Nutritional Epidemiology Observatory, Josué de Castro Nutrition Institute, Rio de Janeiro Federal University, Avenida Carlos Chagas Filho, 373, CCS, Bloco J, 2° andar, Cidade Universitária-Ilha do Fundão, Rio de Janeiro, 21941-902, Brazil.
Division of Nutrition, Food and Public Health, Department of Life Science, University of Westminster, London, UK.
Eur J Nutr. 2018 Apr;57(3):1059-1072. doi: 10.1007/s00394-017-1389-z. Epub 2017 Mar 28.
To characterize the physiological changes in 25-hydroxyvitamin D [25(OH)D] and 1,25-dihydroxyvitamin D [1,25(OH)D] throughout pregnancy.
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)D 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.
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)D (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)D 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).
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)D in comparison to women with sufficiency.
描述 25-羟维生素 D [25(OH)D]和 1,25-二羟维生素 D [1,25(OH)D]在整个孕期的生理变化。
对 229 名明显健康的孕妇进行前瞻性队列研究，在第 5-13 周、20-26 周和 30-36 周时进行随访。采用 LC-MS/MS 测定 25(OH)D 和 1,25(OH)D 浓度。统计分析包括调整了产次、季节、教育程度、自我报告肤色和孕前 BMI 的纵向线性混合效应模型。根据内分泌学会实践指南和医学研究所（IOM）的标准，将维生素 D 状态定义为基于 25(OH)D 浓度。
第 1、2 和 3 孕期时，25(OH)D<75nmol/L 的发生率分别为 70.4%、41.0%和 33.9%；25(OH)D<50nmol/L 的发生率分别为 16.1%、11.2%和 10.2%；25(OH)D<30nmol/L 的发生率分别为 2.0%、0.0%和 0.6%。未经调整的分析显示，25(OH)D（β=0.869；95%CI 0.723-1.014；P<0.001）和 1,25(OH)D（β=3.878；95%CI 3.136-4.620；P<0.001）在整个孕期均呈上升趋势。多因素分析显示，在冬季（P<0.001）、春季（P<0.001）或秋季（P=0.028）开始研究的女性 25(OH)D 浓度呈纵向升高，而在夏季开始研究的女性则没有。与维生素 D 充足（≥75nmol/L）的女性相比，基线时维生素 D 不足（50-75nmol/L）的女性 1,25(OH)D 浓度随时间的纵向升高更高（P=0.006）。
根据采用的标准，维生素 D 不足的发生率差异显著。孕期 25(OH)D 存在季节性变化。与维生素 D 充足的女性相比，维生素 D 状态不足的女性 1,25(OH)D 浓度的纵向升高更大。
