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Calcium supplements and bone resorption in pregnancy: a randomized crossover trial.

Authors
Janakiraman V; Ettinger A; Mercado-Gacia A; Hu H; Hernandez-Avila M
Source
Am J Prev Med 2003 Mar; 24(3):260-264
NIOSHTIC No.
20057024
Abstract
Background: Pregnancy is a time of increased need for calcium. The role of calcium supplements in altering maternal responses to fetal demand for calcium is not fully understood. This article describes the results of a randomized, crossover trial of calcium supplementation on bone resorption among pregnant women. Design Setting/Participants: Thirty-one Mexican women at 25-35 weeks gestation participated in the study for 20 days. Each woman received a 1200 mg calcium supplement on 10 consecutive days and a multivitamin without calcium for 10 days. Urine samples were collected daily. Two pooled specimens from each subject (representing urine from multivitamin days and from calcium days) were preserved, and levels of cross-linked, N-telopeptides of type I collagen (NTX), a biomarker of bone resorption, were measured. Dietary calcium intake was assessed using a food-frequency questionnaire. Results: Of the 31 participants, 27 (87.1%) showed reductions in urinary NTX levels while ingesting calcium supplements. When not ingesting calcium, NTX levels for the 31 subjects had a mean of 96.8 nM BCE/mM creatinine; this was significantly higher (p 0.001) than the mean urinary NTX levels of 83.2 nM BCE/mM creatinine during ingestion of the calcium supplements. Neither age nor dietary calcium intake was a significant predictor of treatment effect. Conclusion: A bedtime, 1200-mg calcium supplement during the third trimester of pregnancy reduces maternal bone resorption by an average of 13.6 nM BCE/mM creatinine (14%), as reflected by urinary NTX levels. These results suggest that calcium supplements reduce maternal skeletal-bone turnover during the third trimester of pregnancy.
Keywords
Calcium; Bone structure; Humans; Women; Pregnancy; Urinalysis; Urine; Sampling; Biomarkers; Questionnaires; Statistical analysis
Contact
Vanitha Janakiraman, MD, Department of Ob-Gyn, Brigham and Women's Hospital, 75 Francis St., Boston MA 02115
CODEN
AJPMEA
CAS No.
7440-70-2
Publication Date
20030301
Document Type
Journal Article
Email Address
vjanakiraman@partners.org
Funding Type
Grant
Fiscal Year
2003
Identifying No.
Grant-Number-T42-CCT-122961
Issue of Publication
3
ISSN
0749-3797
Source Name
American Journal of Preventive Medicine
State
MA
Performing Organization
Harvard School of Public Health
Page last reviewed: May 11, 2023
Content source: National Institute for Occupational Safety and Health Education and Information Division