Effect of calcium supplementation on bone resorption in pregnancy and the early postpartum: a randomized controlled trial in Mexican WomenReportar como inadecuado

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Nutrition Journal

, 13:116

First Online: 16 December 2014Received: 09 August 2014Accepted: 11 December 2014


BackgroundCalcium needs are physiologically upregulated during pregnancy and lactation to meet demands of the developing fetus and breastfeeding infant. Maternal calcium homeostasis is maintained by hormonal adaptive mechanisms, thus, the role of dietary calcium supplementation in altering maternal responses to fetal-infant demand for calcium is thought to be limited. However, increased calcium absorption is directly related to maternal calcium intake and dietary supplementation has been suggested to prevent transient bone loss associated with childbearing.

MethodsIn a double-blind, randomized placebo-controlled trial, we randomly assigned 670 women in their first trimester of pregnancy to 1,200 mg-day calcium N = 334 or placebo N = 336. Subjects were followed through 1-month postpartum and the effect on urinary cross-linked N-telopeptides NTx of type I collagen, a specific marker of bone resorption, was evaluated using an intent-to-treat analysis. Women with a baseline and at least one follow-up measurement N = 563; 84% were included. Subsequent analyses were conducted stratifying subjects by compliance assessed using pill counts. In random subsets of participants, bone-specific alkaline phosphatase BAP N = 100 and quantitative ultrasound QUS N = 290 were also measured.

ResultsCalcium was associated with an overall reduction of 15.8% in urinary NTx relative to placebo p < 0.001. Among those who consumed ≥50%, ≥67%, and ≥75% of pills, respectively, the effect was associated with 17.3%, 21.3%, and 22.1% reductions in bone resorption all p < 0.001. There was no significant effect of calcium on bone formation measured by BAP. However, by 1-month postpartum, those in the calcium group had significantly lower NTx-BAP ratios than those in the placebo group p = 0.04 indicating a net reduction in bone loss in the supplement group by the end of follow-up. Among subjects who consumed ≥50% and ≥75% of pills, respectively, calcium was also associated with an increase of 26.3 m-s p = 0.03 and 59.0 m-s p = 0.009 in radial SOS relative to placebo by 1-month postpartum.

ConclusionsCalcium administered during pregnancy and the early postpartum period, to women with intakes around adequacy, was associated with reduced bone resorption and, thus, may constitute a practical intervention to prevent transient skeletal loss associated with childbearing.

Trial registrationClinicalTrials.gov Identifier NCT00558623

KeywordsBone-specific alkaline phosphatase Calcium Clinical trials Lactation Pregnancy Quantitative ultrasound bone speed of sound Urinary N-telopeptide of type I collagen AbbreviationsBCEBone collagen equivalents

BAPBone-specific alkaline phosphatase

BMDBone mineral density

DXADual-energy x-ray absorptiometry

QUSQuantitative ultrasound

SOSSpeed of sound

NTxUrinary cross-linked N-telopeptides of type I collagen.

Electronic supplementary materialThe online version of this article doi:10.1186-1475-2891-13-116 contains supplementary material, which is available to authorized users.

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Autor: Adrienne S Ettinger - Héctor Lamadrid-Figueroa - Adriana Mercado-García - Katarzyna Kordas - Richard J Wood - Karen E P

Fuente: https://link.springer.com/


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