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Weaver CM. Next-generation health benefits of maternal calcium supplementation. Am J Clin Nutr 2024; 119:1377-1378. [PMID: 38839191 DOI: 10.1016/j.ajcnut.2024.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 06/07/2024] Open
Affiliation(s)
- Connie M Weaver
- School of Exercise Physiology and Nutritional Sciences, College of Health and Human Services, San Diego State University, San Diego, CA, United States.
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Prentice A, Jarjou LM, Goldberg GR, Schoenbuchner SM, Moore SE, Ward KA, Cole TJ. Effects of maternal calcium supplementation on offspring blood pressure and growth in childhood and adolescence in a population with a low-calcium intake: follow-up study of a randomized controlled trial. Am J Clin Nutr 2024; 119:1443-1454. [PMID: 38839195 PMCID: PMC11196864 DOI: 10.1016/j.ajcnut.2024.02.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 02/13/2024] [Accepted: 02/18/2024] [Indexed: 06/07/2024] Open
Abstract
BACKGROUND The World Health Organization recommends calcium supplementation (1500-2000 mg/d) during pregnancy for women with a low-calcium intake. OBJECTIVES The purpose of this study was to investigate whether pregnancy calcium supplementation affects offspring blood pressure and growth in The Gambia where calcium intakes are low (300-400 mg/d). METHODS Follow-up of offspring born during a randomized controlled trial of pregnancy calcium supplementation (ISRCTN96502494, 1996-2000) in which mothers were randomly assigned to 1500 mg Ca/d (Ca) or placebo (P) from 20 wk pregnancy to delivery. Offspring were enrolled at age 3 y in studies where blood pressure and anthropometry were measured under standardized conditions at approximately 2-yearly intervals. Mean blood pressure and growth curves were fitted for females and males separately, using the longitudinal SuperImposition by Translation and Rotation (SITAR) mixed effects model. This generates 3 individual-specific random effects: size, timing, and intensity, reflecting differences in size, age at peak velocity, and peak velocity through puberty relative to the mean curve, respectively. RESULTS Five hundred twenty-three singleton infants were born during the trial (maternal group assignment: Ca/P = 259/264). Four hundred ninety-one were enrolled as children (females: F-Ca/F-P = 122/129 and males: M-Ca/M-P = 119/121) and measured regularly from 3.0 y to mean age 18.4 y; 90% were measured on ≥8 occasions. SITAR revealed differences in the systolic blood pressure and height curves between pregnancy supplement groups in females, but not in males. F-Ca had lower systolic blood pressure than F-P at all ages (size = -2.1 ± SE 0.8 mmHg; P = 0.005) and lower peak height velocity (intensity = -2.9 ± SE 1.1%, P = 0.009). No significant pregnancy supplement effects were seen for other measures. CONCLUSIONS This study showed, in female offspring, that pregnancy calcium supplementation may lower systolic blood pressure and slow linear growth in childhood and adolescence, adding to evidence of offspring sexual dimorphism in responses to maternal supplementation. Further research is warranted on the long-term and intergenerational effects of antenatal supplementations. This trial was registered at ISRCTN Registry as ISRCTN96502494.
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Affiliation(s)
- Ann Prentice
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Serrekunda, The Gambia; MRC Nutrition and Bone Health Research Group, Cambridge, United Kingdom; MRC Epidemiology Unit, University of Cambridge, Cambridge, United Kingdom.
| | - Landing Ma Jarjou
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Serrekunda, The Gambia
| | - Gail R Goldberg
- MRC Nutrition and Bone Health Research Group, Cambridge, United Kingdom
| | - Simon M Schoenbuchner
- MRC Nutrition and Bone Health Research Group, Cambridge, United Kingdom; Centre for Trials Research, Cardiff University, Cardiff, United Kingdom
| | - Sophie E Moore
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Serrekunda, The Gambia; Department of Women and Children's Health, Kings College London, London, United Kingdom
| | - Kate A Ward
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Serrekunda, The Gambia; MRC Lifecourse Epidemiology Centre, University of Southampton, Southampton, United Kingdom
| | - Tim J Cole
- Department of Population, Policy and Practice Research and Teaching, University College London Great Ormond Street Institute of Child Health, London, United Kingdom
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Rocha T, Allotey J, Palacios A, Vogel JP, Smits L, Carroli G, Mistry H, Young T, Qureshi ZP, Cormick G, Snell KIE, Abalos E, Pena-Rosas JP, Khan KS, Larbi KK, Thorson A, Singata-Madliki M, Hofmeyr GJ, Bohren M, Riley R, Betran AP, Thangaratinam S. Calcium supplementation to prevent pre-eclampsia: protocol for an individual participant data meta-analysis, network meta-analysis and health economic evaluation. BMJ Open 2023; 13:e065538. [PMID: 37169508 PMCID: PMC10186423 DOI: 10.1136/bmjopen-2022-065538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 04/11/2023] [Indexed: 05/13/2023] Open
Abstract
INTRODUCTION Low dietary calcium intake is a risk factor for pre-eclampsia, a major contributor to maternal and perinatal mortality and morbidity worldwide. Calcium supplementation can prevent pre-eclampsia in women with low dietary calcium. However, the optimal dose and timing of calcium supplementation are not known. We plan to undertake an individual participant data (IPD) meta-analysis of randomised trials to determine the effects of various calcium supplementation regimens in preventing pre-eclampsia and its complications and rank these by effectiveness. We also aim to evaluate the cost-effectiveness of calcium supplementation to prevent pre-eclampsia. METHODS AND ANALYSIS We will identify randomised trials on calcium supplementation before and during pregnancy by searching major electronic databases including Embase, CINAHL, MEDLINE, CENTRAL, PubMed, Scopus, AMED, LILACS, POPLINE, AIM, IMSEAR, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform, without language restrictions, from inception to February 2022. Primary researchers of the identified trials will be invited to join the International Calcium in Pregnancy Collaborative Network and share their IPD. We will check each study's IPD for consistency with the original authors before standardising and harmonising the data. We will perform a series of one-stage and two-stage IPD random-effect meta-analyses to obtain the summary intervention effects on pre-eclampsia with 95% CIs and summary treatment-covariate interactions (maternal risk status, dietary intake, timing of intervention, daily dose of calcium prescribed and total intake of calcium). Heterogeneity will be summarised using tau2, I2 and 95% prediction intervals for effect in a new study. Sensitivity analysis to explore robustness of statistical and clinical assumptions will be carried out. Minor study effects (potential publication bias) will be investigated using funnel plots. A decision analytical model for use in low-income and middle-income countries will assess the cost-effectiveness of calcium supplementation to prevent pre-eclampsia. ETHICS AND DISSEMINATION No ethical approvals are required. We will store the data in a secure repository in an anonymised format. The results will be published in peer-reviewed journals. PROSPERO REGISTRATION NUMBER CRD42021231276.
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Affiliation(s)
- Thaís Rocha
- WHO Collaborating Centre for Global Women's Health, Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - John Allotey
- WHO Collaborating Centre for Global Women's Health, Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Alfredo Palacios
- Health Economics, Institute for Clinical Effectiveness and Health Policy, Buenos Aires, Argentina
| | - Joshua Peter Vogel
- Maternal, Child and Adolescent Health Program, Burnet Institute, Melbourne, Victoria, Australia
| | - Luc Smits
- Department of Epidemiology, Care and Public Health Research Institute, Maastricht University, Maastricht, The Netherlands
| | | | - Hema Mistry
- Warwick Evidence, University of Warwick, Coventry, UK
| | - Taryn Young
- Centre for Evidence-Based Health Care, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
- South African Cochrane Centre, South African Medical Research Council, Cape Town, South Africa
| | - Zahida P Qureshi
- Department of Obstetrics and Gynecology, University of Nairobi, Nairobi, Kenya
| | - Gabriela Cormick
- Department of Health Technology Assessment and Health Economics, Institute for Clinical Effectiveness and Health Policy, Buenos Aires, Argentina
| | - Kym I E Snell
- Centre for Prognosis Research, School of Medicine, Keele University, Keele, UK
| | - Edgardo Abalos
- Centro Rosarino de Estudios Perinatales (CREP), Rosario, Argentina
| | | | - Khalid Saeed Khan
- Public Health, University of Granada Faculty of Medicine, Granada, Spain
| | | | - Anna Thorson
- Reproductive Health and Research, World Health Organization, Geneva, Switzerland
| | - Mandisa Singata-Madliki
- Effective Care Research Unit (ECRU), East London Hospital Complex, East London, South Africa
| | | | - Meghan Bohren
- Centre for Health Equity, University of Melbourne School of Population and Global Health, Carlton, Victoria, Australia
| | - Richard Riley
- Centre for Prognosis Research, School of Medicine, Keele University, Keele, UK
| | - Ana Pilar Betran
- Reproductive Health and Research, World Health Organization, Geneva, Switzerland
| | - Shakila Thangaratinam
- WHO Collaborating Centre for Global Women's Health, Institute of Metabolism and Systems Research, University of Birmingham College of Medical and Dental Sciences, Birmingham, UK
- Birmingham Women's and Children's Hospitals NHS Foundation Trust, Birmingham, UK
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Hassan MG, Chen C, Ismail HA, Zaher AR, Cox TC, Goodwin AF, Jheon AH. Altering calcium and phosphorus supplementation in pregnancy and lactation affects offspring craniofacial morphology in a sex-specific pattern. Am J Orthod Dentofacial Orthop 2022; 161:e446-e455. [DOI: 10.1016/j.ajodo.2021.12.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/01/2021] [Accepted: 12/01/2021] [Indexed: 11/01/2022]
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Korhonen P, Tihtonen K, Isojärvi J, Ojala R, Ashorn U, Ashorn P, Tammela O. Calcium supplementation during pregnancy and long‐term offspring outcome: a systematic literature review and meta‐analysis. Ann N Y Acad Sci 2022; 1510:36-51. [PMID: 34978718 PMCID: PMC9304138 DOI: 10.1111/nyas.14729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/04/2021] [Accepted: 11/04/2021] [Indexed: 11/29/2022]
Abstract
The World Health Organization currently recommends calcium supplementation for pregnant women, especially those with low calcium intakes, to reduce the risk of hypertension and preeclampsia. We aimed to evaluate the effect of this intervention on selected offspring outcomes. A systematic search was conducted in 11 databases for published randomized controlled trials (RCTs) on the effect of maternal calcium supplementation with or without vitamin D during pregnancy on selected offspring cardiovascular, growth, and metabolic and neurodevelopmental outcomes. Screening of titles and abstracts of 3555 records and full texts of 31 records yielded six RCTs (nine reports, n = 1616). Forest plot analyses were performed if at least two studies presented comparable data on the same outcome. In one study (n = 591), high‐dose calcium supplementation during pregnancy was associated with a decreased risk of offspring high systolic blood pressure at 5–7 years of age (risk ratio = 0.59; 95% confidence interval: 0.39–0.90). The effects of the intervention on offspring growth, metabolic, and neurodevelopmental outcomes remain unknown because of conflicting or insufficient data. High risk of attrition bias decreased the quality of the evidence. Limited available data from RCTs do not provide sufficient evidence to conclude that prenatal calcium supplementation influences offspring health outcomes beyond the newborn period.
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Affiliation(s)
- Päivi Korhonen
- Department of Pediatrics Tampere University Hospital Tampere Finland
- Faculty of Medicine and Health Technology, Center for Child, Adolescent, and Maternal Health Research Tampere University Tampere Finland
| | - Kati Tihtonen
- Faculty of Medicine and Health Technology, Center for Child, Adolescent, and Maternal Health Research Tampere University Tampere Finland
- Department of Obstetrics and Gynecology Tampere University Hospital Tampere Finland
| | | | - Riitta Ojala
- Department of Pediatrics Tampere University Hospital Tampere Finland
- Faculty of Medicine and Health Technology, Center for Child, Adolescent, and Maternal Health Research Tampere University Tampere Finland
| | - Ulla Ashorn
- Faculty of Medicine and Health Technology, Center for Child, Adolescent, and Maternal Health Research Tampere University Tampere Finland
| | - Per Ashorn
- Department of Pediatrics Tampere University Hospital Tampere Finland
- Faculty of Medicine and Health Technology, Center for Child, Adolescent, and Maternal Health Research Tampere University Tampere Finland
| | - Outi Tammela
- Department of Pediatrics Tampere University Hospital Tampere Finland
- Faculty of Medicine and Health Technology, Center for Child, Adolescent, and Maternal Health Research Tampere University Tampere Finland
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Tihtonen K, Korhonen P, Isojärvi J, Ojala R, Ashorn U, Ashorn P, Tammela O. Calcium supplementation during pregnancy and maternal and offspring bone health: a systematic review and meta-analysis. Ann N Y Acad Sci 2021; 1509:23-36. [PMID: 34780069 PMCID: PMC9298950 DOI: 10.1111/nyas.14705] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 09/26/2021] [Indexed: 11/29/2022]
Abstract
Insufficient calcium intake during pregnancy may lead to maternal bone resorption and lower bone density of offspring. We evaluated the impact of supplementary calcium with or without vitamin D during pregnancy on maternal and offspring bone mineral density (BMD) and teeth firmness of the offspring. Randomized controlled trials (RCTs) were searched systematically in 11 databases. Two researchers independently screened the titles and abstracts of 3555 records and the full texts of 31 records to examine eligibility. The search yielded seven RCTs (11 reports, n = 1566). No advantage of calcium supplementation was found on maternal BMD after delivery or during breastfeeding, or on offspring BMD, even when dietary calcium intake was low. The results were neither modified by the dose of calcium nor concomitant vitamin D administration. A suspicion of some long‐term harm of the intervention on maternal BMD and growth of female offspring was raised based on the data. One study suggested some benefit of high‐dose calcium supplementation on offspring teeth firmness at 12 years old. A low number of the studies and abundant missing data reduced the quality of the findings. The impact of calcium supplementation on maternal and offspring bone health was deemed unknown because of inconclusive research results.
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Affiliation(s)
- Kati Tihtonen
- Department of Obstetrics and Gynecology, Tampere University Hospital, Tampere, Finland.,Faculty of Medicine and Health Technology, Center for Child, Adolescent, and Maternal Health Research, Tampere University, Tampere, Finland
| | - Päivi Korhonen
- Faculty of Medicine and Health Technology, Center for Child, Adolescent, and Maternal Health Research, Tampere University, Tampere, Finland.,Department of Pediatrics, Tampere University Hospital, Tampere, Finland
| | | | - Riitta Ojala
- Faculty of Medicine and Health Technology, Center for Child, Adolescent, and Maternal Health Research, Tampere University, Tampere, Finland.,Department of Pediatrics, Tampere University Hospital, Tampere, Finland
| | - Ulla Ashorn
- Faculty of Medicine and Health Technology, Center for Child, Adolescent, and Maternal Health Research, Tampere University, Tampere, Finland
| | - Per Ashorn
- Faculty of Medicine and Health Technology, Center for Child, Adolescent, and Maternal Health Research, Tampere University, Tampere, Finland.,Department of Pediatrics, Tampere University Hospital, Tampere, Finland
| | - Outi Tammela
- Faculty of Medicine and Health Technology, Center for Child, Adolescent, and Maternal Health Research, Tampere University, Tampere, Finland.,Department of Pediatrics, Tampere University Hospital, Tampere, Finland
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Keats EC, Oh C, Chau T, Khalifa DS, Imdad A, Bhutta ZA. Effects of vitamin and mineral supplementation during pregnancy on maternal, birth, child health and development outcomes in low- and middle-income countries: A systematic review. CAMPBELL SYSTEMATIC REVIEWS 2021; 17:e1127. [PMID: 37051178 PMCID: PMC8356361 DOI: 10.1002/cl2.1127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Background Almost two billion people who are deficient in vitamins and minerals are women and children in low- and middle-income countries (LMIC). These deficiencies are worsened during pregnancy due to increased energy and nutritional demands, causing adverse outcomes in mother and child. To reduce micronutrient deficiencies, several strategies have been implemented, including diet diversification, large-scale and targeted fortification, staple crop bio-fortification and micronutrient supplementation. Objectives To evaluate and summarize the available evidence on the effects of micronutrient supplementation during pregnancy in LMIC on maternal, fetal, child health and child development outcomes. This review will assess the impact of single micronutrient supplementation (calcium, vitamin A, iron, vitamin D, iodine, zinc, vitamin B12), iron-folic acid (IFA) supplementation, multiple micronutrient (MMN) supplementation, and lipid-based nutrient supplementation (LNS) during pregnancy. Search Methods We searched papers published from 1995 to 31 October 2019 (related programmes and good quality studies pre-1995 were limited) in CAB Abstracts, CINAHL, Cochrane Central Register of Controlled Trials, Embase, International Initiative for Impact Evaluations, LILACS, Medline, POPLINE, Web of Science, WHOLIS, ProQuest Dissertations & Theses Global, R4D, WHO International Clinical Trials Registry Platform. Non-indexed grey literature searches were conducted using Google, Google Scholar, and web pages of key international nutrition agencies. Selection Criteria We included randomized controlled trials (individual and cluster-randomized) and quasi-experimental studies that evaluated micronutrient supplementation in healthy, pregnant women of any age and parity living in a LMIC. LMIC were defined by the World Bank Group at the time of the search for this review. While the aim was to include healthy pregnant women, it is likely that these populations had one or more micronutrient deficiencies at baseline; women were not excluded on this basis. Data Collection and Analysis Two authors independently assessed studies for inclusion and risk of bias, and conducted data extraction. Data were matched to check for accuracy. Quality of evidence was assessed using the GRADE approach. Main Results A total of 314 papers across 72 studies (451,723 women) were eligible for inclusion, of which 64 studies (439,649 women) contributed to meta-analyses. Seven studies assessed iron-folic acid (IFA) supplementation versus folic acid; 34 studies assessed MMN vs. IFA; 4 studies assessed LNS vs. MMN; 13 evaluated iron; 13 assessed zinc; 9 evaluated vitamin A; 11 assessed vitamin D; and 6 assessed calcium. Several studies were eligible for inclusion in multiple types of supplementation. IFA compared to folic acid showed a large and significant (48%) reduction in the risk of maternal anaemia (average risk ratio (RR) 0.52, 95% CI 0.41 to 0.66; studies = 5; participants = 15,540; moderate-quality evidence). As well, IFA supplementation demonstrated a smaller but significant, 12% reduction in risk of low birthweight (LBW) babies (average RR 0.88, 95% CI 0.78 to 0.99; studies = 4; participants = 17,257; high-quality evidence). MMN supplementation was defined as any supplement that contained at least 3 micronutrients. Post-hoc analyses were conducted, where possible, comparing the differences in effect of MMN with 4+ components and MMN with 3 or 4 components. When compared to iron with or without FA, MMN supplementation reduced the risk of LBW by 15% (average RR 0.85, 95% CI 0.77 to 0.93; studies = 28; participants = 79,972); this effect was greater in MMN with >4 micronutrients (average RR 0.79, 95% CI 0.71 to 0.88; studies = 19; participants = 68,138 versus average RR 1.01, 95% CI 0.92 to 1.11; studies = 9; participants = 11,834). There was a small and significant reduction in the risk of stillbirths (average RR 0.91; 95% CI 0.86 to 0.98; studies = 22; participants = 96,772) and a small and significant effect on the risk of small-for-gestational age (SGA) (average RR 0.93; 95% CI 0.88 to 0.98; studies = 19; participants = 52,965). For stillbirths and SGA, the effects were greater among those provided MMN with 4+ micronutrients. Children whose mothers had been supplemented with MMN, compared to IFA, demonstrated a 16% reduced risk of diarrhea (average RR 0.84; 95% CI 0.76 to 0.92; studies = 4; participants = 3,142). LNS supplementation, compared to MMN, made no difference to any outcome; however, the evidence is limited. Iron supplementation, when compared to no iron or placebo, showed a large and significant effect on maternal anaemia, a reduction of 47% (average RR 0.53, 95% CI 0.43 to 0.65; studies = 6; participants = 15,737; moderate-quality evidence) and a small and significant effect on LBW (average RR 0.88, 95% CI 0.78 to 0.99; studies = 4; participants = 17,257; high-quality evidence). Zinc and vitamin A supplementation, each both compared to placebo, had no impact on any outcome examined with the exception of potentially improving serum/plasma zinc (mean difference (MD) 0.43 umol/L; 95% CI -0.04 to 0.89; studies = 5; participants = 1,202) and serum/plasma retinol (MD 0.13 umol/L; 95% CI -0.03 to 0.30; studies = 6; participants = 1,654), respectively. When compared to placebo, vitamin D supplementation may have reduced the risk of preterm births (average RR 0.64; 95% CI 0.40 to 1.04; studies = 7; participants = 1,262), though the upper CI just crosses the line of no effect. Similarly, calcium supplementation versus placebo may have improved rates of pre-eclampsia/eclampsia (average RR 0.45; 95% CI 0.19 to 1.06; studies = 4; participants = 9,616), though the upper CI just crosses 1. Authors' Conclusions The findings suggest that MMN and vitamin supplementation improve maternal and child health outcomes, including maternal anaemia, LBW, preterm birth, SGA, stillbirths, micronutrient deficiencies, and morbidities, including pre-eclampsia/eclampsia and diarrhea among children. MMN supplementation demonstrated a beneficial impact on the most number of outcomes. In addition, MMN with >4 micronutrients appeared to be more impactful than MMN with only 3 or 4 micronutrients included in the tablet. Very few studies conducted longitudinal analysis on longer-term health outcomes for the child, such as anthropometric measures and developmental outcomes; this may be an important area for future research. This review may provide some basis to guide continual discourse around replacing IFA supplementation with MMN along with the use of single micronutrient supplementation programs for specific outcomes.
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Affiliation(s)
- Emily C. Keats
- Centre for Global Child HealthThe Hospital for Sick ChildrenTorontoCanada
| | - Christina Oh
- Centre for Global Child HealthThe Hospital for Sick ChildrenTorontoCanada
| | - Tamara Chau
- Centre for Global Child HealthThe Hospital for Sick ChildrenTorontoCanada
| | - Dina S. Khalifa
- Centre for Global Child HealthThe Hospital for Sick ChildrenTorontoCanada
| | - Aamer Imdad
- PediatricsUpstate Medical University, SyracuseNew YorkUSA
| | - Zulfiqar A. Bhutta
- Centre for Global Child HealthThe Hospital for Sick ChildrenTorontoCanada
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Abstract
Policy decisions and the practice of public health nutrition need to be based on solid evidence, developed through rigorous research studies where objective measures are used and results that run counter to dogma are not dismissed but investigated. In recent years, enhancements in study designs, and methodologies for systematic reviews and meta-analysis, have improved the evidence-base for nutrition policy and practice. However, these still rely on a full appreciation of the strengths and limitations of the measures on which conclusions are drawn and on the thorough investigation of outcomes that do not fit expectations or prevailing convictions. The importance of ‘hard facts’ and ‘misfits’ in research designed to advance knowledge and improve public health nutrition is illustrated in this paper through a selection of studies from different stages in my research career, focused on the nutritional requirements of resource-poor populations in Africa and Asia.
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Abstract
For many people, micronutrient requirement means the amount needed in the diet to ensure adequacy. Dietary reference values (DRV) provide guidance on the daily intake of vitamins and minerals required to ensure the needs of the majority in the population are covered. These are developed on estimates of the quantity of each micronutrient required by the average person, the bioavailability of the micronutrient from a typical diet and the interindividual variability in these amounts. Sex differences are inherent in the requirements for many micronutrients because they are influenced by body size or macronutrient intake. These are reflected in different DRV for males and females for some micronutrients, but not all, either when data from males and females are combined or when there is no evidence of sex differences. Pregnancy and lactation represent times when micronutrient requirements for females may differ from males, and separate DRV are provided. For some micronutrients, no additional requirement is indicated during pregnancy and lactation because of physiological adaptations. To date, little account has been taken of more subtle sex differences in growth and maturation rates, health vulnerabilities and in utero and other programming effects. Over the years, the MRC Nutrition and Bone Health Group has contributed data on micronutrient requirements across the lifecourse, particularly for calcium and vitamin D, and shown that supplementation can have unexpected sex-specific consequences that require further investigation. The present paper outlines the current issues and the need for future research on sex differences in micronutrient requirements.
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Kinshella MLW, Omar S, Scherbinsky K, Vidler M, Magee LA, von Dadelszen P, Moore SE, Elango R. Effects of Maternal Nutritional Supplements and Dietary Interventions on Placental Complications: An Umbrella Review, Meta-Analysis and Evidence Map. Nutrients 2021; 13:472. [PMID: 33573262 PMCID: PMC7912620 DOI: 10.3390/nu13020472] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 01/26/2021] [Indexed: 01/08/2023] Open
Abstract
The placenta is a vital, multi-functional organ that acts as an interface between maternal and fetal circulation during pregnancy. Nutritional deficiencies during pregnancy alter placental development and function, leading to adverse pregnancy outcomes, such as pre-eclampsia, infants with small for gestational age and low birthweight, preterm birth, stillbirths and maternal mortality. Maternal nutritional supplementation may help to mitigate the risks, but the evidence base is difficult to navigate. The primary purpose of this umbrella review is to map the evidence on the effects of maternal nutritional supplements and dietary interventions on pregnancy outcomes related to placental disorders and maternal mortality. A systematic search was performed on seven electronic databases, the PROSPERO register and references lists of identified papers. The results were screened in a three-stage process based on title, abstract and full-text by two independent reviewers. Randomized controlled trial meta-analyses on the efficacy of maternal nutritional supplements or dietary interventions were included. There were 91 meta-analyses included, covering 23 types of supplements and three types of dietary interventions. We found evidence that supports supplementary vitamin D and/or calcium, omega-3, multiple micronutrients, lipid-based nutrients, and balanced protein energy in reducing the risks of adverse maternal and fetal health outcomes. However, these findings are limited by poor quality of evidence. Nutrient combinations show promise and support a paradigm shift to maternal dietary balance, rather than single micronutrient deficiencies, to improve maternal and fetal health. The review is registered at PROSPERO (CRD42020160887).
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Affiliation(s)
- Mai-Lei Woo Kinshella
- Department of Obstetrics and Gynaecology, BC Children’s and Women’s Hospital and University of British Columbia, Vancouver, BC V6Z 2K8, Canada; (M.-L.W.K.); (S.O.); (K.S.); (M.V.); (L.A.M.); (P.v.D.)
| | - Shazmeen Omar
- Department of Obstetrics and Gynaecology, BC Children’s and Women’s Hospital and University of British Columbia, Vancouver, BC V6Z 2K8, Canada; (M.-L.W.K.); (S.O.); (K.S.); (M.V.); (L.A.M.); (P.v.D.)
| | - Kerri Scherbinsky
- Department of Obstetrics and Gynaecology, BC Children’s and Women’s Hospital and University of British Columbia, Vancouver, BC V6Z 2K8, Canada; (M.-L.W.K.); (S.O.); (K.S.); (M.V.); (L.A.M.); (P.v.D.)
- Department of Pediatrics, University of British Columbia, Vancouver, BC V6H 0B3, Canada
| | - Marianne Vidler
- Department of Obstetrics and Gynaecology, BC Children’s and Women’s Hospital and University of British Columbia, Vancouver, BC V6Z 2K8, Canada; (M.-L.W.K.); (S.O.); (K.S.); (M.V.); (L.A.M.); (P.v.D.)
| | - Laura A. Magee
- Department of Obstetrics and Gynaecology, BC Children’s and Women’s Hospital and University of British Columbia, Vancouver, BC V6Z 2K8, Canada; (M.-L.W.K.); (S.O.); (K.S.); (M.V.); (L.A.M.); (P.v.D.)
- Department of Women & Children’s Health, King’s College London, London WC2R 2LS, UK;
| | - Peter von Dadelszen
- Department of Obstetrics and Gynaecology, BC Children’s and Women’s Hospital and University of British Columbia, Vancouver, BC V6Z 2K8, Canada; (M.-L.W.K.); (S.O.); (K.S.); (M.V.); (L.A.M.); (P.v.D.)
- Department of Women & Children’s Health, King’s College London, London WC2R 2LS, UK;
| | - Sophie E. Moore
- Department of Women & Children’s Health, King’s College London, London WC2R 2LS, UK;
- Medical Research Council Unit, The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, P.O. Box 273 Banjul, The Gambia
| | - Rajavel Elango
- Department of Pediatrics, University of British Columbia, Vancouver, BC V6H 0B3, Canada
- School of Population and Public Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Division of Neonatology, BC Women’s Hospital and Health Centre, Vancouver, BC V6H 3N1, Canada
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Liu D, Li S, Lei F, Zhao Y, Cheng Y, Dang S, Zeng L, Mi B, Qu P, Zhang B, Liu A, Li M, Shi G, Yan H. Associations between maternal calcium intake from diet and supplements during pregnancy and the risk of preterm birth in a Chinese population. Eur J Clin Nutr 2020; 75:141-150. [PMID: 32814854 DOI: 10.1038/s41430-020-00701-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 07/03/2020] [Accepted: 08/04/2020] [Indexed: 11/09/2022]
Abstract
BACKGROUND/OBJECTIVES Preterm birth is a global public health priority related to maternal nutrition. The effect of maternal calcium intake during pregnancy on preterm birth is inconclusive and data is lacking in China. We aimed to estimate the role of calcium intake from diet and supplements on preterm birth in the Chinese population. METHODS We used data of 7195 women from a large-scale cross-sectional study in Northwest China. Dietary intake was evaluated via a validated food frequency questionnaire, and other information was collected by a structured questionnaire. Generalized estimating equation models were used to estimate the relationship between calcium intake and preterm birth. RESULTS Inadequate dietary calcium intake was universal in our population (85.9%), and no association was found between daily dietary calcium intake and preterm birth. Maternal calcium supplementation was significantly associated with reduced risk of preterm birth (OR 0.72, 95% CI 0.60, 0.87, P = 0.001), particularly among women who commenced calcium supplementation in the second and third trimester of pregnancy with longer duration (OR 0.62, 95% CI 0.42, 0.91, P = 0.015). Higher daily calcium intake from supplements was linked with lower preterm birth risk (every 100 mg increase: OR 0.87, 95% CI 0.79, 0.96, P = 0.004). There is a negative association between daily total calcium intake and preterm birth among calcium supplement users (every 100 mg increase: OR 0.91, 95% CI 0.84, 0.97, P = 0.007). CONCLUSIONS In conclusion, appropriate calcium supplementation during pregnancy could be beneficial in the prevention of preterm birth, and it might be suitable for implementing in low calcium intake areas of China.
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Affiliation(s)
- Danmeng Liu
- Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Shanshan Li
- Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Fangliang Lei
- Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Yaling Zhao
- Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Yue Cheng
- Department of Nutrition, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Shaonong Dang
- Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Lingxia Zeng
- Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Baibing Mi
- Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Pengfei Qu
- Translational Medicine Center, Northwest Women's and Children's Hospital, No. 1616 Yanxiang Road, Xi'an, 710061, Shaanxi, China
| | - Binyan Zhang
- Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Amin Liu
- Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Minmin Li
- Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Guoshuai Shi
- Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Hong Yan
- Department of Epidemiology and Health Statistics, School of Public Health, Xi'an Jiaotong University Health Science Center, No. 76 Yanta West Road, Xi'an, 710061, Shaanxi, China. .,Nutrition and Food Safety Engineering Research Center of Shaanxi Province, Xi'an, 710061, Shaanxi, China. .,Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University, Ministry of Education, Xi'an, 710061, Shaanxi, China.
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12
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Sun X, Li H, He X, Li M, Yan P, Xun Y, Lu C, Yang K, Zhang X. The association between calcium supplement and preeclampsia and gestational hypertension: a systematic review and meta-analysis of randomized trials. Hypertens Pregnancy 2019; 38:129-139. [PMID: 30935246 DOI: 10.1080/10641955.2019.1593445] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVES The purpose of this study is to investigate whether calcium supplement with or without other drugs could reduce the risk of preeclampsia and gestational hypertension based on existed evidence, and to clarify whether there is discrepant effect among different population and using different dose. METHODS PubMed, Cochrane library, and EMBASE database were searched. Two authors independently screened all records and extracted data. The meta-analysis was performed to calculate risk ratios and 95% CIs using random-effects models. RESULTS 27 studies, with 28 492 pregnant women were included. The results showed calcium supplement was associated with lower incidence of preeclampsia (RR 0.51, 95% CI: 0.40 to 0.64) and gestational hypertension (RR 0.70, 95% CI: 0.60 to 0.82). Sub-analyses revealed high-dose (1.2-2 g/day), moderate-dose (0.6-1.2 g/day), and low-dose (<0.6 g/day) of calcium supplement could reduce the risk of preeclampsia. For gestational hypertension, only high dose and moderate dose groups were associated with reducing the risk of gestational hypertension. However, we could draw a conclusion which does group was the most protective, as we were unable to directly compare the effects of different doses. CONCLUSIONS This study indicated calcium supplementation might decrease the risk of preeclampsia and gestational hypertension. And results of subgroups analyses enhanced our confidence to the protective effect of calcium supplementation. However, further studies with direct comparison of different dose of calcium supplementation are needed to explore the ideal dose of calcium supplementation to prevent preeclampsia and gestational hypertension.
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Affiliation(s)
- Xiaotong Sun
- a Department of Obstetrics and Gynecology, The First Clinical Medical College , Lanzhou University, Gansu Provincial Hospital , Lanzhou , China
| | - Huijuan Li
- b School of Public Health , Lanzhou University , Lanzhou , China.,c Evidence-based Social Sciences Research Center , Lanzhou University , Lanzhou , China.,d Evidence-based Medicine Center, School of Basic Medical Sciences , Lanzhou University , Lanzhou , China
| | | | - Meixuan Li
- b School of Public Health , Lanzhou University , Lanzhou , China.,c Evidence-based Social Sciences Research Center , Lanzhou University , Lanzhou , China.,d Evidence-based Medicine Center, School of Basic Medical Sciences , Lanzhou University , Lanzhou , China
| | - Peijing Yan
- e Institute of Clinical Research and Evidence Based Medicine , Gansu Provincial Hospital , Lanzhou , China
| | - Yangqin Xun
- b School of Public Health , Lanzhou University , Lanzhou , China.,c Evidence-based Social Sciences Research Center , Lanzhou University , Lanzhou , China.,d Evidence-based Medicine Center, School of Basic Medical Sciences , Lanzhou University , Lanzhou , China
| | - Cuncun Lu
- c Evidence-based Social Sciences Research Center , Lanzhou University , Lanzhou , China.,d Evidence-based Medicine Center, School of Basic Medical Sciences , Lanzhou University , Lanzhou , China
| | - Kehu Yang
- b School of Public Health , Lanzhou University , Lanzhou , China.,c Evidence-based Social Sciences Research Center , Lanzhou University , Lanzhou , China.,d Evidence-based Medicine Center, School of Basic Medical Sciences , Lanzhou University , Lanzhou , China.,e Institute of Clinical Research and Evidence Based Medicine , Gansu Provincial Hospital , Lanzhou , China
| | - Xuehong Zhang
- f Reproductive Medicine Hospital of the First Hospital of Lanzhou University , Lanzhou , China
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Prentice A, Ward KA, Nigdikar S, Hawkesworth S, Moore SE. Pregnancy supplementation of Gambian mothers with calcium carbonate alters mid-childhood IGF1 in a sex-specific manner. Bone 2019; 120:314-320. [PMID: 30465917 DOI: 10.1016/j.bone.2018.11.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/02/2018] [Accepted: 11/17/2018] [Indexed: 01/01/2023]
Abstract
CONTEXT Sex-specific effects of pregnancy calcium carbonate supplementation have been reported in 8-12 year old Gambian children, indicating faster growth in boys but slower growth in girls born to calcium-supplemented mothers. OBJECTIVE To determine whether the pregnancy supplement resulted in sex-specific effects on offspring IGF1 and other growth-related indices in mid-childhood. DESIGN Analysis of archived data obtained in mid-childhood from the children of rural Gambian mothers who had been randomised to 1500 mgCa/d (Ca) or placebo (P) from 20 weeks pregnancy to delivery (ISRCTN96502494). PARTICIPANTS AND METHODS Of the 526 children born and followed in infancy, 290 had early-morning, fasting plasma assayed for IGF1, IGFBP3, leptin, insulin and calcium-related indices and had anthropometry performed at age 7.5 (SD1.2) years (N/group: Males(M)-Ca = 64, Females(F)-Ca = 77; M-P = 76, F-P = 73). Sex-specific effects of maternal supplementation were considered using regression with sexes separated and together to test for sex ∗ supplement interactions. RESULTS Boys had lower IGF1, IGFBP3, leptin and insulin than girls (P ≤ 0.004). IGF1 was higher in M-Ca than M-P (+14.2 (SE7.7)%, P = 0.05) but lower in F-Ca than F-P (-17.8 (SE7.4)%, P = 0.01); sex ∗ supplement interaction P = 0.001. IGF1 concentrations (ng/ml, geometric mean [-1SE,+1SE]) were M-Ca = 78.1[4.3,4.5], M-P = 67.8[3.4,3.6]; F-Ca = 99.5[4.8,5.1], F-P = 118.9[6.4,6.8]. Similar sex ∗ supplement interactions were seen for IGFBP3 and IGF1-adjusted-for-IGFBP3 but group differences were smaller. There were no significant supplement effects on the other biochemical indices. CONCLUSIONS Calcium carbonate supplementation of pregnant Gambian mothers resulted in higher IGF1 in boys and lower IGF1 in girls during mid-childhood, consistent with the reported maternal supplement effects on growth of the offspring in later childhood.
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Affiliation(s)
- Ann Prentice
- Medical Research Council Elsie Widdowson Laboratory, Cambridge CB1 9NL, United Kingdom; Medical Research Council Keneba, MRC Unit The Gambia at the London School of Hygiene and Tropical Medicine, P.O. Box 273, The Gambia.
| | - Kate A Ward
- Medical Research Council Elsie Widdowson Laboratory, Cambridge CB1 9NL, United Kingdom; Medical Research Council Lifecourse Epidemiology Unit, University of Southampton, Southampton SO16 6YD, United Kingdom
| | - Shailja Nigdikar
- Medical Research Council Elsie Widdowson Laboratory, Cambridge CB1 9NL, United Kingdom
| | - Sophie Hawkesworth
- Medical Research Council International Nutrition Group, London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Sophie E Moore
- Medical Research Council Keneba, MRC Unit The Gambia at the London School of Hygiene and Tropical Medicine, P.O. Box 273, The Gambia; Department of Women and Children's Health, King's College London, London SE1 7EH, United Kingdom
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Hofmeyr GJ, Lawrie TA, Atallah ÁN, Torloni MR. Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems. Cochrane Database Syst Rev 2018; 10:CD001059. [PMID: 30277579 PMCID: PMC6517256 DOI: 10.1002/14651858.cd001059.pub5] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Pre-eclampsia and eclampsia are common causes of serious morbidity and death. Calcium supplementation may reduce the risk of pre-eclampsia, and may help to prevent preterm birth. This is an update of a review last published in 2014. OBJECTIVES To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child outcomes. SEARCH METHODS We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (18 September 2017), and reference lists of retrieved studies. SELECTION CRITERIA We included randomised controlled trials (RCTs), including cluster-randomised trials, comparing high-dose calcium supplementation (at least 1 g daily of calcium) during pregnancy with placebo. For low-dose calcium we included quasi-randomised trials, trials without placebo, trials with cointerventions and dose comparison trials. DATA COLLECTION AND ANALYSIS Two researchers independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. Two researchers assessed the evidence using the GRADE approach. MAIN RESULTS We included 27 studies (18,064 women). We assessed the included studies as being at low risk of bias, although bias was frequently difficult to assess due to poor reporting and inadequate information on methods.High-dose calcium supplementation (≥ 1 g/day) versus placeboFourteen studies examined this comparison, however one study contributed no data. The 13 studies contributed data from 15,730 women to our meta-analyses. The average risk of high blood pressure (BP) was reduced with calcium supplementation compared with placebo (12 trials, 15,470 women: risk ratio (RR) 0.65, 95% confidence interval (CI) 0.53 to 0.81; I² = 74%). There was also a reduction in the risk of pre-eclampsia associated with calcium supplementation (13 trials, 15,730 women: average RR 0.45, 95% CI 0.31 to 0.65; I² = 70%; low-quality evidence). This effect was clear for women with low calcium diets (eight trials, 10,678 women: average RR 0.36, 95% CI 0.20 to 0.65; I² = 76%) but not those with adequate calcium diets. The effect appeared to be greater for women at higher risk of pre-eclampsia, though this may be due to small-study effects (five trials, 587 women: average RR 0.22, 95% CI 0.12 to 0.42). These data should be interpreted with caution because of the possibility of small-study effects or publication bias. In the largest trial, the reduction in pre-eclampsia was modest (8%) and the CI included the possibility of no effect.The composite outcome maternal death or serious morbidity was reduced with calcium supplementation (four trials, 9732 women; RR 0.80, 95% CI 0.66 to 0.98). Maternal deaths were no different (one trial of 8312 women: one death in the calcium group versus six in the placebo group). There was an anomalous increase in the risk of HELLP syndrome in the calcium group (two trials, 12,901 women: RR 2.67, 95% CI 1.05 to 6.82, high-quality evidence), however, the absolute number of events was low (16 versus six).The average risk of preterm birth was reduced in the calcium supplementation group (11 trials, 15,275 women: RR 0.76, 95% CI 0.60 to 0.97; I² = 60%; low-quality evidence); this reduction was greatest amongst women at higher risk of developing pre-eclampsia (four trials, 568 women: average RR 0.45, 95% CI 0.24 to 0.83; I² = 60%). Again, these data should be interpreted with caution because of the possibility of small-study effects or publication bias. There was no clear effect on admission to neonatal intensive care. There was also no clear effect on the risk of stillbirth or infant death before discharge from hospital (11 trials, 15,665 babies: RR 0.90, 95% CI 0.74 to 1.09).One study showed a reduction in childhood systolic BP greater than 95th percentile among children exposed to calcium supplementation in utero (514 children: RR 0.59, 95% CI 0.39 to 0.91). In a subset of these children, dental caries at 12 years old was also reduced (195 children, RR 0.73, 95% CI 0.62 to 0.87).Low-dose calcium supplementation (< 1 g/day) versus placebo or no treatmentTwelve trials (2334 women) evaluated low-dose (usually 500 mg daily) supplementation with calcium alone (four trials) or in association with vitamin D (five trials), linoleic acid (two trials), or antioxidants (one trial). Most studies recruited women at high risk for pre-eclampsia, and were at high risk of bias, thus the results should be interpreted with caution. Supplementation with low doses of calcium reduced the risk of pre-eclampsia (nine trials, 2234 women: RR 0.38, 95% CI 0.28 to 0.52). There was also a reduction in high BP (five trials, 665 women: RR 0.53, 95% CI 0.38 to 0.74), admission to neonatal intensive care unit (one trial, 422 women, RR 0.44, 95% CI 0.20 to 0.99), but not preterm birth (six trials, 1290 women, average RR 0.83, 95% CI 0.34 to 2.03), or stillbirth or death before discharge (five trials, 1025 babies, RR 0.48, 95% CI 0.14 to 1.67).High-dose (=/> 1 g) versus low-dose (< 1 g) calcium supplementationWe included one trial with 262 women, the results of which should be interpreted with caution due to unclear risk of bias. Risk of pre-eclampsia appeared to be reduced in the high-dose group (RR 0.42, 95% CI 0.18 to 0.96). No other differences were found (preterm birth: RR 0.31, 95% CI 0.09 to 1.08; eclampsia: RR 0.32, 95% CI 0.07 to 1.53; stillbirth: RR 0.48, 95% CI 0.13 to 1.83). AUTHORS' CONCLUSIONS High-dose calcium supplementation (≥ 1 g/day) may reduce the risk of pre-eclampsia and preterm birth, particularly for women with low calcium diets (low-quality evidence). The treatment effect may be overestimated due to small-study effects or publication bias. It reduces the occurrence of the composite outcome 'maternal death or serious morbidity', but not stillbirth or neonatal high care admission. There was an increased risk of HELLP syndrome with calcium supplementation, which was small in absolute numbers.The limited evidence on low-dose calcium supplementation suggests a reduction in pre-eclampsia, hypertension and admission to neonatal high care, but needs to be confirmed by larger, high-quality trials.
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Affiliation(s)
- G Justus Hofmeyr
- Walter Sisulu University, University of Fort Hare, University of the Witwatersrand, Eastern Cape Department of HealthEast LondonSouth Africa
| | - Theresa A Lawrie
- 1st Floor Education Centre, Royal United HospitalCochrane Gynaecological, Neuro‐oncology and Orphan Cancer GroupCombe ParkBathUKBA1 3NG
| | - Álvaro N Atallah
- Centro de Estudos de Saúde Baseada em Evidências e Avaliação Tecnológica em SaúdeCochrane BrazilR. Borges Lagoa, 564 cj 63Vila ClementinoSão PauloSão PauloBrazil04038‐000
| | - Maria Regina Torloni
- Centro de Estudos de Saúde Baseada em Evidências e Avaliação Tecnológica em SaúdeCochrane BrazilR. Borges Lagoa, 564 cj 63Vila ClementinoSão PauloSão PauloBrazil04038‐000
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Ward KA, Jarjou L, Prentice A. Long-term effects of maternal calcium supplementation on childhood growth differ between males and females in a population accustomed to a low calcium intake. Bone 2017; 103:31-38. [PMID: 28583879 PMCID: PMC5571891 DOI: 10.1016/j.bone.2017.06.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 04/25/2017] [Indexed: 12/11/2022]
Abstract
The importance of adequate calcium intakes for healthy growth and bone development has long been recognised. Recent evidence suggests that calcium supplementation may have sex-specific effects on bone growth in childhood. The aim was to describe the long-term effects of calcium supplementation in pregnant Gambian women with a low calcium intake (ISCRTN96502494) on offspring height, weight, bone and body composition in childhood, and whether the effects differ by sex. Children of mothers who participated in the original calcium supplementation trial were measured at age 8-12years using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography. Linear models tested for sex*supplement interactions before and after adjusting for current age and size in early life. 447 children, aged 9.2(SD 0.9) years, were measured. Significant sex*supplement interactions (p<0.05) were observed for many of the anthropometric and bone outcomes, Females whose mothers received calcium (F-Ca) were shorter, lighter with smaller bones and less bone mineral than those whose mothers received placebo (F-P), differences (SE) ranged from height=-1.0 (0.5)% to hip BMC -5.5 (2.3)%. Males from mothers in the calcium group (M-Ca) had greater mid-upper arm circumference (MUAC) (+2.0 (1.0)%, p=0.05) and fat mass (+11.6 (5.1)%, p=0.02) and tended towards greater BMC and size than those whose mothers were in the placebo group (M-P). The differences in anthropometry and body composition were robust to adjustment for current height and weight, whereas all bone differences became non-significant. F-P were taller with more BMC than M-P, whereas F-Ca had similar sized bones and mineral content to M-Ca. Calcium supplementation of pregnant women with low calcium intakes altered the childhood trajectories of growth and bone and body composition development of their offspring in a sex-specific manner, resulting in slower growth among females compared to placebo and accelerated growth among males by age 8-12years.
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Affiliation(s)
- Kate Anna Ward
- Nutrition and Bone Health, Medical Research Council Elsie Widdowson Laboratory, Cambridge, UK; MRC Lifecourse Epidemiology, University of Southampton, Southampton, UK.
| | - Landing Jarjou
- Calcium, Vitamin D and Bone Health, MRC Keneba, MRC Unit The Gambia, Gambia
| | - Ann Prentice
- Nutrition and Bone Health, Medical Research Council Elsie Widdowson Laboratory, Cambridge, UK; Calcium, Vitamin D and Bone Health, MRC Keneba, MRC Unit The Gambia, Gambia
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de Souza RJ, Eisen RB, Perera S, Bantoto B, Bawor M, Dennis BB, Samaan Z, Thabane L. Best (but oft-forgotten) practices: sensitivity analyses in randomized controlled trials. Am J Clin Nutr 2016; 103:5-17. [PMID: 26675766 DOI: 10.3945/ajcn.115.121848] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 11/04/2015] [Indexed: 01/15/2023] Open
Abstract
A randomized controlled clinical trial is the best way to minimize bias in ascertaining treatment effects, but the credibility of the results of a trial depends on the validity of the methods used to analyze the data, and the conditions under which such methods produce valid answers. A sensitivity analysis is a method to determine the robustness of trial findings by examining the extent to which results are affected by changes in methods, models, values of unmeasured variables, or assumptions. The goal of a sensitivity analysis is to identify results that are most dependent on questionable or unsupported assumptions. In this article, we briefly review the current use of sensitivity analyses in a random sample of published nutrition literature and provide a guide on the use of sensitivity analyses in randomized trials as to when to consider them, what to consider when planning them, and different methods of implementing them. We propose an 8-step strategy for improving the approach to conducting and reporting sensitivity analyses in nutrition-based trials.
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Affiliation(s)
- Russell J de Souza
- Department of Clinical Epidemiology & Biostatistics, Faculty of Health Sciences, Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Canada; Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Canada
| | - Rebecca B Eisen
- Department of Clinical Epidemiology & Biostatistics, Faculty of Health Sciences
| | - Stefan Perera
- Department of Clinical Epidemiology & Biostatistics, Faculty of Health Sciences
| | - Bianca Bantoto
- Department of Clinical Epidemiology & Biostatistics, Faculty of Health Sciences
| | - Monica Bawor
- Department of Clinical Epidemiology & Biostatistics, Faculty of Health Sciences
| | - Brittany B Dennis
- Department of Clinical Epidemiology & Biostatistics, Faculty of Health Sciences
| | - Zainab Samaan
- Department of Clinical Epidemiology & Biostatistics, Faculty of Health Sciences, Department of Psychiatry and Behavioral Neurosciences, St. Joseph's Healthcare Hamilton and Hamilton Health Sciences Mood Disorders Program, Hamilton, Canada
| | - Lehana Thabane
- Department of Clinical Epidemiology & Biostatistics, Faculty of Health Sciences, Center for Evaluation of Medicine, Population Health Research Institute, Hamilton Health Sciences, and System-Linked Research Unit, McMaster University, Hamilton, Canada; and
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Diogenes MEL, Bezerra FF, Rezende EP, Donangelo CM. Calcium Plus Vitamin D Supplementation During the Third Trimester of Pregnancy in Adolescents Accustomed to Low Calcium Diets Does Not Affect Infant Bone Mass at Early Lactation in a Randomized Controlled Trial. J Nutr 2015; 145:1515-23. [PMID: 26019245 DOI: 10.3945/jn.114.208140] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 05/04/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Pregnancy and lactation in adolescents with low calcium intake may impair fetal growth and infant bone mass. OBJECTIVE We investigated the effects of calcium plus vitamin D supplementation during pregnancy in Brazilian adolescent mothers consuming low calcium diets (∼600 mg/d) on fetal biometry and infant bone mass, and the relation between infant and maternal bone mass during early lactation. METHODS Infants of mothers who received calcium (600 mg/d) plus cholecalciferol (200 IU/d) supplementation (n = 30) or placebo (n = 26) from 26 wk of gestation until parturition were studied. Fetal biometric measurements at 23 and 36 wk of gestation were obtained from medical records. Infant anthropometric and total body bone measurements [bone mineral content (BMC), bone area (BA), and bone mineral density (BMD)] at 5 wk postpartum were assessed by dual-energy X-ray absorptiometry. Maternal BMD z scores for total body, lumbar spine, total hip, and femoral neck at 5 wk postpartum were obtained. Group comparisons were adjusted for significant covariates. RESULTS Maternal mean serum 25-hydroxyvitamin D was 59 nmol/L at baseline in both groups. No differences in fetal measurements at 36 wk of gestation were observed between the groups, except for body weight and its increment from 23 to 36 wk, which were higher in the supplemented group (6.8%, P = 0.014 and 10.5%, P = 0.07, respectively). Infant BMC (61.1 ± 21.7 g), BA (167 ± 79 cm(2)), and BMD (0.385 ± 0.069 g/cm(2)) did not significantly differ between the groups. In the placebo group, infant BMC and BA were negatively correlated with maternal BMD z scores for total body (r = -0.40 and r = -0.47; P < 0.05) and hip (r = -0.41 and r = -0.46; P < 0.05). In contrast, no correlations were observed in the supplemented group. CONCLUSIONS Calcium and vitamin D supplementation of the adolescents studied resulted in higher fetal body weight at 36 wk of gestation and had no effect on infant bone mass at 5 wk postpartum. Because correlations between maternal and infant bone mass were evident only in the placebo group, infant bone mass appeared to be more dependent on maternal skeletal mass when calcium intake was low. This trial was registered at clinicaltrials.gov as NCT01732328.
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Affiliation(s)
- Maria Eduarda L Diogenes
- Food and Nutritional Biochemistry Laboratory, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Brazilian National Cancer Institute José Alencar Gomes da Silva, Rio de Janeiro, Brazil
| | - Flávia F Bezerra
- Nutrition Institute, Rio de Janeiro State University, Rio de Janeiro, Brazil; and
| | - Elaine P Rezende
- Nutrition Institute, Rio de Janeiro State University, Rio de Janeiro, Brazil; and
| | - Carmen M Donangelo
- Food and Nutritional Biochemistry Laboratory, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; School of Nutrition, University of the Republic, Montevideo, Uruguay
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Buppasiri P, Lumbiganon P, Thinkhamrop J, Ngamjarus C, Laopaiboon M, Medley N. Calcium supplementation (other than for preventing or treating hypertension) for improving pregnancy and infant outcomes. Cochrane Database Syst Rev 2015; 2015:CD007079. [PMID: 25922862 PMCID: PMC10614032 DOI: 10.1002/14651858.cd007079.pub3] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Maternal nutrition during pregnancy is known to have an effect on fetal growth and development. It is recommended that women increase their calcium intake during pregnancy and lactation, although the recommended dosage varies among professionals. Currently, there is no consensus on the role of routine calcium supplementation for pregnant women other than for preventing or treating hypertension. OBJECTIVES To determine the effect of calcium supplementation on maternal, fetal and neonatal outcomes (other than for preventing or treating hypertension) as well as any possible side effects. SEARCH METHODS We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30th September 2014). SELECTION CRITERIA We considered all published, unpublished and ongoing randomised controlled trials (RCTs) comparing maternal, fetal and neonatal outcomes in pregnant women who received calcium supplementation versus placebo or no treatment. Cluster-RCTs were eligible for inclusion but none were identified. Quasi-RCTs and cross-over studies were not eligible for inclusion. DATA COLLECTION AND ANALYSIS Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. MAIN RESULTS Twenty-five studies met the inclusion criteria, but only 23 studies contributed data to the review. These 23 trials recruited 18,587 women, with 17,842 women included in final analyses. There were no statistically significant differences between women who received calcium supplementation and those who did not in terms of reducing preterm births less than 37 weeks' gestation (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.70 to 1.05; 13 studies, 16,139 women; random-effects model) or less than 34 weeks' gestation (RR 1.04, 95% CI 0.80 to 1.36; four trials, 5669). Most studies were of low risk of bias. We conducted sensitivity analysis for the outcome of preterm birth less than 37 weeks by removing two trials with unclear risk of bias for allocation concealment; the results then favoured treatment with calcium supplementation (RR 0.80, 95% CI 0.65 to 0.99; 11 trials, 15,379 women). There was no significant difference in infant low birthweight between the two treatment groups (RR 0.93, 95% CI 0.81 to 1.07; six trials, 14,162 infants; random-effects model). However, when compared to the control group, women in the calcium supplementation group gave birth to slightly heavier birthweight infants (mean difference 56.40, 95% CI 13.55 to 99.25; 21 trials, 9202 women; random-effects model).Three outcomes were chosen for assessment with the GRADE software: preterm birth less than 37 weeks; preterm birth less than 34 weeks; and low birthweight less than 2500 g. Evidence for these outcomes was assessed as of moderate quality. AUTHORS' CONCLUSIONS This review indicates that there are no clear additional benefits to calcium supplementation in prevention of preterm birth or low infant birthweight. While there was a statistically significant difference of 56 g identified in mean infant birthweight, there was significant heterogeneity identified, and the clinical significance of this difference is uncertain.
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Affiliation(s)
- Pranom Buppasiri
- Khon Kaen UniversityDepartment of Obstetrics and Gynaecology, Faculty of MedicineFaculty of MedicineKhon KaenKhon KaenThailand40002
| | - Pisake Lumbiganon
- Khon Kaen UniversityDepartment of Obstetrics and Gynaecology, Faculty of MedicineFaculty of MedicineKhon KaenKhon KaenThailand40002
| | - Jadsada Thinkhamrop
- Khon Kaen UniversityDepartment of Obstetrics and Gynaecology, Faculty of MedicineFaculty of MedicineKhon KaenKhon KaenThailand40002
| | - Chetta Ngamjarus
- Khon Kaen UniversityDepartment of Biostatistics and Demography, Faculty of Public Health123 Miltraparp RoadKhon KaenThailand40002
| | - Malinee Laopaiboon
- Khon Kaen UniversityDepartment of Biostatistics and Demography, Faculty of Public Health123 Miltraparp RoadKhon KaenThailand40002
| | - Nancy Medley
- The University of LiverpoolCochrane Pregnancy and Childbirth Group, Department of Women's and Children's HealthFirst Floor, Liverpool Women's NHS Foundation TrustCrown StreetLiverpoolUKL8 7SS
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Lamy O, Burckhardt P. Calcium revisited: part II calcium supplements and their effects. BONEKEY REPORTS 2014; 3:579. [PMID: 25328675 PMCID: PMC4189255 DOI: 10.1038/bonekey.2014.74] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 08/22/2014] [Indexed: 12/14/2022]
Abstract
Calcium supplements were tested in pregnancy and lactation, in childhood and adolescence, in pre- and postmenopausal women and in elderly persons with various effects on bone density and fracture incidence. They must be properly chosen and adequately used. In this case, the reported minor negative side-effects do not restrict their use. All these aspects are reviewed here.
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Hofmeyr GJ, Lawrie TA, Atallah AN, Duley L, Torloni MR. Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems. Cochrane Database Syst Rev 2014:CD001059. [PMID: 24960615 DOI: 10.1002/14651858.cd001059.pub4] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Pre-eclampsia and eclampsia are common causes of serious morbidity and death. Calcium supplementation may reduce the risk of pre-eclampsia, and may help to prevent preterm birth. OBJECTIVES To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child outcomes. SEARCH METHODS We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (28 March 2013) and contacted study authors for more data where possible. We updated the search in May 2014 and added the results to the 'Awaiting Classification' section of the review. SELECTION CRITERIA Randomised controlled trials (RCTs) comparing high-dose (at least 1 g daily of calcium) or low-dose calcium supplementation during pregnancy with placebo or no calcium. DATA COLLECTION AND ANALYSIS We assessed eligibility and trial quality, extracted and double-entered data. MAIN RESULTS High-dose calcium supplementation (≥1 g/day)We included 14 studies in the review, however one study contributed no data. We included 13 high-quality studies in our meta-analyses (15,730 women). The average risk of high blood pressure (BP) was reduced with calcium supplementation compared with placebo (12 trials, 15,470 women: risk ratio (RR) 0.65, 95% confidence interval (CI) 0.53 to 0.81; I² = 74%). There was also a significant reduction in the risk of pre-eclampsia associated with calcium supplementation (13 trials, 15,730 women: RR 0.45, 95% CI 0.31 to 0.65; I² = 70%). The effect was greatest for women with low calcium diets (eight trials, 10,678 women: average RR 0.36, 95% CI 0.20 to 0.65; I² = 76%) and women at high risk of pre-eclampsia (five trials, 587 women: average RR 0.22, 95% CI 0.12 to 0.42; I² = 0%). These data should be interpreted with caution because of the possibility of small-study effect or publication bias.The composite outcome maternal death or serious morbidity was reduced (four trials, 9732 women; RR 0.80, 95% CI 0.65 to 0.97; I² = 0%). Maternal deaths were not significantly different (one trial of 8312 women: calcium group one death versus placebo group six deaths). There was an anomalous increase in the risk of HELLP (haemolysis, elevated liver enzymes and low platelets) syndrome (two trials, 12,901 women: RR 2.67, 95% CI 1.05 to 6.82; I² = 0%) in the calcium group, however, the absolute number of events was low (16 versus six).The average risk of preterm birth was reduced in the calcium group (11 trials, 15,275 women: RR 0.76, 95% CI 0.60 to 0.97; I² = 60%) and amongst women at high risk of developing pre-eclampsia (four trials, 568 women: average RR 0.45, 95% CI 0.24 to 0.83; I² = 60%), but no significant reduction in neonatal high care admission. There was no overall effect on the risk of stillbirth or infant death before discharge from hospital (11 trials 15,665 babies: RR 0.90, 95% CI 0.74 to 1.09; I² = 0%).One study showed a reduction in childhood systolic BP greater than 95th percentile among children exposed to calcium supplementation in utero (514 children: RR 0.59, 95% CI 0.39 to 0.91). In a subset of these children, dental caries at 12 years old was also reduced (195 children, RR 0.73, 95% CI 0.62 to 0.87). Low-dose calcium supplementation (< 1 g/day)We included 10 trials (2234 women) that evaluated low-dose supplementation with calcium alone (4) or in association with vitamin D (3), linoleic acid (2), or antioxidants (1). Most studies recruited women at high risk for pre-eclampsia, and were at high risk of bias, thus the results should be interpreted with caution. Supplementation with low doses of calcium significantly reduced the risk of pre-eclampsia (RR 0.38, 95% CI 0.28 to 0.52; I² = 0%). There was also a reduction in hypertension, low birthweight and neonatal intensive care unit admission. AUTHORS' CONCLUSIONS Calcium supplementation (≥ 1 g/day) is associated with a significant reduction in the risk of pre-eclampsia, particularly for women with low calcium diets. The treatment effect may be overestimated due to small-study effects or publication bias. It also reduces preterm birth and the occurrence of the composite outcome 'maternal death or serious morbidity'. We considered these benefits to outweigh the increased risk of HELLP syndrome, which was small in absolute numbers. The World Health Organization recommends calcium 1.5 g to 2 g daily for pregnant women with low dietary calcium intake.The limited evidence on low-dose calcium supplementation suggests a reduction in pre-eclampsia, but needs to be confirmed by larger, high-quality trials. Pending such results, in settings of low dietary calcium where high-dose supplementation is not feasible, the option of lower-dose supplements (500 to 600 mg/day) might be considered in preference to no supplementation.
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Affiliation(s)
- G Justus Hofmeyr
- Department of Obstetrics and Gynaecology, East London Hospital Complex, University of the Witwatersrand, University of Fort Hare, Eastern Cape Department of Health, Frere and Cecilia Makiwane Hospitals, Private Bag X 9047, East London, Eastern Cape, South Africa, 5200
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Gabbay A, Tzur T, Weintraub AY, Shoham-Vardi I, Sergienko R, Sheiner E. Calcium level during the first trimester of pregnancy as a predictor of preeclampsia. Hypertens Pregnancy 2014; 33:311-21. [DOI: 10.3109/10641955.2013.877925] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Jarjou LMA, Sawo Y, Goldberg GR, Laskey MA, Cole TJ, Prentice A. Unexpected long-term effects of calcium supplementation in pregnancy on maternal bone outcomes in women with a low calcium intake: a follow-up study. Am J Clin Nutr 2013; 98:723-30. [PMID: 23902782 PMCID: PMC3743734 DOI: 10.3945/ajcn.113.061630] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Calcium supplementation of pregnant Gambian women with a low calcium intake results in lower maternal bone mineral content in the subsequent lactation. OBJECTIVE The objective was to investigate whether the lower bone mineral content persists long term. DESIGN All women in the calcium supplementation trial (International Trial Registry ISRCTN96502494) who had been scanned with dual-energy X-ray absorptiometry at 52 wk of lactation (L52; n = 79) were invited for follow-up when neither pregnant nor lactating for ≥3 mo (NPNL) or at 52 wk postpartum in a future lactation (F52). Bone scans and anthropometric and dietary assessments were conducted. RESULTS Sixty-eight women participated (35 at both NPNL and F52 and 33 at only one time point): n = 59 NPNL (n = 31 calcium, n = 28 placebo) and n = 44 F52 (n = 24 calcium, n = 20 placebo). The mean (±SD) time from L52 was 4.9 ± 1.9 y for NPNL and 5.0 ± 1.3 y for F52. Size-adjusted bone mineral content (SA-BMC) was greater at NPNL than at L52 in the placebo group (P ≤ 0.001) but not in the calcium group (P for time-by-group interaction: lumbar spine, 0.002; total hip, 0.03; whole body, 0.03). No significant changes in SA-BMC from L52 to F52 were observed in either group. Consequently, the lower SA-BMC in the calcium group at L52 persisted at NPNL and F52 (P ≤ 0.001): NPNL (lumbar spine, -7.5 ± 0.7%; total hip, -10.5 ± 1.0%; whole body, -3.6 ± 0.5%) and F52 (lumbar spine, -6.2 ± 0.9%; total hip, -10.3 ± 1.4%; whole body, -3.2 ± 0.6%). CONCLUSION In rural Gambian women with a low-calcium diet, a calcium supplement of 1500 mg/d during pregnancy resulted in lower maternal bone mineral content in the subsequent lactation that persisted long term. This trial was registered at www/controlled-trials.com/mrct/ as ISRCTN96502494.
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Prentice A. Standing on the shoulders of giants: Understanding calcium and vitamin D requirements. NUTR BULL 2013. [DOI: 10.1111/nbu.12043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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