Changes in plasma concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D during pregnancy: a Brazilian cohort

Amanda C.Cunha Figueiredo, Paula Guedes Cocate, Amanda R.Amorim Adegboye, Ana Beatriz Franco-Sena, Dayana R. Farias, Maria Beatriz Trindade de Castro, Alex Brito, Lindsay H. Allen, Rana R. Mokhtar, Michael F. Holick, Gilberto Kac

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

Purpose: To characterize the physiological changes in 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)2D] throughout pregnancy. Methods: Prospective cohort of 229 apparently healthy pregnant women followed at 5th–13th, 20th–26th, and 30th–36th gestational weeks. 25(OH)D and 1,25(OH)2D concentrations were measured by LC–MS/MS. Statistical analyses included longitudinal linear mixed-effects models adjusted for parity, season, education, self-reported skin color, and pre-pregnancy BMI. Vitamin D status was defined based on 25(OH)D concentrations according to the Endocrine Society Practice Guideline and Institute of Medicine (IOM) for adults. Results: The prevalence of 25(OH)D <75 nmol/L was 70.4, 41.0, and 33.9%; the prevalence of 25(OH)D <50 nmol/L was 16.1, 11.2, and 10.2%; and the prevalence of 25(OH)D <30 nmol/L was 2, 0, and 0.6%, at the first, second, and third trimesters, respectively. Unadjusted analysis showed an increase in 25(OH)D (β = 0.869; 95% CI 0.723–1.014; P < 0.001) and 1,25(OH)2D (β = 3.878; 95% CI 3.136–4.620; P < 0.001) throughout pregnancy. Multiple adjusted analyses showed that women who started the study in winter (P < 0.001), spring (P < 0.001), or autumn (P = 0.028) presented a longitudinal increase in 25(OH)D concentrations, while women that started during summer did not. Increase of 1,25(OH)2D concentrations over time in women with insufficient vitamin D (50–75 nmol/L) at baseline was higher compared to women with sufficient vitamin D (≥75 nmol/L) (P = 0.006). Conclusions: The prevalence of vitamin D inadequacy varied significantly according to the adopted criteria. There was a seasonal variation of 25(OH)D during pregnancy. The women with insufficient vitamin D status present greater longitudinal increases in the concentrations of 1,25(OH)2D in comparison to women with sufficiency.

Original languageEnglish
Pages (from-to)1059-1072
Number of pages14
Journaleuropean journal of nutrition
Volume57
DOIs
Publication statusPublished - 28 Mar 2018
Externally publishedYes

Keywords

  • Cohort
  • Micronutrients
  • Pregnancy
  • Seasons
  • Tropical country
  • Vitamin D

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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