Vitamin D during pregnancy: why observational studies suggest deficiency and interventional studies show no improvement in clinical outcomes? A narrative review.
J Endocrinol Invest
; 38(12): 1265-75, 2015 Dec.
Article
en En
| MEDLINE
| ID: mdl-26219612
ABSTRACT
A considerable number of studies have examined vitamin D status during pregnancy. Although data from observational studies denote vitamin D hypovitaminosis (deficiency or insufficiency) during pregnancy is associated with a plethora of adverse maternal and neonatal outcomes, data from interventional (supplementation) trials fail to reveal a significant impact on maternal and offspring health. The aim of this narrative review was to critically appraise the methodology of the most representative published randomized controlled trials in an attempt to explain the difference between observational and supplementation results. We found that this difference could be attributed to a variety of factors, namely (i) study design (lack of a specific outcome in conjunction with timing of supplementation, enrolment of participants with heterogeneous vitamin D status); (ii) pitfalls in the interpretation of vitamin D equilibrium (lack of determination of plasma half-life); (iii) supplementation regimen (administration of a wide range of regimens, in terms of dose, bolus and form); (iv) geographical characteristics (vitamin D needs could vary significantly within a country, particularly in areas with a wide range of latitude gradient); (v) adaptations of vitamin D metabolism during pregnancy (vitamin D and calcium equilibrium are changed during pregnancy compared with the non-pregnant state) and (vi) supplementation of populations with low baseline 25(OH)D values would likely manifest beneficial effects. All these parameters should be taken into consideration in the design of future vitamin D supplementation trials.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Complicaciones del Embarazo
/
Vitamina D
/
Deficiencia de Vitamina D
/
Ensayos Clínicos Controlados Aleatorios como Asunto
/
Evaluación de Resultado en la Atención de Salud
/
Estudios Observacionales como Asunto
Tipo de estudio:
Clinical_trials
/
Observational_studies
Límite:
Female
/
Humans
/
Pregnancy
Idioma:
En
Revista:
J Endocrinol Invest
Año:
2015
Tipo del documento:
Article
País de afiliación:
Grecia