 108(4), pp. 821-829. doi: 10.1093/ajcn/nqy150
Link to publisher’s version
Copyright
© 2018 American Society for Nutrition. Published by Oxford University Press. This is a pre-copyedited, author-produced version of an article accepted for publication in American Journal of Clinical Nutrition following peer review. The version of record, 108, Issue 4, 1 October 2018, Pages 821–829, is available online at: https://doi.org/10.1093/ajcn/nqy150